Use of Pulp and Paper Sludge to Improve Performance of
Topsoil Layer in a Landfill Capping System

Petra Wildauer
Dipl. Ing. Chemistry, RWTH Aachen, Abt. Julich (Germany), 1987

Thesis Submitted in Partial Fulfillment of
the Requirements for the Degree of
Master of Science
in
Mathematical, Computer, and Physical Sciences
(Chemistry)

The University o f Northern British Columbia
July 2006
© Petra Wildauer, 2006

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APPROVAL

Name:

Petra Wildauer

Degree:

Master of Science

Thesis Title:

Use of Pulp And Paper Sludge To Improve Perfonuance Of
Topsoil Layer I n A X a n d f i l L r i n n i n n r
-------

Examining Committee:
Chair:
Le^usf"Associate Professor
Natural Resources and Environmental Studies Program
University of Northern British Columbia

Supervisor: Dr. Ron Thnng, rroressoi
Mathematical, Computer, and Physical Sciences Program
University of Northern British Columbia

Committee Member: Dr. Margot Mandy, A s^ciate Professor
Mathematical, Computer, and Physical Sciences Program
University of Northern British Columbia

Committee Memh^f: Dr. Joselito Arocena, Professor
Natural Resources and Environmental Studies Program
Canada Research Chair. Soil and Environmental Sciences
University'fffNorthern jTpfc&i Columbia

C^Co^rhfttee Member: Larry Gardner, AScT
Environmental Protection Section Head
ThompsonJRegion, Ministry of Water, Land and Air Protection

CommitteeTVfemfrgf: James Spankie, P.Eng.
Mill Environmental Supervisor - Northwood Pulp Mill
Canadian Forest Products Ltd.

External Examiner: Dr. Michael Rutherford, Associate Professor
Natural Resources and Environmental Studies Program
University of Northern British Columbia

Date Approved:

ULL i*), aooi

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ABSTRACT

Sludge is one of the major solid waste products in the pulping process. It
consists of wood fibers, fines, some inorganic fillers, and water. Prince George
mills produce approximately 11,000 wet tons of sludge annually. Presently, the
sludge is either landfilled or incinerated causing potential environmental
problems. Pulp mill sludge may be used as soil amendment in the topsoil layer of
a landfill cap to enhance plant growth and minimize the formation of cracks,
hence reduce erosion and infiltration problems.
The objective of this

research was to chemically and

physically

characterize sludge from two different pulping processes and to investigate their
suitability as soil amendment in the topsoil layer of a landfill cap.
Chemical

analysis

of

both

sludge

samples

revealed

that

metal

concentrations were below maximum allowable concentrations for municipal
sewage biosolids. Both sludges have a high C:N ratio and a neutral to alkaline
pH. The N immobilization and pH adjustment could be addressed with
appropriate fertilization. The type of sludge under consideration will determine
the fertilizer composition to enhance plant growth.
The high organic content and fibrous structure of the sludges decreased
the bulk density of the soil and increased its water holding capacity. Water
holding capacity (WHC) was determined by gravity and moisture retention curves
were established for sludge and soil samples, various sludge-soil mixtures and
sludge-soil layer systems. BCTMP sludge samples had a higher WHC than the
soil, resulting in higher water retention and higher amount of plant available water.

ii

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Kraft mill sludge samples showed the opposite effect on WHC, water retention
and plant available water. Soil amended with increasing amounts of sludge
resulted in increasing water retention. Layering systems showed that the soil
layers exhibited attributes of constant WHC, while the sludge layers varied
depending on their position within the layer system.
These attributes of the sludge used in this research would improve the
performance of the topsoil layer with less environmental impact than current
disposal options. The results and conclusions are not necessarily applicable to
any sludge in the pulp and paper industry.

iii

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Table of Contents
Abstract

ii

Table of Contents

iv

List of Tables

vi

List of Figures

x

Acknowledgements

xii

Chapter 1

Introduction

1

1.1

Landfill capping

1

1.2

Pulp and paper sludge

6

1.3

Environmental consideration

12

1.4

Project objectives

18

Chapter 2

Literature review

20

2.1

Sludge disposal alternatives

20

2.2

Case studies of various applications

24

2.3

Landfill applications

27

Chapter 3
3.1

Methods for chemical and physical characterization

31

Materials and methods

32

3.1.1

Sample collection

32

3.1.2

Sample storage

33

3.2

Sludge characterization

33

3.2.1

pH Determination

33

3.2.2

Moisture content

33

3.2.3

Bulk density

34

3.2.4

Porosity

35

3.2.5

Scanning electron microscopy and energy dispersive X-ray

35

3.2.6

Total carbon and total nitrogen

36

3.2.7

Ash content

36

3.2.8

Determination of macro- and micronutrients

37

3.2.9

Electrical conductivity and salinity

38

3.2.10

Effective cation exchange capacity (CECe)

39

3.2.11

Water holding capacity

39

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3.2.11.1
3.2.11.2
3.2.12

Chapter 4

Gravity or European method

39

Pressure plate experiment

41

Statistical analysis

44

Results and discussion

45

4.1

Baseline characterization

45

4.2

Chemical characterization

48

4.2.1

General properties

48

4.2.2

Macro- and micronutrients

50

Physical characterization

4.3

53

4.3.1

Bulk density and porosity

53

4.3.2

Water holding capacity by gravity

53

4.3.3

Pressure plate experiment

58

Chapter 5

Summary

73

Chapter 6

Recommendations for future work

76
78

References

Appendix A

Glossary

86

Appendix B

Determination of moisture content in sludge samples

88

Appendix C

Determination of total C and total N

90

Appendix D

Determination of ash content

91

Appendix E

Energy dispersive x-ray analysis

92

Appendix F

Cation exchange capacity

94

Appendix G

Elemental analysis

95

Appendix H

Determination of gravimetric water holding capacity

96

Appendix I

Pressure plate experiment

112

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List of Tables
TABLE 1:
TABLE 2:
TABLE 3:
TABLE 4:
TABLE 5:
TABLE 6:
TABLE 7:

TABLE 8:
TABLE 9:
TABLE 10:
TABLE 11:
TABLE 12:
TABLE 13:
TABLE 14:
TABLE 15:
TABLE 16:
TABLE 17:
TABLE 18:
TABLE 19:
TABLE 20:
TABLE 21:
TABLE 22:
TABLE 23:
TABLE 24:
TABLE 25:
TABLE 26:

Typical materials that comprise a final landfill cover system
Quality standards for productive soils
Comparison of macronutrient and micronutrient concentrations in
and paper sludge and municipal sewage biosolids
Plant macro- and micronutrients and their functions
Residuals index properties and hydraulic conductivity of sludge used
as barrier layer from previous studies
Properties of BCTMP and Kraft mill sludge compared with previous
data
Summary of results of the elemental analysis in oven-dried (105°)
mill and BCTMP sludge samples determined by ICP-AES and
literature data
Bulk density and porosity of BCTMP and Kraft mill sludge
Bulk density and gravimetric water holding capacity obtained from
original and blended Kraft mill and BCTMP sludge and soil samples
Bulk density and gravimetric water holding capacity obtained from
various Kraft mill sludge-soil mixtures
Bulk density and gravimetric water holding capacity obtained from
various BCTMP sludge-soil mixtures
Bulk density and gravimetric water holding capacity of 1, 2, and 3
layer systems of Kraft mill sludge
Bulk density and gravimetric water holding capacity of 1, 2, and 3
layer systems of BCTMP sludge
Volumetric moisture retention curve data with random errors for
BCTMP sludge, Kraft mill sludge, and soil
Volumetric moisture retention curve data with random errors for
BCTMP sludge-soil mixtures
Volumetric moisture retention curve data with random errors for
Kraft mill sludge-soil mixtures
Volumetric moisture content in % and bulk density in g/cm3 of
BCTMP sludge-soil mixtures
Volumetric moisture content in % and bulk density in g/cm3 of
Kraft mill sludge-soil mixtures
Total volumetric moisture content of 1,2, and 3 BCTMP sludge-soil
layer systems at 0.5, 1.0, and 5.0 bar pressure
Total volumetric moisture content of 1,2, and 3 Kraft mill sludge-soil
layer systems at 0.5, 1.0, and 5.0 bar pressure
Kraft mill sludge dried at 55° C
Kraft mill sludge dried at 80° C
Kraft mill sludge dried at 105° C
BCTMP sludge dried at 55° C
BCTMP sludge dried at 55° C
BCTMP sludge dried at 55° C

3
13
17
18
24
48

52
53
54
55
55
56
57
59
64
65
66
67
69
69
88
88
88
89
89
89

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TABLE 27:
TABLE 28:
TABLE 29:
TABLE 30:
TABLE 31:
TABLE 32:
TABLE 33:
TABLE 34:
TABLE 35:
TABLE 36:
TABLE 37:
TABLE 38:
TABLE 39:
TABLE 40:
TABLE 41:
TABLE 42:
TABLE 43:
TABLE 44:
TABLE 45:
TABLE 46
TABLE 47:
TABLE 48:
TABLE 49:
TABLE 50:
TABLE 51:
TABLE 52:
TABLE 53:
TABLE 54:
TABLE 55:
TABLE 56:
TABLE 57:

Total carbon and nitrogen raw data
Ash content of sludge and soil samples
Elemental analysis of Kraft mill sludge
Elemental analysis of BCTMP sludge
Effective cation exchange capacity and exchangeable Al, Fe, K, Mg,
Mn, and Na for BCTMP and Kraft mill sludge and soil samples
Elemental analysis of oven-dried BCTMP and Kraft mill sludge
by ICP-AES
Raw data for sludge and soil samples
Raw data for Kraft mill sludge-soil mixtures
Raw data for BCTMP sludge-soil mixtures
Total sample mass dry and Db for sludge and soil samples
Total sample mass dry and Db for Kraft mill sludge-soil mixtures
Total sample mass dry and Db for BCTMP sludge-soil mixtures
Raw data for Kraft mill sludge-soil layer systems and Db; 1, 2, and
3 layer systems
Raw data for BCTMP sludge-soil layer systems and Db; 1, 2, and
3 layer systems
Db and statistics for Kraft mill sludge-soil layer systems; 1, 2, and
3 layer systems
Db and statistics for BCTMP sludge-soil layer systems; 1, 2, and
3 layer systems
WHCg of sludge and soil samples
WHCg of Kraft mill sludge-soil mixtures
WHCg of BCTMP sludge-soil mixtures
WHCg of Kraft mill sludge-soil layer systems; 1, 2, and 3 layer
systems
WHCg of BCTMP sludge-soil layer systems; 1, 2, and 3 layer
systems
Raw data for moisture retention curve of Kraft mill sludge
Raw data for moisture retention curve of BCTMP sludge
Raw data for moisture retention curve of soil
Determination of random errors of bulk density, gravimetric (WHCg)
and volumetric moisture content (WHCV) for Kraft mill sludge
Determination of random errors of bulk density, gravimetric (WHCg)
and volumetric moisture content (WHCV) for BCTMP sludge
Determination of random errors of bulk density, gravimetric (WHCg)
and volumetric moisture content (WHCV) for soil
Raw data for moisture retention curve of Kraft mill sludge
Raw data for moisture retentioncurve of blended Kraft mill sludge
Raw data for moisture retention curve of Kraft mill
sludge-soil mixture 40:10
Raw data for moisture retention curve of Kraft mill

90
91
92
93
94
95
96
96
97
98
99
100
102
103

104
104
105
106
107
108
110
112
113
113
114
114
114
115
115
116

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sludge-soil mixture 30:20
Raw data for moisture retention curve of Kraft mill
sludge-soil mixture 25:25
TABLE 59 Raw data for moisture retention curve of Kraft mill
sludge-soil mixture 20:30
TABLE 60 Raw data for moisture retention curve of Kraft mill
sludge-soil mixture 10:40
TABLE 61 Raw data for moisture retention curve of BCTMP sludge
TABLE 62 Raw data for moisture retention curve of blended BCTMP sludge
TABLE 63 Raw data for moisture retention curve of BCTMP
sludge-soil mixture 40:10
TABLE 64 Raw data for moisture retention curve of BCTMP
sludge-soil mixture 30:20
TABLE 65 Raw data for moisture retention curve of BCTMP
sludge-soil mixture 25:25
TABLE 66 Raw data for moisture retention curve of BCTMP
sludge-soil mixture 20:30
TABLE 67 Raw data for moisture retention curve of BCTMP
sludge-soil mixture 10:40
TABLE 68 WHCg, Db, W HCV, and random errors of original Kraft mill sludge
TABLE 69 WHCg, Db, W HCV, and random errors of blended Kraft mill sludge
TABLE 70 WHCg, Db, W HCV, and random errors of Kraft mill sludge-soil
mixture 40:10
TABLE 71 WHCg, Db, WHCV, and random errors of Kraft mill sludge-soil
mixture 30:20
TABLE 72 WHCg, Db, WHCV, and random errors of Kraft mill sludge-soil
mixture 25:25
TABLE 73: WHCg, Db, WHCV, and random errors of Kraft mill sludge-soil
mixture 20:30
TABLE 74 WHCg, Db, W HCV, and random errors of Kraft mill sludge-soil
mixture 10:40
TABLE 75 WHCg, Db, W HCV, and random errors of original BCTMP sludge
TABLE 76 WHCg, Db, W HCV, and random errors of blended BCTMP sludge
TABLE 77 WHCg, Db, WHCV, and random errors of BCTMP sludge-soil
mixture 40:10
TABLE 78 WHCg, Db, W HCV, and random errors of BCTMP sludge-soil
mixture 30:20
TABLE 79: WHCg, Db, WHCV, and random errors of BCTMP sludge-soil
mixture 25:25
TABLE 80 WHCg, Db, WHCV, and random errors of BCTMP sludge-soil
mixture 20:30
TABLE 81 WHCg, Db, W HCV, and random errors of BCTMP sludge-soil
mixture 10:40

116

TABLE 58

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117
117
118
119
119
120
120
121
121
122
123
123
123
124
124
124
125
126
126
126
127
127
127
128

TABLE 82:
TABLE 83:
TABLE 84:

TABLE 85:

TABLE 86:
TABLE 87:

Raw data for bulk density, WHCg and WHCVdetermination of each
sludge and soil layer for Kraft mill sludge
Raw data for bulk density, WHCg and WHCVdetermination of each
sludge and soil layer for BCTMP sludge
Determination of bulk density, gravimetric and volumetric moisture
content with random errors and the total WHCVof the sludge-soil
layers for Kraft mill sludge
Determination of bulk density, gravimetric and volumetric moisture
content with random errors and the total WHCVof the sludge-soil
layers for Kraft mill sludge
Total volumetric moisture content of 1, 2, and 3 Kraft mill sludge-soil
layer systems at 0.5, 1.0, and 5.0 bar pressure with random errors
Total volumetric moisture content of 1, 2, and 3 BCTMP sludge-soil
layer systems at 0.5, 1.0, and 5.0 bar pressure with random errors

141

143

145

146
147
147

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List of Figures
FIGURE 1:
FIGURE 2:
FIGURE 3:
FIGURE 4:
FIGURE 5;
FIGURE 6:
FIGURE 7:
FIGURE 8:
FIGURE 9:

Simplified layout of sludge generation paths
Final sludge disposal practices
Outline for the sludge-soil layer systems
Pressure plate extractor set up
BCTMP sludge (1:1)
Kraft mill sludge (1:1)
SEM micrographs of BCTMP sludge (15x)
SEM micrographs of Kraft mill sludge (15x)
Moisture retention curves of BCTMP sludge, Kraft mill sludge and
soil from -0.1 to -15 bar with random errors
FIGURE 10: Moisture retention curves of BCTMP sludge, Kraft mill sludge and
soil from -0.1 to -2.5 bar with random errors
FIGURE 11: Moisture retention curves for BCTMP sludge-soil mixtures from
-0.1 t o -15 bar
FIGURE 12: Moisture retention curves for BCTMP sludge-soil mixtures from
-0.1 t o -2 .5 bar
FIGURE 13: Moisture retention curves for Kraft mill sludge-soil mixtures from
-0.1 t o -15 bar
FIGURE 14: Moisture retention curves for Kraft mill sludge-soil mixtures from
-0.1 t o -2 .5 bar
FIGURE 15: Moisture retention curves for Kraft mill sludge, Kraft mill sludge-soil
mixtures 40:10, 30:20, and 10:40 from -0.1 to -15 bar
FIGURE 16: Moisture retention curves for blended Kraft mill sludge, Kraft mill
sludge-soil mixtures 25:25 and 10:40 from -0.1 to -15 bar
FIGURE 17: Moisture retention curves for Kraft mill sludge, Kraft mill sludge-soil
mixtures 40:10, 30:20, and 10:40 from -0.1 to -2.5 bar
FIGURE 18: Moisture retention curves for blended Kraft mill sludge, Kraft mill
sludge-soil mixtures 25:25 and 10:40 from -0.1 to -2.5 bar
FIGURE 19: Moisture retention curves for Kraft mill sludge, Kraft mill sludge-soil
mixtures 40:10, 30:20, and 10:40 with random errors from
-0.1 t o -15 bar
FIGURE 20: Moisture retention curves for blended Kraft mill sludge, Kraft mill
sludge-soil mixtures 25:25 and 10:40 with random errors from
-0.1 t o -15 bar
FIGURE 21: Moisture retention curves for Kraft mill sludge, Kraft mill sludge-soil
mixtures 40:10, 30:20, and 10:40 with random errors from
-0.1 t o -2.5 bar
FIGURE 22: Moisture retention curves for blended Kraft mill sludge, Kraft mill
sludge-soil mixtures 25:25 and 10:40 with random errors from
-0.1 t o -2.5 bar
FIGURE 23: Moisture retention curves for BCTMP sludge, BCTMP sludge-soil
mixtures 40:10, 25:25, and 10:40 from -0.1 to -15 bar
FIGURE 24: Moisture retention curves for blended BCTMP sludge, BCTMP

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11
20
40
42
46
46
47
47
60
60
62
62
63
63
129
130
131
132

133

133

134

134
135

sludge-soil mixtures 20:30 and 30:20 from -0.1 to -15 bar
FIGURE 25: Moisture retention curves for BCTMP sludge, BCTMP sludge-soil
mixtures 40:10, 25:25, and 10:40 from -0.1 to -2.5 bar
FIGURE 26: Moisture retention curves for blended BCTMP sludge, BCTMP
sludge-soil mixtures 20:30 and 30:20 from -0.1 to -2.5 bar
FIGURE 27: Moisture retention curves for BCTMP sludge, BCTMP sludge-soil
mixtures 40:10, 25:25, and 10:40 with random errors from
-0.1 t o -15 bar
FIGURE 28: Moisture retention curves for blended BCTMP sludge, BCTMP
sludge-soil mixtures 30:20 and 20:30 with random errors from
-0.1 t o -15 bar
FIGURE 29: Moisture retention curves for BCTMP sludge, BCTMP sludge-soil
mixtures 40:10, 25:25, and 10:40 with random errors from
-0.1 to -2.5 bar
FIGURE 30: Moisture retention curves for blended BCTMP sludge, BCTMP
sludge-soil mixtures 30:20 and 20:30 with random errors from
-0.1 to -2.5 bar

136
137
138

139

139

140

140

xi

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Acknowledgements

The author would like to sincerely thank all the people who gave her their
encouragement and assistance to conduct this research. In particular, the author would
like to recognize:
Dr. R. W. Thring, my supervisor, for giving me this opportunity to realize this research
and support and guide me through this time.
The members of my committee: Dr. J. Arocena, Dr. M. Mandy, L. Gardner, and J.
Spankie for their input and guidance.
The environmental science, chemistry and central equipment laboratories for lending me
equipment and assisting me with sample analysis.
The Science Council of British Columbia and its GREAT scholarship for providing the
financial support required to complete this thesis.
Michele, Eric, Alida, Dave, Svetlana, and Geoffrey for their friendship and boosting me
up by telling me “that everything would work out”.
My husband for being so patient and encouraging while I completed my degree, for
rescuing my data and fixing all the little computer problems.
Finally, to my high school chemistry teacher, who not only inspired my interest in
chemistry but also helped me to set my career path.

I would like to dedicate this project to my friend, Sheri Merchant, whose excitement and
passion for the sludge project lifted me over some course work hurdles ( f July 2002).

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Chapter 1

Introduction

Municipal solid waste landfills are capped when they reach their disposal
capacities. The primary purposes of this cap are to minimize the infiltration of
precipitation and to limit the release of landfill gases. Landfill caps combine layers of
clay, sand, vegetated topsoil, and, sometimes, synthetic liners. To restore the local
environment, it is desirable that the top layer of the cap supports vegetation. Therefore,
additional material needs to be blended with the capping material to improve vegetation
growth.
The objective of this project was to chemically and physically characterize sludge
from two different pulping processes and investigate their suitability for use as landfill
capping material. Presently, the vast majority of sludge is either landfilled or incinerated.
Due to high waste-related disposal costs, increased difficulty and expense of permitting
new landfills, and the growing environmental concerns, the pulp and paper industry is
searching for technologies that are capable of reusing or recycling this sludge, one of the
most difficult wastes to handle or deal with.

1.1

Landfill capping
The safe and reliable disposal of municipal and industrial solid waste is an

important component of integrated waste management. Landfill is the term used to
describe the physical facilities used for the disposal of solid wastes in the surface soils of
the earth. Landfill refers to an engineered facility for disposal of municipal solid waste
(MSW) designed and operated to minimize public and environmental impacts. Since the
turn of the century, the use of landfills, in one form or another, has been the most
economical and environmentally acceptable method for disposal of solid wastes
throughout the world. Although many landfills have been constructed in the past with

1

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little or no thought for the long-term protection of public health and the environment, in
the last 20 years, practices have changed substantially (Kreith, 1994).
Municipal solid waste landfills are capped with a final cover when they reach
capacity. The landfill final cover system is designed to control fire, water infiltration, gas,
dust, blowing litter, and erosion, and to enhance site appearance. One main function of
the final cover system is to minimize infiltration of rainwater into the underlying waste
and therefore reduce the amount of leachate generated in the landfill. Most covers
incorporate a layered arrangement to minimize the quantity of water entering the landfill.
The configuration of the final cover system depends on the site, waste characteristics,
regulatory requirements, and future use of the site (GeoSyntec Consultants, 1995).
When water percolates through solid wastes that are undergoing decomposition,
both

biological

materials

and

chemical

constituents

are

leached

into

solution

(Tchobanoglous et al., 1993). As leachate percolates through the underlying strata,
many of the chemical and biological constituents originally contained in it will be
removed by the filtering and adsorptive action of the material composing the strata. In
general, the extent of this action depends on the characteristics of the soil, especially the
clay content. Because of the potential risk involved in allowing leachate to percolate to
the groundwater, best practice calls for its elimination or containment (Tchobanoglous et
al., 1993).
The purpose in the design of a final landfill cover system is to minimize the
infiltration of leachate into the subsurface soils below the landfill thus reducing the
potential for groundwater contamination. A number of cover system designs have been
developed to minimize the movement of leachate into the subsurface below the landfill.
In general, the final cover system is a combination of different layer types: surface layer,
protection layer, drainage layer, barrier layer, gas collection layer, and foundation layer.

2

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Each of the layers has one or more functions and the material typically used to construct
them are listed in table 1.
Table 1: Typical materials that comprise a final landfill cover system (GeoSyntec Consultants,
1995)

Component

Surface layer
Protection
layer
Drainage
layer
Barrier layer
Gas collection
layer
Foundation
layer

Typical materials

topsoil; cobbles,
paving material
soil; cobbles
sand, gravel; geonet,
geotextile
clay, geomembrane
sand, gravel,
geotextile, geonet
soil, selected waste

Purpose

support vegetation growth,
promote rainwater run-off
promote rainwater run-off,
prevent penetration by roots
limit buildup of hydraulic head
on top of barrier layer, reduce
infiltration
minimize leachate generation
collect and transmit generated
landfill gas
provide subgrade for overlying
layers of final cover

Thickness

min. 6”
min. 24”
40 - 60 mil

min. 18”
min. 12”
min. 12”

To meet the above mentioned purposes, the final landfill cover system must:
a) be able to withstand climatic extremes (e.g., hot/cold, wet/dry, and freeze/thaw
cycles),
b) be able to resist water and wind erosion,
c) have stability against slumping, cracking and slope failure, and downslope slippage
or creep,
d) resist the effects of differential landfill settlements caused by the release of landfill
gas and the compression of the waste and the foundation soil,
e) resist failure due to surcharge loads resulting from the stockpiling of cover material
and the travel of collection vehicles across completed portions of the landfill,
f)

resist deformation caused by earthquakes,

g) withstand alterations to cover materials caused by constituents in the landfill gas,
h) resist the disruptions caused by plants, burrowing animals, worms, and insects
(Kreith, 1994).

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A 1988 study by the U.S. Environmental Protection Agency (EPA) of randomly
selected landfills revealed that the vast majority of final landfill cover systems are
leaking, and many have caused severe contamination of the groundwater and
surrounding ecosystems

(Dwyer,

1998).

Examining the factors that affect cap

performance, it is apparent that hydrologic and erosional processes account for most of
the performance-related problems (Duguid, 1977; Jacobs et al., 1980; Hakonson et al.,
1982). For example, erosion associated with runoff can breach the cap and expose
waste to the biosphere (Nyhan and Lane, 1982; Nyhan et al., 1984). The drastic
outcomes motivated a new research area in waste management.
The instability of existing cover systems and increasing costs for recommended
cover materials required by regulatory authorities suggest a broad variety of research
projects on suitable alternative cover materials.
The British Columbia Landfill Criteria (MoELP, 1993) set minimum standards for
landfill covers, specifying permeability and construction materials. The cover must be
configured such that it can be maintained efficiently and be amenable to relatively easy
repair. Components of this conventional closure system may be modified if the proposed
alternative performs to an equivalent standard.
The final vegetative cover is the only mechanism that almost completely controls
infiltration independent of site location. The majority of precipitation is unable to infiltrate
the landfill because of surface slopes and runoff control. Slope and permeability are two
parameters that are largely variable and controllable by various engineering methods.
T h e s e p a ra m e te rs d e te rm in e th e qu an tity o f w a te r th a t a ffec t the landfill, a la rg e portion

of which is captured by a surface collection system and is diverted away from the landfill.
If a dense vegetative cover is present on the landfill, the evapotranspiration of these
plants can be considerable. Depending on the local climate and annual precipitation, up

4

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to 60% of the water may evaporate and, depending on the slope grades, another 5 to
20% can be diverted on the surface (Bilitewski et al., 1994).
The function of the surface layer is to cover and protect the barrier layer from
water and wind erosion, desiccation, freeze-thaw, and penetration by equipment or
burrowing animals, and to support the growth of vegetation. Soils capable of supporting
vegetation growth are used in the surface layer. Other materials may also be used in the
surface layer such as cobbles and paving materials, although these applications are rare
(GeoSyntec Consultants, 1995).
The surface layer of the final cover system will be exposed to environmental
conditions over the design life of the landfill. During this time period, erosion and
sediment control measurements are implemented to minimize soil loss due to rain,
runoff, and wind, prevent the development of rills or gullies, protect the underlying layers
of the cover system including the barrier layer, and minimize sediment impact to the
surrounding environment (GeoSyntec Consultants, 1995).
According to the universal soil loss equation (Hillel, 1998), soil loss is related to
rainfall intensity, soil type, length and inclination of slope, vegetation, and land
management practices. To reduce soil loss, certain criteria for construction material,
construction of the surface, plant selection, and maintenance of the surface layer have to
be implemented. Soils or other materials used in the surface layer are selected to be of
appropriate texture, organic content, salt content, acidity, and nutrient content for plant
growth depending on the plant species and climatic conditions at the site.
The failures of existing cover systems (from 163 landfills, 146 have groundwater
contamination, EPA 1988) and results of several research projects support the need for
finding an adequate capping system with regards to ecological and economical aspects
based on site specific parameters (e.g. climate, geology, hydrogeology, leachate and
landfill gas management, end use) (Dwyer, 1998; Siuru, 1996; Hakonson, 1997). EPA

5

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recommends a soil tolerance level of 4.4 tons ha'1 yr'1 to prevent deflation of the cover
surface over the lifetime of the site. Cover design features that are used to prevent
erosion include the establishment of vegetation, the use of mulching techniques,
synthetic mats, controlling slope and slope length, and the construction of terraces or
benches (Hakonson, 1997).
Depending on the capping system, costs range from $400,000 to $500,000 per
hectare (Dwyer, 1997). Hence, the landfill is operated on a 'user pay' basis; wherein
tipping fees are set to recover these future costs. Late implementation of these costs
would end in a drastic increase of the tipping fees.

1.2

Pulp and paper sludge
Pulp mill sludge, hereafter referred to as sludge, is a by-product of the pulp and

paper industry. The pulp and paper industry in the United States generates 5.3 million
metric tons of sludge annually (dry weight) (National Council for Air and Stream
Improvement (NCASI), 2000). Quebec and Ontario mills produce an estimated 720,000
metric tons per year (Chong et al., 1988), while a Kraft mill in Prince George produces
approximately 10,950 wet tons of sludge per year (Sigfusson, 1999). Presently, the
sludge is treated as an industrial waste and either landfilled or incinerated. Sludge
disposal poses significant environmental liabilities, logistical problems, and economic
burdens. Paper mills spend between $50 and $100 per ton to dispose of the sludge at a
typical landfill. Pressured by high waste-related disposal costs, increased difficulty and
expense of permitting new landfills, accompanied by growing environmental concerns,
the pulp and paper industry is searching for beneficial alternatives to dispose of sludge.

Paper making is a three step process. First, the source of cellulose fiber has to
be identified. The source can be wood, recovered paper or non-woody plants. In the

6

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second step, usable cellulose fibers are produced (pulping). In the final step, paper is
made after formatting sheets of pulp, pressing and drying. The main processes used in
the pulp and paper industry to make pulp are mechanical pulping, semi-mechanical
pulping, and chemical pulping.
Mechanical (groundwood or refiner) pulping uses physical forces to separate
wood fibers, resulting in a high yield pulp that is characterized by shorter fibers and
relatively low strength (Mabee, 2001). However, it is a lower cost method compared to
producing pulps for other useful applications than from chemical pulping. Also,
compared to chemical pulping which only produces about 50% yield of pulp from the
starting wood feedstock, mechanical pulping operations typically attain about 100%
yields. Groundwood pulps are made by forcing a log against the face of a cylindrical
abrasive stone which rotates at high speed. Refiner pulps are made by passing wood
chips in water through a set of disc refiners (one or both rotating at high speed) (Walker,
1993).
Semi-mechanical pulping techniques include the addition of heat and/or
chemicals. Thermomechanical pulps (TMP), chemi-thermomechanical pulps (CTMP),
and bleached chemi-thermomechanical pulps (BCTMP) can be produced after the initial
mechanical process. Mechanical and semi-mechanical pulps account for only 15% of
North America’s total pulp output (Mabee, 2001). The current trend in the industry has
been an increase in semi-mechanical and less investment in purely mechanical pulping.
Chemical pulping also includes CTMP and BCTMP, as well as alkaline pulping,
and sulphite pulping. Alkaline or acidic chemicals are used to dissolve lignin and release
individual fibers. This method of pulping can work in both high and low pH ranges, has
an increased chemical to wood ratio, uses more severe cooking, and the pulp is readily
bleached (Roberts, 1996). The CTMP process produces pulps with short average fiber
length, resulting in low paper strength (Mabee, 2001). A CTMP mill generally uses less

7

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power than the BCTMP process and has pulp yields of 85-90% (MacDonald et al.,
1969). Alkaline pulping, also known as Kraft or sulphate process, is the most common
method used in the pulp and paper industry, and is responsible for approximately 80% of
North American pulp production (Mabee, 2001). Kraft pulping produces pulp in good
yields and is consistent with the highest pulp quality and strength (Biermann, 1993).
Paper is generally made out of a blend of hardwood and softwood to meet the
strength and printing surface demands of the customer. Wood is mostly composed of
cellulose, hemicellulose, lignin, and extractives. Cellulose is a highly suitable raw
material with wide applications and shows small morphological differences among
species of trees (Schuerch, 1989). It consists of long, straight chains of glucose
monomers. It forms the skeleton of the plant cell wall and has the most desired
properties for making paper. These fibers are long, strong and translucent (Blum, 1996).
Hemicelluloses are short, branched polysaccharides from a variety of sugars.
This results in a polymer with a lower molecular weight than cellulose. Hemicelluloses fill
in space in the plant cell wall and make up 20% of the total wood mass, although this
fraction can change between soft and hardwood species. They are more soluble in water
and thus are often removed during the pulping process.
Lignin is the most complicated wood macro polymer. Unlike cellulose and
hemicellulose, lignin is not fibrous, and is composed mostly of aromatics (Glasser et al.,
1996). It is an amalgamation of two (or three) principal phenylpropane groups and their
derivatives, which combine in countless numbers of ways to produce a very large,
am o rp h o u s m o le cu le . Th is th re e dim en sio n al cross-linked p o lym er o f h e te ro g e n e o u s

structure generally acts as an interfiber bonding agent, imparting strength and
cohesiveness to the physical structure of the tree (Zakis, 1994). The presence of lignin is
considered undesirable by the pulp and paper industry, as it hampers the production of

8

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quality paper and imparts color to the nearly white tone of cellulosic matter. Lignin
usually makes up 20% of the total wood mass (Mabee, 2001).
Extractives is a collective term referring to extractable components and trace
elements found in wood. Some of these substances include fatty acids, resins, tannins,
sugars, resenes, turpenes (appendix A), gums, and waxes (Roberts, 1996). These
components serve no structural function, and normally form the smallest portion of the
total wood mass at approximately 3-8% (Mabee, 2001).
Pulp mill sludge represents the waste portion of the pulping process. It contains
knotted and separated wood fibers, dirt, and any other materials introduced through the
pulping or recycling process. The principle component of sludge is water, which makes
up more than half of the total mass of sludge even after dewatering (Mabee, 2001).
Sludge is mainly composed of unused cellulose and is produced in various stages of the
pulping process (Figure 1). As the wood input, the wood processing and the subsequent
effluent treatment varies greatly, so does the composition of the sludge. The physical
and chemical characteristics of the sludge of a single mill changes over time, and the
sludges from different mills using similar processes will exhibit different properties. A
better understanding of the characteristics of sludge is needed to come up with more
effective and economically viable means of disposal and/or recycling.
As governmental regulations require that at least 10% of manufactured paper
must be recycled, more and more paper mills are using recycled paper in the
manufacture of paper. Production of paper from recycled materials increases the amount
of sludge produced at paper mills (Coburn and Dolan, 1995). Because of recycling, more
unusable, short, odd-shaped fibers (cellulose) are generated from post-consumer fibers
than from virgin pulp.
Sludge or wastewater treatment plant solid residuals are those solid materials,
collected in the process of treating water used in the mill prior to release into the

9

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environment. Typically, these materials consist of solids collected in primary treatment
(separation of solids from raw wastewater) and secondary treatment (biological
treatment followed by clarification to separate biosolids) (NCASI, 2000). Primary sludge
is produced through the physical cleaning of the wastewater stream. It is collected in
screens and filters and is fairly clean, consisting of wood fibers, fines, some inorganic
fillers, and water (Mabee, 2001). Primary sludge is usually easy to dewater because of
the relatively high fiber to fines ratio of the organics and because of the high proportion
of woody-organic material in the sludge (Kennedy et al., 1989). The moisture content
varies from 30 to 70% depending on the drying process employed. As there is ten times
more primary then secondary residual they are combined to facilitate handling.
Primary sludge is derived from primary clarification treatment and is comprised
predominantly of wood fibers. Because of the high wood fiber content, primary sludge
has low nitrogen (N) concentration, ranging from 0.05 to 0.9%, with C:N ratios often
ranging from 100:1 to 300:1. Secondary sludge is derived from biological treatment of
effluent during which N and P are commonly added. This sludge consist largely of
microbial biomass and has higher concentrations of N and P and lower C:N ratios
ranging from 5:1 to 20:1. Both primary and secondary sludge can provide significant
sources of other macro- and

micronutrients,

although concentrations of these

constituents vary widely (NCASI, 2000). The vast majority of sludge is combined primary
and secondary sludge representing 54% of the total residual production (NCASI, 1999b).
A simplified layout of sludge generation paths is shown in Figure 1.

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Centrifugal Cleaners
(Varying Consistencies)

Mechanical Pulping/
Chemical Pulping/
Recycling

Screens
(Varying P ressu res/
C onsistencies)

Raw Materials

Flotation Deinking

Refiners/
Fiberizers/
Dispensers
Secondary Treatment:
ActivatedSludge/
Aerated Lagoon

Pulp
Headbox

Paper Machine
PRIMARY SLUDGE

SECONDARY SLUDGE

"1 {
j —©

▼
PRO D UC T

Sludge Press

Mixed Sludge

Figure 1: Sim plified layout o f s ludge g eneration paths after M a b e e , 2001
A to D : Recovered sludge sources

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The sludge is also generally low in potential environmental contaminants. In
recent years the reduction of metal concentrations in ink, analysis of raw materials and
processing chemicals led to lower metal concentrations in the sludge. Nevertheless,
chemical characterization is important as the metal concentrations in sludge wood fibers
are largely derived from the manufacturing process.

1.3

Environmental considerations
The high organic matter content of sludge represents a valuable resource as soil

amendment (Bellamy et al., 1995; Bowen et al., 1996; Edwards, 1997; Carpenter and
Fernandez, 2000) when soils are depleted or subject to erosion. Sludge is also rich in
macro- and micronutrients. The organic matter and nutrients are the two main elements
that make the use of this kind of waste on agricultural land as fertilizer and organic soil
amendment suitable.
Although attractive for use as soil amendment, there can be potentially harmful
effects

from

the

sludge

depending

on

its

constituents.

The

most

significant

environmental concerns associated with the land application of sludge are the potential
for constituent movement - either down and out of the soil profile potentially entering
surface or groundwater, or the assimilation into plants and associated food chain effects.
This is largely dependent on the volume of material applied, concentrations of trace
elements, mobility and toxicity of elements from the materials, and incorporation of the
elements into living organisms (Barker et al., 2000; Mullen, 2002). Sludge properties
such as percent organic matter, pH, cation exchange capacity, texture, and timelines for
microbial modification are expected to influence short and long term metal and nutrient
mobility. In terms of soil quality, the British Columbian Landscape Association (BCLA,
2001) has set quality criteria for boron (B), total nitrogen (N), phosphorus (P), potassium

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(K), calcium (Ca), and magnesium (Mg) besides C:N ratio, organic matter concentration
and pH. These standards are listed in Table 2.

Table 2: Quality standards for productive soils (BCLNA, 2001).

Constituent

Units

Range

C:N
Organic matter
Acidity
Boron
Total N
Phosphorus
Potassium
Calcium
Magnesium

ratio
%
PH
ppm
%
ppm
ppm
ppm
ppm

< 40
3-5
6-7
<1
0.2-0.6
20-100
50-250
1500-2000
175-250

Nitrogen (N) content often limits the effectiveness of sludge as a soil amendment
(Edwards, 1997; O’Brien, 2001). Only secondary sludge contains significant quantities of
N. Because of their low N concentrations and high C:N ratios, primary sludge can induce
N deficiencies in vegetation when land applied. As with most organic material, soil
microorganisms utilize both C and N during decomposition of sludge applied to soil.
Since the C:N ratio of the sludge is much higher than that of microbial cells (roughly 7:1),
soil microorganisms must utilize inorganic N (i.e., NH4+ and N 0 3") from the surrounding
soil matrix during sludge decomposition. The immobilized N is not lost from the system,
but is synthesized into organic forms that are unavailable for plant uptake until the
microbes die and decompose themselves. This process can reduce N leaching when
high N sludges are applied, but is also the cause of potential N deficiencies in vegetation
when low N sludges are used. Depending on the N concentration in the surrounding soil,
primary sludge may have to be applied in limited quantities or external sources of N
added to prevent such deficiencies in the soil sludge system.

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As secondary sludge contains mainly microbial biomass and nutrients (primarily
N and P) the properties of the combined sludges depend on the proportion of primary
and secondary sludge in the mix, and the type of products being produced by the mill.
Secondary sludge can thus provide a valuable source of N for vegetation, but there is
also more potential for N leaching and runoff if high application rates are used (NCASI,
200 0 ).

Organic matter, such as sludge, has a direct effect on water retention because of
its hydrophilic nature, and an indirect effect because of the modification of the soil
structure that may be affected due to the presence of the organic matter. Porous media
like soil consist of solid material and void or pore space. Air and water and possibly nonaqueous phase liquids occupy the pore space. The spatial arrangement of the soil
particles relate to both the size and shape of the components and their arrangement in
aggregates. There are two broad categories of aggregates. Microaggregates are less
than 250 pm in diameter and macroaggregates more than 250 pm. Pore diameters in
microaggregates mainly range from 0.2 to 6 pm; in macroaggregates from 25 to 100 pm.
Pore size determines the hierarchy at which pores remain water-filled at differing soil
water potentials (Paul et al. 1996).
The relation between the soil water content and the soil water suction (matric
potential) is a fundamental part of the characterization of the hydraulic properties of a
soil. The water retention function relates a capacity factor, the water content, to an
intensity factor, the energy state of the soil water. The term soil water is used for the
solution or liquid phase of the soil (Klute, 1986). A soil is composed of 25% water, 25%
air, 47% minerals and 3% organics (Klocke et al., 1996). The amount of water in the soil
influences many processes, including gas exchange with the atmosphere, diffusion of
nutrients to plant roots, soil temperature, and the speed with which solutes move through
the root zone during irrigation or rainfall. The force with which water is retained by the

14

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soil matrix also affects the amount of drainage occurring under gravity, and the extent of
upward movement of water and solutes against gravity (Gardner et al., 1991). The soil
water characteristic curve (also called moisture characteristic, matric potential, or water
retention curve) shows the relationship between water content and soil suction in the
vadose zone (Burckhard et al., 2000). The terms matric potential, matric suction, and soil
water suction are used interchangeably. Soil suction is defined as the negative gauge
pressure, relative to the external gas pressure on soil water. It describes the soil’s ability
to store and release water. If the soil water retention curve is known then it is possible to
estimate the amount of water available to plant roots. The upper soil moisture limit for
plant available water is considered to be at field capacity. The micropores are still filled
with water and can supply plants with needed water. The matric potential will vary from
soil to soil but is generally in the range of -10 to -30 kPa (Brady et al., 1999). The lower
soil moisture limit for plant available water is the permanent wilting point (PWP). There is
only some water remaining in the smallest of the micropores as a thin film. By
convention the permanent wilting point is the amount of water retained by the soil when
the water potential is -1500 kPa. Moisture retention curves of soil samples are
determined in the laboratory by using a pressure plate apparatus. This equipment allows
the application of successive suction values and repeated measurement of the
equilibrium soil wetness at each suction.
Sludge as an organic amendment affects soil structure by increasing soil
aggregation and stability. In well-aggregated soil, the interaggregate macropores drain
very quickly, while the intra-aggregate micropores tend to retain their moisture against
gravity. On the other hand, a dispersed or compacted soil has few macroaggregates and
drains very slowly. Air entry and oxygen diffusion are thereby affected. Depending on the
amount of organic matter present, soil organic matter can contribute to the retention of
soil moisture. The moisture retention or water holding capacity represents the temporary

15

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internal drainage or redistribution of water in the soil, responsible for maintaining an
amount of moisture for plants to survive during periods between rains or irrigations.
Organic matter increases soil aggregation and stability, reduces bulk density, and
increases water-holding capacity and retention (Khaleel et al., 1981; Metzger and Yaron,
1987; Tester, 1990; Hill and James, 1995). The increased soil aggregation is also due to
increased microbial activity, which increases soil porosity (Hill and James, 1995). Over
time microorganisms incorporate carbon into soil organic matter (Camberato et al.,
1997). As sludge decomposes, carbon is lost to the atmosphere as carbon dioxide,
which gradually decreases the C:N ratio and increases the availability of nitrogen for
plant growth.
The concentration of organic matter in soil is mainly responsible for water and ion
retention and supplying both to plants. High and low concentrations of organic matter
limit soil productivity.
Metal and nutrient availability in part depend on the soil acidity. Soil acidity is
affected by low pH as well as the effects the pH has on metal and micronutrient
availability. The U.S. EPA has established metal loading limits for land-applied municipal
sewage sludge, which generally have high metal concentrations compared to paper mill
sludge (Table 3). In British Columbia the metal contents in soils used for specific sites
such as agricultural, urban park, residential, commercial and industrial lands are
regulated under the Contaminated Sites Regulation.

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Table 3: Comparison of macro- and micronutrient concentrations in pulp and paper sludge a and
municipal sewage biosolids d (NA SCI, 2000).

NCASI 54 Mill Survey bc

range

Municipal sewage biosolidsd

median

range

median

Macronutrients (g/kg)
N
0.51 -87.5
P
0.01 -25.4
K
0 .1 2 -1 0
0 .2 8-210
Ca
Mg
0 .2 -1 9.0
S
0 .2 -2 0 .0

8.98
2.35
2.2
14
1.55
4.68

< 1.0-210
< 1.0-150
0.2 - 650
1 .0-250
0 .3 -2 5 .0
6 .0 -1 5

32.0
14.0
2.3
27.0
4.0
11.0

Micronutrients/Metals (mg/kg)
<0.1 - <11
Ag
Al
590 - 59000
As
<0.07-8.3
B
<1 -491
Ba
17.9-1800
Cd
<0.09 - 56
Cl
<0.06 - 8500
Co
0 -9 .7
Cr
3.0 - 2250
Cu
3 .9 -1590
97.1 - 10800
Fe
0.0009 - 3.52
Hg
Mn
13-2200
<2.5-14.0
Mo
300 - 66700
Na
Ni
1 .3 -1 33
Pb
<0.05 - 880
Se
<0.01 -<31
Sn
<70.6
Ti
3100-76000
Zn
13 -3780

0.55
13400
1.2
25.0
160.0
1.2
383
NA
42.0
52.0
1540
0.35
155.0
NA
2200
18.3
28
0.21
NA
NA
188.0

NA
1000- 13500
0 .3-315.6
4 -1 0 0 0
<0.01 - 9000
0.7 - 8220
NA
1 -260
2.0 - 3750
6 .8 -3120
1000- 15400
0 .2 -4 7 .0
32 - 9870
2.0 - 67.9
100-30700
2.0 - 976
9 .4 -1 67 0
0 .5 -7 0 .0
40 - 700
NA
38 - 68000

NA
4000.0
6
33
200
7
NA
10
40
463
1700
4
260
11
2400
29
106
5
150
NA
725

a Concentrations o f som e m etals in sludge have declined in recent years due to reductions
in m etal concentrations in inks and more careful scrutiny o f raw m aterials and
processing chem icals. For this reason, m etal concentrations in sam ples collected
prior to 1990, particularly m axim um values, m ay be higher than those in present
day sludges and should be interpret with a high degree of caution.

bAn assortm ent of primary, secondary & com bined sludge.

0 N C A SI 1984

N A = not available

d McG overn et al. 1983

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The total trace element content of a soil may not relate to the plant growth; as
only a portion of the total metal is available to the plant through absorption from the soil
solution (Pais and Jones, 1997). As different plant species have different elemental
needs, this would be another consideration in the suitability of using sludge. Table 4 lists
typical ranges of the plant macro- and micronutrients required for plant growth and their
primary function in plants.

Table 4: Plant macro- and micronutrients and their functions (W hitehead, 2000).

Constituent

Typical Range

Primary Function

Macronutrients
N
P

2.0-3.5%
0.2-0.5%

S
Ca
Mg
K

0.15-0.60%
0.6-0.8%
0.25-0.30%
1.0-3.5%

required for protein synthesis
transfer of energy through A D P to A TP for energy
storage
form amino acids which are incorporated into proteins
cell wall stabilization and osmotic regulation
photosynthesis and protein synthesis
open/close stomata and transport photosynthate

Micronutrients
B
Cu
Fe
Mn
Mo
Zn

8-15 ppm
10-15 ppm
150-175 ppm
70-100 ppm
0.1-4.0 ppm
35-40 ppm

cell wall synthesis and membrane function
photosynthesis and nitrogen fixation
Constituent of proteins involved in redox reactions
electron transfer and detoxification of free radicals
N metabolism (conversion of ammonium to nitrate)
enzyme catalyst

Since the late 1980s, dioxins have been an environmental concern with sludge
derived from chlorine-based bleaching processes. Over the last decade; however,
new technologies have reduced dioxin concentrations in bleaching mill effluents and
residuals (sludge) (NCASI, 2000). Although concentrations of metals and potential
organic contaminants in sludge are generally low, elevated concentrations can occur
in some situations and should be determined prior to establishing a recycling path.
1.4

Project objectives
The focus of this research was to evaluate the moisture retention properties of

18

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sludge amended soil in a laboratory set up in order to determine the usefulness of
sludge as landfill cover. The moisture retention influences the available amount of
water for plants. Organic matter increases water holding capacity. As the water
holding capacity affects the water uptake by plants, it is important for the final layer of
a landfill capping system. The final layer is also exposed to water related damage
resulting in soil loss and further infiltration. Sludge amendment could result in higher
absorption of water, thus reducing infiltration to the barrier layer.

19

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Chapter 2

Literature Review

Currently, 67% of sludge produced in North America is landfilled or incinerated,
neither of which utilizes the potentially valuable properties of this paper mill by-product
(Carpenter and Fernandez, 2000). Only 13% of the sludge is reused or recycled. The
pulp and paper industry has sought alternatives to sludge disposal since the early 80’s.
At the same time, individual pulp companies privately owned over 50% of landfills used
in the pulp and paper industry. This figure is declining, due to increasingly stringent
requirements for siting and construction (Glowacki, 1994).

2.1

Sludge disposal alternatives
Since sludge is mainly composed of organic fibers other disposal options are

incineration, land application, and recycling/reusing the fiber-rich material. The sludge
disposal practices are shown in Figure 2. Figure 2 summarizes a survey conducted by
NCASI representing 98% of the sludge generated by 204 mills in the U.S. in 1995.

L a n d A p p lic a tio n

12%

B u rn

'

L a n d fill/

O th e r

Lagoon

B e n e fic ia l U s e

51%

5 .5 %

R e c y c le / R e u s e
5 .6 %

3.9 Million Tons - Total Sludge Production

Figure 2: Final sludge disposal practices (NCASI, 1999).

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In 1995, according to NCASI, the pulp and paper industry produced a total of
3.9 million dry tons of sludge. Of this, 51% were landfilled, 26% incinerated, and 23%
were beneficially used. These numbers are slightly different from Carpenter and
Fernandez (2000) publication as they come from different sources and years.

Incineration of sludge serves the purpose of disposing the material to recover
energy for the paper making process. Unfortunately, the high moisture and ash content
of sludge make total combustion difficult. Modification of traditional incinerator
technology and mixing sludge with high amounts of bark is necessary in order to totally
incinerate the organic material. Before combustion, the moisture content of the material
needs to be reduced. A great deal of heat is necessary to burn sludge when it has high
moisture content (Mabee, 2001). Other, but less economical alternatives to incineration
include ethanol production by indirect combustion and pelletizing sludge as an
alternative fuel source.

Recycling options are based on the chemical or physical characteristics of the
sludge. Because sludge is a significant source of organic matter and nutrients, early
research focused on land application for enhancing growth of trees and crops. Land
application of sludge is the most popular disposal alternative for the pulp and paper
industry in countries such as the United States, Sweden, Finland, India, Brazil and
Canada (Alberta, British Columbia, Ontario, Quebec). The main problem identified in the
earliest trials was the low fertilization value associated with the sludge (NCASI, 1984a).
This problem was addressed by numerous pilot projects using discrete materials mixed
with sludge to be of beneficial use as soil amendment.
Another option to increase the fertilization value was composting mixed sludges,
most utilizing the aerated static pile method (Biofine Inc., 1998). Composting lowers the

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C content, which combined with high N feedstock decreases the C:N ratio. Several
composting facilities include wood ash in their feedstock mixture to decrease the
moisture content and increase the mineral content of the mix (Kunzler, 2001). However,
composting can be quite expensive (upwards of $30/ton) and thus economic success is
dependent upon market conditions (Pickell and Wunderlich, 1995).
Further recycling technologies are based on the physical characteristics of
sludge. The fibrous material can be used in the manufacture of ceramic and building
materials, such as cement, bricks and concrete. If sludge is used as filler or aggregate in
cement or concrete, the tensile strength increases. Sludge-amended material will not
crack as easily under freezing and thawing conditions. It could be used to construct
highways, buildings and bridges, providing a longer lifespan (Canning, 1999). Sludge
has been used beneficially as absorbent materials for industrial cleanups, hydromulch,
and animal beddings.

Land-applied sludge is a source of organic matter affecting physical properties of
the soil like aggregation, stability, bulk density, water holding capacity, and water
retention. Organic matter plays a fundamental role in the stabilization of soil and the
formation of pores (Khaleel et al. 1981; Metzger and Yaron, 1987; Tester, 1990; Hill and
James, 1995). These attributes are of importance in land reclamation and construction
projects.
Sludge has been used beneficially in several land reclamation projects in the UK
and U.S. Recovery of unusable land is enhanced by sludge application to areas where
plant growth is non-existent or limited, often due to previous industrial activities that have
introduced or brought to the surface substances which are unfavorable to plant growth.
In the UK and U.S., sludge has been applied to spoil mounds from abandoned
coalmines. Such locations tend to generate acidic run-off (as low as pH 3-4 in some

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cases) due to oxidation of pyrites in the colliery spoil (Webb, 2000). That means that the
absorptive activity and the buffering capacity of any calcium carbonate in the sludge is
particularly valuable. Sludge also has a much higher affinity to adsorb heavy metals than
typical kaolinite clay because of its high organic content. This characteristic is used in
another research project in the U.S. where sludge was utilized to build a slurry wall
around an old processing plant where zinc and lead contamination endangered
groundwater (Canning, 1999; Brown etal., 2003).
The clay like behavior of sludge is also of interest for landfill capping. The NCASI
has investigated the use of sludge as cover material on a daily, intermediate, and final
cover of varying thickness on industrial, municipal, and industrial/municipal waste
landfills. The most important physical property affecting the suitability of sludge as
material for the barrier layer is hydraulic conductivity. It describes the ratio of the flux to
the potential gradient of water (volume per time) (Hillel, 1998). Field hydraulic
conductivity studies were conducted at barrier layer test plots over eight years. At the
effective stress of approximately 5 kPa existing during the service life of the test plots,
sludge had a hydraulic conductivity of 4x1 O'8 cm/sec. The clay test plots had a hydraulic
conductivity of 1x1 O'6 cm/sec. The test results also showed that the barrier layers made
with paper mill sludge underwent no deterioration in performance during their service
life. After the eight year study sludge in the test plots appeared identical to fresh sludge,
which also suggests that the sludge had not degraded. In addition to the hydraulic
conductivity measurements, a dye tracer study was conducted. The study showed that
only one preferential flow pattern existed in the sludge barriers, and this flow path
appeared to be in a construction defect. In contrast, the clay barrier layers were riddled
with preferential flow paths, and thus had much higher hydraulic conductivity than the
paper mill sludge (NASCI, 1997). Some of the earth normally used to cap the daily
inputs can be replaced by sludge. The observation that sludge has properties similar to

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some clay soils has created particular interest in using sludge as landfill liner material
and as the hydraulic barrier layer in landfill covers. Results from previous studies are
summarized in Table 5.
Table 5: Residuals index properties and hydraulic conductivity of sludge used as barrier layer
from previous studies (NCASI, 2002).

Source

Andersland
and Laza
(1972)
Kraus et al.
(1997)
Zimmie and
Moo Young
(1993-1997)
NCASI
(1989)
Benson and
Wang
(1996)

W ater
Content1

Organic
Content

(% )

Ash
Content
(% )

Solids
Content

Specific
Gravity

Hydraulic
Conductivity3
(cm/s)

-

49-84

28-50

2.22.36

8.1x1 O'5 8.1x1 O'6
1.4x10'3 2.8x1 O'8

150-260

44-56

“

“

"

150-268

-

35-60

29-40

1.8-2.0

121-409

10-62

-

20-45

1.6-2.4

-

-

-

(%)

-

-

7.4x1 O'7 1,1x10'8
4 .2x 1 0'4 5.8x1 O'8
8 .3x10'7 9.9x1 O'9

Residuals
Type
Sorted
Organic
Residual
Primary and
combined
Primary and
combined
Primary and
combined
Primary and
combined2

1water content = (wet mass-dry mass)/dry mass
2tests conducted at effective stresses ranging from 5 kPa to 60 kPa
3sludge compacted similar to compacted clay

2.2

Case studies o f various applications
Sludge from paper manufacturing has been applied to agricultural and forestry

land to increase net primary productivity for decades. Numerous studies throughout
North America and Europe have highlighted the benefits associated with utilization of
sludge as soil amendment.
Intensive agriculture and nursery culture in the Niagara area of Ontario have
resulted in a high demand for organic soil amendments. Besides manures and peat
moss, organic-rich paper sludge and sludge-based composts could serve as substitute
soil amendments. In several studies, crop yield was investigated in relation to sludge
application (Bellamy et al., 1995). Tomatoes, cucumbers, and peppers were grown with

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separate and mixed primary, secondary and deinking sludge components. All growth
responses were related to N content in the sludges. Inhibited growth was observed with
primary and deinking sludge, which are low in N content. Secondary sludge, which is
rich in N, produced excessive growth. A blend of primary and secondary sludge enriched
with N fertilizer had a beneficial effect on vegetable growth in the greenhouse. In a
second greenhouse experiment with shrubs and an additional field experiment with corn
the growth of the species was correlated to the percent of N in the sludge soil mixture. In
conclusion, sludge utilization is constrained by N immobilization in sludge-treated
growing media or field soils, resulting in N deficiencies in plants. This could be overcome
by adding appropriate quantities of N fertilizer (Bellamy et al., 1995).
In Spain, three organic residues (olive mill sludge, municipal solid waste
compost, paper mill sludge) were used in a 3-year field experiment involving orange
production (Madejon et al., 2003). The application of compost and paper mill sludge
increased orange yield. Moreover, total carbon and humic substances significantly
increased in soils treated with all the organic amendments. Positive correlations between
enzymatic activities and total organic carbon were found for all treatments. However, a
clear inhibition of phosphatase activity was observed in soils treated with sludge. This
result indicates that repeated application of moderate amounts of organic amendments
has positive effects on the chemical and biochemical properties of the soil, as well as on
the orange yield (Madejon et al., 2003; Gagnon et al., 2001). Sludge amendment
promotes microbial growth and activity in the soil by improving carbon and water
availability. A measurable indicator for bacterial growth is the enzyme phosphatase,
which accelerates the hydrolysis and synthesis of organic esters of phosphoric acid and
the transfer of phosphate groups to other compounds. Phosphatase activates the
mineralization of organic phosphorous, releasing phosphate, which would otherwise not
be available.

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In Atlantic Canada, the amendment of sludge to organic-matter-depleted potatoproducing soils was investigated. One year after incorporating sludge at rates equivalent
to 0.5, 1.0, 2.0, and 4% organic matter in the plow layer of a gravelly loam soil, bulk
density had decreased with increasing rates of organic matter addition, while saturated
hydraulic conductivity and specific moisture content increased. The beneficial effects of
the organic matter treatment include 2.1 times delay in runoff initiation, and 23 and 71%
reduction in runoff and soil loss. Although the beneficial effects in soil and water
conservation are apparent, a minor drawback appears to be lower field soil moisture
content, which could be controlled by sludge application rates (Chow et al., 2003).
Forest land application is a particularly attractive use for this material because
many companies own forest lands that are in close proximity to mill sites where the
sludge is generated and would be consistent with the concepts of sustainable forestry
(NCASI, 2000). In one study, growth and yield of lodgepole pine and white spruce grown
on sludge-treated soil were measured. Primary and secondary sludge mixed in the ratio
of 1:2 was applied to marginal forestland at a rate of 80 t/ha per year. The resulting
seedling growth showed significant increases of up to 250% in both height and diameter
compared to control sites (Macyk, 1999; Mabee, 2001).
Effects of land-applied sludges on forest productivity have been shown to depend
to a great extent on their N content and availability. A study on productivity of
cottonwood, Douglas fir, Noble fir, and white pine seedlings grown in nursery beds
showed direct dependency on the C:N ratio (Henry, 1986). Growth responses to sludge
were positive with C:N ratios up to 20:1. Positive tree growth responses have been
reported for sludges having C:N ratios of 100:1 to 150:1 (Henry, 1991).
While the contribution of organic matter from sludge is often confounded by
effects on N availability, the importance of sludge as a source of organic matter has
been demonstrated on some sites. One study showed that land application of primary

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sludge (C:N 213) on a fertile alluvial site in Oregon increased initial cottonwood height
growth 41% above fertilized, control plots (Shields et al., 1986). Although greater initial
growth increases (68%) were obtained with a higher nutrient, primary:secondary sludge
mixture, respective increases in height growth after three years were 31% and 38% for
primary and mixed sludge treatments. This suggests that site factors related to organic
matter were more limiting than nutrients. Surface-applied sludge can also enhance soil
moisture retention and alter soil temperature due to its mulching effect. Positive effects
of surface-applied sludge increased tree growth were attributed to improved moisture
retention on a site in the Pacific Northwest (Henry, 1991). A study in Maine showed
reduced growth of red pine, Japanese larch, and black spruce seedlings due to lower
soil temperature brought about by surface-applied sludge (Kraske, 1992; NCASI, 2000).

2.3

Landfill applications
In numerous laboratory and field studies, some paper mill sludges have been

shown to possess engineering properties similar to clays. The use of paper mill sludge in
landfill construction was initially investigated by Stoffel and Ham (1979) and Pepin
(1984). Based on these promising studies, significant research has been done by NCASI
and others using sludges for construction of barrier layers in landfill final covers (NCASI,
1989; Genthe, 1993; Floess et al., 1995; Moo-young and Zimmie, 1996; NCASI, 1997).
These studies indicate that the hydraulic performance of barrier layers constructed with
sludge will be as good as, or better than, the performance of barriers with clay. The
e arlies t reported d a te for a sludge incorporated into a landfill c o v e r w a s

1990. This

disposal alternative has the potential to use large quantities of sludge, and may be
particularly advantageous to landfill operators in regions where paper mills exist and clay
sources are scarce or costly (NCASI, 1997).

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Hydraulic conductivity tests were conducted on 15 paper mill sludges of various
origins (NCASI, 1989). After compaction of the specimens at their as-received water
contents (120-409%) using standard Proctor procedures (ASTM D 698), rigid-wall
compaction-mold permeaters were used for hydraulic conductivity testing. The resulting
hydraulic conductivities ranged from 4.2x1 O'6 to 5.8x10"10 m/s. The low hydraulic
conductivity obtained for some of the paper mill sludges suggested that some sludges
may be viable for use in constructing barrier layers, which generally are required to have
hydraulic conductivities less than 1x1 O'9 m/s (Kraus et al., 1997).
Since 1990, more then 14 landfills in the U.S. have been closed with sludge as
the hydraulic barrier material. Landfill size ranges from 1.21 ha municipal landfill to a
12.1 ha industrial landfill. The combined sludges contained approximately 5% to 15%
secondary sludge. Barrier layer thickness ranged from 0.6 to 1.2 meter. In some cases,
the sludge was placed 25% thicker than the target thickness to account for
consolidation. Hydraulic conductivity ranges from 10'5 to 10'9 cm/sec. Overburden
thickness ranged from 0.08 to 0.6 meter. In several cases synthetic soil was used as
overburden material. This manufactured soil was made from low-quality local soil as the
base material. Sludge added to the soil improved desired soil characteristics such as
water retention and the ability to support vegetative growth (NCASI, 1997).
In Massachusetts, the Hubbardston municipal sanitary landfill used sludge as a
substitute low-permeability material for the final cap. The sludge applied to the landfill
originated from a small mill processing 100% waste paper, typically pre- and post
consumer ground-free ledger and book paper. The annual 12,000 dry tons of sludge
contain a high percentage of clay resulting in hydraulic conductivity of 6x1 O'7 cm/s.
Based on the results of the pilot study the design of the final cap was approved and a
0.76 meter layer of sludge was substituted for the normal 0.46 meter low-permeability
soil layer in the cap (Floess et al., 1995).

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In Michigan, MEAD Publishing Paper Division operates an integrated pulp and
paper mill producing approximately 400 t/day of dewatered combined sludge. Instead of
disposing the sludge at the company-owned industrial landfill, it was utilized as hydraulic
barrier material for the closure of Mead’s 3.64-ha Phase 2 landfill (Malmstead et al.,
1999).
Recent studies focus on geotechnical, biochemical and microbiological properties
of soil organic matter as sludge seems to have applications beyond landfill barrier layers.
It has been used as a topsoil amendment in the municipal landfill caps for the towns of
Wilton and Hadley (N.Y.). These projects indicate that the sludge amended topsoil
readily absorbs large quantities of rainfall, reducing infiltration to the barrier layer and
also holding water for vegetation growth during dry periods (Floess et al., 1995).
Being at the surface, cover systems exhibit the greatest change in temperature,
moisture and atmospheric pressure. On the other hand, the stability of the soil pore
system is one of the important properties that affect the ability of the soil to store and
transmit air, water, and solutes. Sudden wetting is an important factor that can modify
the number, shape, continuity, and size distribution of the soil (Gregorich et al., 1993).
Rapid wetting of a structurally unstable soil results in filling of the interaggregate pores
by microaggregates, reduced porosity, changes in the pore-size distribution, and a
decreased infiltration rate (Nemati et al. 2000). Organic matter plays a fundamental role
in the stabilization of soil and the formation of pores (Bolt et al., 1986; Chow, 2003) and
bulk density (Martens, 1992). When subjected to sudden wetting, sludge application can
improve the resistance of the amended soil to the destructive action of rapid wetting. On
comparatively smooth soil surfaces, the beating action of raindrops causes most of the
detachment. Where water is concentrated into channels, the cutting action of turbulent
flowing water detaches soil particles. As dispersed material dries, it may develop hard
crusts, which will prevent the emergence of seedlings and will encourage runoff from

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subsequent precipitation (Brady and Weil, 1999). These steps are the mechanics of
water erosion resulting in soil loss. Sludge has the potential to protect the soil during
critical periods of vegetation establishment and to prevent erosion on steep side slopes.
The processes of depletion and replenishment of soil moisture have received
considerable attention from agricultural scientists because of the dependence of plant
growth on soil moisture supply. The maximum amount of moisture that can be stored in
soil in the field and the degree of dryness to which plants can reduce the moisture
content of soil are the limits that determine the range of moisture available to plants
(Richards and Weaver, 1944). The effect of organic matter on soil moisture retention
became more and more an issue as soil and water quality and quantity became a
growing environmental concern. The consequences of soil amended with organic matter
were mainly studied in long term field experiments over the last decade. As the case
studies show, the research focus was on determining optimum application rates of
various organic amendments, including sludge, to improve soil conditions for plant
growth. There is no literature available on the effect of organic matter on soil moisture
retention investigated in laboratory experiments.
Laboratory experiments allow research of various parameters under defined
conditions. They can be performed on a small scale, in less time, and in a controlled
environment. This environment provides more flexible and cost efficient research without
negatively impacting the actual application site. The influence of each parameter on the
outcome can be adjusted in the lab and the consequences can be determined which has
the advantage of optimizing procedures for field conditions. The result can then be
applied to those field conditions and eventually lead to field applications.

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Chapter 3

Chemical and Physical Characterization

The chemical and physical characteristics of sludge vary with the manufacturing
process, and the type of effluent treatment employed. This research was designed to
evaluate the feasibility of utilizing two different sludges as soil amendments on a clay
topsoil layer in a landfill capping system, amendments designed to support vegetation
without causing an adverse environmental impact.
The first step in conducting the experimental part was to obtain a clay sample,
representative of the Prince George area. Two sludge samples have been obtained:
One from a Kraft pulping process and one from a bleaching chemo-thermo-mechanical
process (BCTMP). Sludge and soil samples have been distributed in smaller portions
and stored in a walk-in-freezer to prevent alterations. The structural composition of the
sludge samples was determined visually and with the scanning electron microscope. To
chemically characterize the sludge, pH, moisture content, ash content, C:N ratio, cation
exchange capacity, electrical conductivity, and salinity were determined. Selected
elements were quantitatively determined after closed vessel microwave acid digestion by
ICP-AES. Carbon and nitrogen were determined by total combustion. For physical
characterization bulk density, porosity, and water holding capacity were determined.
Water holding capacity was determined by gravity for three different treatments: original
sludge and soil samples, sludge-soil mixtures for BCTMP and Kraft mill sludge samples
(10:40, 20:30, 25:25, 30:20, 40:10), and sludge-soil layer systems for BCTMP and Kraft
mill sludge samples (1,2,3 layer systems). All samples were utilized as received.
Moisture retention curves were established for all three treatments using the pressure
plate experiment. Statistical analysis has been performed on all obtained data.

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Because sludge is composed mainly of organic fibers, standard procedures for
chemical analysis and methods for organic soils were applied. Methods and procedures
are outlined in this chapter. Results are summarized and discussed in chapter 4.

3 .1

M a te ria ls a n d m e th o d s

3.1.1

Sample collection
A clay type soil sample, representative of the Prince George area, was taken in

June 2002 at Tyner Boulevard/Ospika. The soil is similar to the Aleza Lake 1 - Orthic
Luvic Gleysol (Arocena and Sanborn, 1999). After removing the dried top layer from a
soil stockpile samples were taken from three different spots in the pile. The soil sample
was collected in a 20-liter bucket with lid and stored in the walk-in cooler (4°C) at UNBC.
Before usage the soil was mixed well in the bucket.
The two sludge samples are solid wastes from two different pulp and paper mills.
One sludge is from a Kraft pulping process and one from a bleaching chemo-thermomechanical pulping process (BCTMP). Both sludge samples were taken directly from the
filter press output. The sludge samples are representative samples from a pile of sludge
that was produced at that time. As pulping process conditions change the chemical and
physical sludge composition will vary.
The pulp mill sludge from the BCTMP was obtained on December 19, 2001. This
sludge sample was collected in two 20-liter buckets. Each of the buckets was half filled.
The sludge sample from these two buckets was then evenly distributed among four
buckets. After closing and labeling, the four buckets were placed in the -20° C walk-in
freezer at the University of Northern British Columbia (UNBC).
The pulp mill sludge from the Kraft process was obtained on January 23, 2002.
This sludge sample was also collected in two 20-liter buckets. Each bucket was half
filled with sludge and the material evenly distributed among four buckets. After closing

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and labeling, the four buckets were placed in the -20° C walk-in freezer at UNBC
together with the BCTMP samples (Merchant, 2001).

3.1.2

Sample storage
For further experiments, smaller amounts of the original sludge samples are

needed. Thus, 10 samples of each sludge of approximately 10 g were placed into ZipLock sandwich bags. The 20 bags were put together in a labeled box and stored in the
-20° C walk-in freezer at UNBC alongside with the sludge samples in the buckets until
needed.

3 .2

S lu d g e c h a ra cterizatio n

3.2.1

pH Determination
For pH determination with a pH-meter, a 1:4 sludge-to-liquid (wet weight/volume)

mixture was used. The liquid was distilled water. In a 250 ml beaker 5 grams of each
sludge sample was weighed and 20 ml of distilled water added. The sludge-water
mixtures were left for 30 minutes to equilibrate. After vacuum filtration the pH of the
milky, beige filtrate was measured with a pH-meter, ORION, model 420 A (Kalra and
Maynard, 1994).

3.2.2

Moisture content
The moisture content of both sludge samples was determined by weighing the

original sample in an aluminum dish, followed by drying the sludge in an oven and then
reweighing. The loss in weight (water) is expressed as a percentage of ovendried weight
(Kalra and Maynard, 1994). Drying of the wet sludge samples was conducted at three
different temperatures: 55 °C, 80 °C, 105 °C overnight, for a period of no less than 24

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hours. At higher temperatures, some components of organic matter may be volatilized. If
the sludge samples contain significant amounts of volatile compounds, the drying
temperature would be a source of variation in the results. For the BCTMP and Kraft mill
sludge the water content was conducted on 8 trials for the three temperatures. Data
obtained from the moisture content determination are listed in appendix B.

C alcu lation s:

(1)

Wd = Wt - W A,
where Wd is the weight of the dry sludge sample in g, Wt represents the
weight of the dry sludge sample and the weighing dish in g, and WAi
represents the weight of the weighing dish in g.

(2)

/■>

weight of sample wet (Ww) - weight of sample dry (Wd)
— ----- - x l 0 0 %
weight of sample dry (Wd)

0 = -------2-------------- ----------- ------- --------- 2--------------

where 0 is the moisture content in percent, Ww represents the mass of the
wet sample and Wd represents the mass of the dry sample. The mass
wetness (Ww), also called gravimetric wetness, is the ratio of the weight
loss in drying to the dry weight of the sample (mass and weight being
proportional) (Hillel, 1998).

3.2.3

Bulk density
The bulk density was determined for each treatment in the water holding capacity

and pressure plate experiment. The bulk density for each sample is obtained by dividing
the total dry mass over the total volume. The results for the original sludge and soil
samples are listed in Table 8.

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Calculation:
(3)

Db

Wd

weight of oven - dried sludge [g]

Vs

volume of sludge [cm ]

= -----= ------ - ----------------------------- —

. „ t

.

r ,

,,

= bulk density [g/cm3]

where Db is the bulk density in g/cm3, Wd represents the weight of the
oven-dried sludge in g and Vs represents the volume of the sludge in cm3
(Brady and Weil, 1999).
This calculation was applied to all experimental parts where bulk density was
determined.

3.2.4

Porosity
With the bulk density, the porosity can be calculated. Knowing the porosity

permits interpretation of the sludge behavior in terms of infiltration.
Calculation:

...
(4)

_
. Db
bulk density [Mg/m3]
P= 1
= 1-------------------------- 2 ----- - porosity [ ]
DP
particle density [Mg/m ]
Where, P is porosity; Db represents bulk density and Dp represents soil
particle density.

Assumption: Dp = 1.51 Mg/m3; particle density for organic soil (McGill, 2002)

3.2.5

Scanning Electron Microscopy and Energy Dispersive X-ray System
The scanning electron microscope (SEM) uses a beam of highly energetic

electrons to examine objects on a very fine scale. This examination can yield to
information as to structure and composition of the sludge samples.
Each of the two oven-dried sludge samples (105 °C) was fixed to an aluminum
peg with silver epoxy glue and sputter coated with a thin layer of gold (McGill, 2002).

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The sludge samples were observed under different enlargements to describe the sludge
appearance and compare the structure of the two samples. Semi-quantitative elemental
analysis was also provided on both sludge samples by using the energy dispersive X-ray
system (EDX) of the SEM (Philips Electron Optics, Philips XL 30). The results of the
elemental analysis depend on the spot in the sample analyzed.

3.2.6

Total Carbon and total Nitrogen (%C and %N)
For the determination of total carbon and nitrogen in the Kraft mill sludge and the

BCTMP sludge the oven-dried (105 °C) and ground samples (100 mesh) were used.
The method used to determine the carbon to nitrogen ratio is total combustion
(Brooks et al., 1989). It is based on the principle of oxidation of the carbon and nitrogen
in the sample to carbon dioxide, water, and nitrogen. The analysis has been carried out
with

an

elemental

analyzer

(Fisons

Instruments,

Fisons

NA1500

NC)

by

A. Esler, UNBC. The weight of the samples used was 2-3 mg.

3.2.7

Ash content
The ash content of the original sludge and soil samples was determined by

combustion at 525 °C (TAPPI standard test method T 211 om-93). Three replicates of
each sludge sample and the soil samples were weighed in crucibles and ignited in a
muffle furnace until the weight of the ash was constant.
C alculation:

(5)

ash % = (mass of ash [g] / mass of dry sample [g]) x 100%

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3.2.8

Elemental Analysis of selected inorganic components
The inorganic composition of BCTMP sludge and Kraft mill sludge was

characterized by using inductively coupled plasma atomic emission spectroscopy
(ICP-AES; Leeman, Labs PS1000-UV spectrometer). For the ICP analysis of BCTMP
and Kraft mill sludge, oven-dried (105°C) samples of each of the sludges were used.
Three replicates of each sludge sample were analyzed for macro- and micronutrients.

Sludge is mainly composed of organic matter. The sludge fibers are digested by
acid oxidation. Digestion of the sludge samples weighing approximately 0.2 g each was
accomplished by microwave acid digestion with 6 ml of HN03 (approximately 68%
concentration) and 1.5 mi H20 2 (approximately 37% concentration). This procedure for
organic matter digestion was developed at UNBC. The procedure gives a homogeneous
solution which is transferred to a 50 ml volumetric flask. The total volume of 50 ml was
made up with nanopure water. The samples were stored in Nalgene containers at 4°C.
Inductively coupled plasma - atomic emission spectroscopy (ICP-AES) was used
for elemental analysis of aluminum, boron, calcium, cadmium, cobalt, chromium, copper,
iron, lead, magnesium, manganese, molybdenum, nickel, phosphorus, potassium,
sodium, and zinc in the digested sludge samples.
ICP-AES is a multi-element analysis technique that will dissociate a sample into
its constituent atoms and ions and cause them to emit light at a characteristic
wavelength by exciting them to a higher energy level. This is accomplished by the use of
an inductively coupled plasma source, usually argon. A monochromator can separate
specific wavelengths of interest, and a detector is used to measure the intensity of the
emitted light. This information can be used to calculate the concentration of that
particular element in the sample.

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As there were no elemental analysis data available for the Kraft mill and BCTMP
sludge, the data from NCASI Sludge analysis (NCASI, 2002) was the basis for
estimating the concentration ranges for the standard calibration curves. Determination of
the concentration of each element in the sludge sample relies on the standard calibration
curve. Knowledge of possible concentration ranges of the element in the sludge sample
helps to determine appropriate standard concentrations.
For each element three different concentrations of calibration standards were
made up in 5% nitric acid (H N03). Samples of 5% nitric acid were used as blanks to
perform background corrections (appendix G).

3.2.9

Electrical conductivity and salinity
The 1:5 soil-to-water extraction method was used to determine electrical

conductivity and salinity of the BCTMP sludge, Kraft mill sludge, and soil sample (Kalrad
and Maynard, 1994). Fifteen grams of air-dried sludge and soil was transferred to a 250
ml Erlenmeyer flask and 75 ml of de-ionized water added. The stoppered flasks were put
on a reciprocating shaker, (Eberbach Corporation, Ann Arbor, Michigan) and the
mixtures shaken for 1 hour. The filtrates obtained after vacuum filtration were centrifuged
for 5 minutes at 10,000 rpm/16,000 g (centrifuge model: Flermle, Z382K). Electrical
conductivity and salinity was determined from the clear, pale yellow decanted filtrates of
the sludge samples and the clear, colorless decanted filtrate of the soil samples. The
pale yellow color of the sludge filtrates is induced by lignin. The conductivity instrument,
YSI Model 3100, was calibrated with 0.01 M KCI solution at 25 °C. The cell constant was
set to 1 at a measuring range of 0 - 49.99 mS/cm. For the conductivity measurements
the mode temperature compensated was chosen.
Conductivity and salinity were determined for three replicates of each sludge
sample and the soil sample.

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3.2.10 Effective cation exchange capacity (CECe), exchangeable cations
The barium chloride method was used to determine the exchangeable cations
and the effective cation exchange capacity for the BCTMP sludge, Kraft mill sludge, and
soil samples (Gillman and Sumpter, 1986). The soil sample was analyzed directly, but
the 2 sludge samples were milled using a Cyclotec mill and homogenized before
analysis to enable representative sampling. The soil sample was extracted at a ratio of
1.5 g to 15 ml extracting solution as per mineral soils. The BCTMP sludge was extracted
at 0.6 g to 15 ml as per high organic soils. The Kraft mill sludge sample had to be
extracted at 0.6 g to 30 ml extractant due to its very fibrous and absorbent nature (Clive
R. Dawson, 2003). The analysis was performed by the British Columbia Ministry of
Forests Research Branch Laboratory, Analytical Chemistry Section. Triplicate analysis
was conducted (appendix F).

3.2.11 Water holding capacity
The water-holding capacity (WHC) of sludge and soil samples can be determined
by a “soak and drain” method where water in saturated samples is extracted by gravity.
Water can also be extracted from saturated samples over a water potential range of 0 to
-1 0 kPa using a pressure plate (Tempe cells) or a tension table apparatus (Carter,
1993).

3.2.11.1

Gravity or European Method

To determine the water-holding capacity plastic columns of 7.0 centimeters
height with a diameter of 6.9 centimeters were used. One end of the column was
covered with 2-3 layers of cheese cloth. The column was filled % with sample and
tapped gently to compact the sample. The prepared columns were weighed empty and
when filled with sample. The height of the sample was also determined. The column

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enclosing the sample was placed in a vessel containing enough water to saturate the
sample. When the sample was saturated (24 hours), the vessel was removed and the
sample allowed to drain for 24 hours. The top of the column was covered loosely with
parafilm to minimize evaporation and a couple of small holes (needle) permit airflow.
When drainage was complete, duplicate samples were removed from the central portion
of each column for moisture content determination. These samples were dried in an
oven at 105 °C for 24 hours. This moisture content is approximately equal to waterholding capacity (Gomez et al., 1997; Harding et al., 1964).
The above described set up was used for three different treatments:
a) original sludge and soil samples
b) sludge-soil mixtures for the BCTMP and Kraft mill sludge samples
c) sludge-soil layer systems for the BCTMP and Kraft mill sludge samples.
The number of replicates varied depending on the experiment. The columns
were filled with original samples and various sludge-soil mixtures to a height of
approximately 4 centimeters.

For the sludge-soil layer systems, a total height of 6 cm was maintained for the 1,
2, and 3 layer system. The height of each sludge and soil layer was selected to maintain
the same total height within the various sludge-soil layer systems.

sludge
3rd layer
H

H

0

soil

H

height

2nd layer
1st layer

Figure 3: Outline for the sludge-soil layer systems.

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First, the bulk density and the water-holding capacity of the original sludge and
soil samples were examined. The original data are used for comparison. The same
procedure was applied to various mixtures of sludge and soil (10:40, 20:30, 25:25,
30:20, 40:10). The sludge was mixed with soil in a blender, Proctor Silex, 7 Blend
Master, on pulsation. The control sludge samples were treated in the same manner.
This procedure was also applied to sludge-soil layer systems, where each sludge
and soil layer has a different height, but the total height of the sample in the column
stays the same.
Calculations:
(6)

Sample volume:

V = (t t / 4 ) x d 2 x h

where d is the diameter of the column, 6.9 cm, and h is the height of the
entire sample in cm in the column. The sample volume is given in cm3.
(3)

Bulk density:

Db =

[g/cm3]
Vs

where Db is the bulk density in g/cm3, Wd represents the weight of the
oven-dried sludge in g and Vs represents the volume of the sludge in cm3
(Brady and Weil, 1999).

(7)

Gravimetric water-holding capacity at equilibrium (Gomez et al., 1997):

_ weight of sample wet - weight of sample dry ^
9
weight of sample dry

3.2.11.2

Pressure Plate Experiment

Through the application of pressure plate extractors the characteristic moisture
retention curve can be developed for each soil type. The curves relate the soil suction, at
which moisture is held by the soil, to its moisture content. This relationship is important

41

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in studies of soil moisture movement and of quantity and availability of soil moisture for
plant growth (Soilmoisture Equipment Corp., 2001).

To determine the moisture retention curves, the sample preparation described
under 3.2.11.1 was used. The column was filled with sample to a height of 1 cm. The
sample was gently compacted with the bottom of a beaker and the height remeasured.
The prepared columns were weighed empty and when filled with sample. The column
enclosing the sample was placed directly on the ceramic plate and placed in a vessel
containing enough water for 24 hours to saturate sample and ceramic plate. Saturated
ceramic plate and sample are placed in the pressure plate extractor and left until
equilibrated at the desired pressure. Gravimetric moisture content was determined after
drying the sample in an oven at 105 °C for 24 hours.

d)

1600G1
5 -B a r P re ssu re
P la te E x tra c to r

0776L60
C o n n e c tin g H ose

^y/

C o n n e c tin g H o s e

1500G 1
1 5 -B a r P re ssure
P la te E x tra c to r

Jj

0 779G 1
C o n n e c tin g H ose

0500FG _
C o m p re s s o r

F igure 4: P re s s u re p la te e x tra c to r s e t up (S o ilm o is tu re E q u ip m e n t C o rp ., 2 0 0 1 ).

For the moisture retention curves of the original sludge and soil samples, the
moisture content of 11 pressure points was determined (0.1 ;0.2;0.3 ;0.4;0.5;0.7;1.0;2.0;

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5.0; 10.0;15.0 bar). For each run, one Kraft mill, BCTMP sludge and soil sample was
placed on the pressure plate. A 1 bar ceramic plate was used for pressures up to 1 bar.
For the pressures 1.0 and 2.0 bar a 3 bar ceramic plate was used. A 15 bar ceramic
plate was used for 5.0, 10.0, and 15 bar pressure.
Moisture content was determined from the entire sample when equilibrium was
reached.
Calculations:
(8)

Volumetric water-holding capacity at equilibrium (Brady and Weil, 1999):

weight of sample wet - weight of sample dry
5-----------------weight of sample dry

WHCV= ----- - -------------

(9)

^

xD b

x 100%

Available water (Brady and Weil, 1999):
field capacity water content (0.3 bar)
- wilting point water content (15.0 bar)
=

available water

The above described set up was also used for sludge-soil mixtures using BCTMP
and Kraft mill sludge samples. The mixtures were prepared as described in 3.2.11.1. For
the moisture retention curves of the sludge-soil mixtures the moisture content of 9
pressure points was determined (0.1;0.3;0.5;0.7;1.0;5.0;10.0;15.0 bar). At 0.3 and 15
bar, three replicates of each of the mixtures were measured, and from the average the
available water was calculated. Two trials for each mixture were performed at 1.0 bar.
Using the same set up as before, the moisture retention curves for sludge-soil
layer systems for the BCTMP and Kraft mill sludge samples were determined. The same
layer systems as described in 3.2.1.1 were prepared. The pressure points analyzed

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were 0.5, 1.0, and 5.0 bar. When equilibrium was reached each layer was split in half for
moisture content determination.

3.2.12 Statistical Analysis
Statistical analyses were performed on all data except the semi-quantitative
results from the energy dispersive x-ray analysis. Microsoft Excel was used to determine
average, standard error, and standard deviation. Error analysis was carried out by using
the method of propagation of random errors for the gravimetric and volumetric water
holding capacity data.
Random or statistical errors are unpredictable errors resulting from limited
precision of the measuring instrument and minor uncontrollable variations in the
operation of the equipment (Am, Ad, Ah). However, random error is not correctable and
the degree of uncertainty in measurements is indicated by derivations of the
experimental results. The errors expressed as ± ADb, ± AWHCg and ± AWHCV represent
the uncertainty in the quantity of interest in terms of confidence limits. Random error is
reduced by good tools and a large sample size.

Calculation:
(10)

For F = axyz (or axy/z or ax/yz or a/xyz),
A2( F ) _ A2(x)
F2

x2

A2(y )

A2(z)

y2

z2

where a,x,y,z are actual values and F represents the uncertainty in the
final result (Shoemaker et al., 1996).

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Chapter 4

Results and Discussion

The two major aspects for reusing sludge are its chemical and physical
characteristics. Sludge samples from BCTMP and Kraft mill processing were compared
and their water holding effect on a clay type of soil examined. Analysis was conducted
following the methods described in chapter 3.

4.1

Baseline characteristics
The BCTMP sludge sample in Figure 5 appeared as soft pellets and clumps of

fibers of medium to dark brown color. The sludge pellets contained smaller pieces of
white-yellowish wood fibers (0.5-1 cm length). The Kraft mill sludge in Figure 6 appeared
in lumps of fibers in a bi'own-beige color and contained fewer but larger pieces of darker
brown wood fibers (2-3 cm length).
The micrographs in Figure 7 and 8 show the sludge samples on an enlarged
scale. The Kraft mill sludge sample appears to be more homogeneous in its fiber
structure. The BCTMP sludge sample is composed of a broader variety of fibers and
wood pieces.
The difference in structure and aggregation of the sludge and soil samples were
visually inspected. The soil sample had a finer texture than the sludge samples. The
Kraft mill sludge sample has the coarsest texture. This is reflected in the bulk density
and porosity results (Table 8). Both sludge samples have a lower bulk density than the
soil. Bulk density indicates how easily a soil will till, how easily water will infiltrate, how it
will hold water, and its suitability for growing plants. There is more pore space available
to be filled with water in the sludge samples than in the soil.

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FIGURE 5: BCTMP sludge (1:1)

FIGURE 6: Kraft mill sludge (1:1)

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F IG U R E 7: SEM micrograph of BCTM P sludge (15x).

F IG U R E 8: SEM micrograph of Kraft mill sludge (15x).

47

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When preparing the sludge soil mixtures, the original sludge and soil structure
was changed by using a blender. The sludge and soil particles were separated into more
individual aggregates. The arrangement of aggregates gives the soil its structure.
However; soil particles filled the void space in the sludge samples. This is partially due to
the original sludge moisture content and the blending. After soaking and draining the soil
sludge layer samples, it was observed that the soil particles on the interface filled the
void pore space of the sludge. This change in aggregates increased the degree of
stability. When the sludge soil layer samples were taken out of the plastic columns, they
resisted sliding and crumbled less than the original soil sample. Increasing stability of the
topsoil layer is especially desirable at the site slopes.

4.2

Chemical characterization

4.2.1

General properties
A variety of properties are used to characterize sludge, including pH, moisture

content, ash content, C:N ratio, cation exchange capacity, electrical conductivity, and
salinity. The results are summarized in Table 6 and compared to previous studies.

Table 6: Properties of B C TM P and Kraft mill sludge compared with previous data.

component

n

unit

BCTMP

Kraft mill

literature

pH

2

-

6.95

8.25

6.43 a

moisture content

8

%

164 ± 1.78

165 ±3.41

121 - 409 b

ash content

3

%

4.40 ±0.15

4.40 ± 0.23

10 - 62 b

C:N

4

-

52:1

43:0

100:1; 300:1 c

C EC

3

cmol+/kg

35.25 ±0.12

19.70 ±0.04

NAd

electrical conductivity

3

pS/cm

1466

241

1120 a

salinity

3

ppt

0.8

0.1

NAd

aThe data were indirectly calculated based on a 3:1 primary to secondary sludge
ratio (Clear Lake Ltd., 1993).
bNCASI, 2002; cNCASI, 2000; dNA = not available

48

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With a pH of 6.95 the BCTMP sludge is neutral. The Kraft mill sludge with a pH of
8.25 is basic. The calculated literature value is slightly acidic with a pH of 6.43 (Clear
Lake Ltd., 1993).
The moisture content represents the average of 8 samples, oven-dried at 55°C,
80°C, and 105° C for 24 h until constant weight (± 0.2 g). The BCTMP sludge sample at
80° C represents the average of 6 samples. Raw data, standard deviation and standard
error are presented in Table (21-23) for Kraft mill and Table (24-26) for BCTMP sludge
(appendix B). The difference in moisture content determination at three different
temperatures for both sludge samples was small, which indicates the low presence of
volatile compounds. The larger standard errors for the Kraft mill sludge sample (± 3.41 at
105° C) compared to the BCTMP sludge sample (± 1.78 at 105° C) indicates a broader
variance around the average. This is a result of a less homogeneous sample. The
moisture content of both samples is alike and falls into the lower range of the literature
value.
The ash content for both sludge samples is 4.40% and represents the average of
three samples. The standard error for the BCTMP sludge is ± 0.15%, and ± 0.23% for
the Kraft mill sludge (Table (28), appendix D). Compared to the soil with 95.5% ash
content the sludge samples are high in organic matter expressed in the low percentage
of ash content. The reference range of the ash content is 10 to 62%. The sludge
samples are under the minimum value, which means, they are higher in organic matter.
Raw data are presented in Table (28), appendix D.
The C:N ratio for BCTMP sludge is 52:1 by mass. For Kraft mill sludge it is 43:0.1
by mass. Raw data are presented in Table (27), appendix C. The actual nitrogen content
in the BCTMP sludge could enhance vegetation growth on the final cover layer of a
landfill. However, because of the very small amounts of nitrogen present in the sludge,

49

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the soil-type of sludge mixture is important at as well as additional fertilization
possibilities to promote plant growth in landfill cover amended with sludge.
The cation exchange capacity for BCTMP sludge is 35.35 cmol+/kg and 19.70
cmol+/kg for Kraft mill sludge (Table 6). There is almost double the amount of
exchangeable cations available in BCTMP sludge. In the soil sample the CEC is 15.25
cmol+/kg. Raw data are presented in Table (31), appendix F. Normal CEC ranges in
soils would be from < 3 cmol+/kg to > 25 cmol+/kg (Ross, 2003). Cations retained
electrostatically are easily exchangeable with other cations in the sludge/soil solution
and are thus easily available for plant uptake. The CEC is pH dependent. Addition of
sludge material will likely increase the soil’s CEC.
The electrical conductivity of BCTMP sludge (1466 pS/cm) is 31% higher than
the literature value with 1120 pS/cm (Table 6). The conductivity of the Kraft mill sludge is
78% lower than the literature value. The electrical conductivity is a measurement of a
solution’s ability to conduct electric current. As the ability of a solution to conduct electric
current depends upon ions, there are more ions in the BCTMP than in the Kraft mill
solution. Conductivity is also an indirect measurement of salt content. The measured
salinity of BCTMP is 0.8 ppt and of Kraft mill sludge 0.1 ppt. These results are consistent
with the conductivity measurements.

4.2.2

Elemental analysis
The main elements found in both sludge samples by energy dispersive x-ray

analysis (Table 29 and 30, appendix E) are carbon and oxygen as they are the skeleton
of the cellulose fibers. The carbon to oxygen ratio of Kraft mill sludge is 2.65:1, and
1.53:1 for the BCTMP sludge. The section of the BCTMP sludge analyzed under the
microscope showed that it contains sodium, silicon, sulfur, potassium, and calcium. The
section of the Kraft mill sludge analyzed under the microscope showed that it contains

50

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neither sulfur nor potassium. Kraft mill sludge contains double the amount of sodium
than BCTMP sludge. BCTMP sludge contains approximately four times more calcium
than Kraft mill sludge. These results are semi-quantitative and represent only a section
of the sludge sample on the peg.

In both sludge samples, the levels of macro- and

micronutrients were

established. In each sludge sample, 17 elements were quantitatively determined after
closed vessel microwave acid digestion by ICP-AES. These elements include the
macronutrients K, Ca, Mg, and P. The other macronutrients S and N were not
determined by ICP-AES. All of the micronutrients were determined except chloride.
Results are summarized in Table 7 (Table 32, appendix G). The resulting concentrations
for all elements are in the lower range of the concentrations determined by NCASI
(NACSI, 2000). These results support the findings from NCASI that pulp and paper mill
sludge is in general low in potential environmental contaminants.
Both types of sludge can provide the nutrients for plant growth. The Kraft mill
sludge has lower concentrations of B, K, Mg, Mo, and P than required for plant growth
(Barak, 1999). The concentrations for Ca, Co, Fe, Mn, Ni, and Zn are higher than the
typical requirements for plant growth. BCTMP sludge differs from Kraft mill sludge. The
concentrations of B, K, Na, Ni, P, and Pb are higher in BCTMP sludge while
concentrations of Cu, Mg, and Mn are lower in BCTMP sludge (Table 7).
Micronutrients are as important for plant growth as macronutrients but in lower
concentrations. Whether a macronutrient or micronutrient, the most growth-limiting
nutrient will limit growth, no matter how favorable the nutrient supply of other elements
is. All essential elements are absorbed by the plants from soil solutions, as either cations
or anions, thus soil pH is an important factor to determine, as the ionic charge of the
elements depends on the surrounding pH.

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Table 7: Summary of results for the elemental analysis in oven-dried (105°C ) Kraft mill and
B C TM P sludge samples determined by IC P-A ES and literature data.

Element

Symbol

Kraft Mill
[mg/kg]

BCTMP
[mg/kg]

NCASI1
[mg/kg]

Nutrients 2
[mg/kg]
n/a
20
5,000

Aluminum

Al

702

295

590 - 59,000

Boron
Calcium
Cadmium
Cobalt

0.672
5931
0.088
0.582
4.97

62.0
7936
0.232
1.491
13.52

<1 -4 9 1
2 8 0 -2 1 0 ,0 0 0
<0.09 - 56
0 -9 .7

Chromium

B
Ca
Cd
Co
Cr

3 .0 - 2 ,2 5 0

n/a
n/a

Copper

Co

7.87

Iron

Fe
K

14.51
587

3 .9 - 1 ,5 9 0
97.1 - 10,800

6
100

1 2 0 - 10,000

Potassium
Magnesium

72.8
1795

478

2 0 0 - 19,000

10,000
2,000

28.6
*BDL

1 3 - 2 ,2 0 0
< 2 .5 - 1 4 .0

0.1

162

904

1.819

8.088

300 - 66,700
1 .3 - 1 3 3

0.1

932
*BDL
28.4

1 0 - 2 5 ,4 0 0
<0.05 - 880
1 3 - 3 ,7 8 0

2,000
n/a
20

Mg
Mn
Mo

89.0
*BDL

Nickel

Na
Ni

Phosphorus
Lead
Zinc

Pb
Zn

41.2
4.09
30.5

Manganese
Molybdenum
Sodium

P

312
277

n/a

50
n/a

1 NCASI 54 Mill survey (NACSI, 2000)
2 Typical concentrations sufficient for plant growth (Barak, 1999)
* B elow de te ctio n lim it

n/a = not a p p lica b le

The limiting growth factor of sludge is the low level of nitrogen. The nitrogen
concentrations in pulp mill sludge are ranging from 1.1 g/kg to 59 g/kg (NCASI, 2000).
Extensive research has been conducted in the past to overcome this disadvantage of
the sludge amendment. Compounds rich in organic nitrogen like manure, compost, and
biosolids were mixed with sludge and applied to agricultural land. Some of these studies
are mentioned in chapter II. Most landfills use compost produced onsite as fertilizer for
vegetation growth. The growth and appearance of plants varies considerably from one
species to another and even within species, depending on the environment. Alfalfa
utilizes 272 kg of nitrogen and yields 25.4 t/ha. Clover-grass utilizes only 136 kg of
nitrogen and yields 15.3 t/ha (Tisdale et al., 1985). In accordance with the vegetation

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applicable to landfill restoration plans and site climate, nitrogen sources need to be
added in quantities that will meet the requirements of the plants.

4.3

Physical characterization

4.3.1

Bulk density and porosity
BCTMP sludge has a higher bulk density with 0.094 Mg/m3 than Kraft mill sludge

with 0.054 Mg/m3. The different aggregation of the two sludge samples causes different
results in porosity. Kraft mill sludge has a coarser texture than BCTMP sludge. This
results in lower bulk density and higher porosity. The clay type soil has the highest bulk
density with 0.827 Mg/m3 and the lowest porosity. Data are summarized in Table 8.
Table 8: Bulk density and porosity of BCTMP and Kraft mill sludge.
Assumption: Dp = 1.51 Mg/m3; particle density for organic soil (McGill, 2002).
sample

Bulk density [Mg/m3]

Porosity

Kraft mill

0.054

0.964

BCTMP

0.094

0.937

Soil

0.827

0.452

These results support the observations under 4.1.

4.3.2

Water holding capacity by gravity
Data obtained from the bulk density and water holding capacity determination for

Kraft mill and BCTMP sludge and soil are listed in appendix H. In Table 9, the average of
the moisture content determination (=WHCg) of the duplicates of all dried samples is
summarized.
The Kraft mill and BCTMP sludge samples have a bulk density approximately
one order of magnitude lower than the clay type soil sample. The bulk density
determined for the blended sludge samples is lower than for the original samples.

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Table 9: Bulk density and gravimetric w ater holding capacity obtained from
original and blended Kraft mill and BCTMP sludge and soil sample.

sample
Kraft mill, blend
BCTM P, blend
Kraft mill
BCTM P
Soil

bulk density
[g/cm3]

(n=5)

± se

0.033
0.063
0.054
0.095
0.827

0.006
0.002
0.001
0.002
0.005

WHCg

± se

[%]
710
520
509

(n=5)

393
32

9.64
4.10
6.68
6.90
0.61

The gravimetric water holding capacity is lowest for the soil sample and highest
for the blended Kraft mill sludge sample. The BCTMP sludge sample has approximately
12 times and the Kraft mill sludge sample approximately 16 times more water holding
capacity than the soil sample. The data obtained in this part of the experiment
demonstrate that different structures and pore size distributions result in very different
water holding capacity.
In Table 10 and 11 the bulk density and moisture content on a weight basis
(=WHCg) average of dried samples of various sludge-soil mixtures is summarized. Data
obtained from the bulk density and water holding capacity determination for Kraft mill
and BCTMP sludge-soil mixtures are listed in appendix H. The original sludge sample
was mixed with 10, 20, 25, 30, and 40 mass percent of soil using a blender (Table 10
and 11). The original sludge was blended and used as reference. For both sludge
samples, the bulk density increased with higher percentage of soil in the sludge-soil
mixtures. The water holding capacity decreased with higher amounts of soil in the
mixture. The BCTMP sludge-soil mixture 10:40 has the highest bulk density and the
lowest water holding capacity. By comparing the sludge-soil mixtures the 25:25 mixture
doubles in water holding capacity compared to the 10:40 mixtures. Comparing the
sludge-soil mixtures with the lowest amount of sludge added (10:40) and the water

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holding capacity of the clay type soil, the water holding capacity doubles with Kraft mill
sludge and increases by two thirds with BCTMP sludge.
Table 10: Bulk density and gravimetric water holding capacity obtained from
various Kraft Mill sludge-soil mixtures.

sample

Kraft mill/soil 10:40
Kraft mill/soil 20:30
Kraft mill/soil 25:25
Kraft mill/soil 30:20
Kraft mill/soil 40:10
Kraft mill blend

bulk density

± se

WHCg

± se

[g/cm3]

(n=3)

[%]

(n=6)

0.343
0.157
0.145
0.098
0.055
0.033

0.005
0.015
0.006
0.004
0.001
0.001

65
139
145
251
447
710

4.74
11.95
11.73
17.31
19.44
9.64

Table 11: Bulk density and gravimetric water holding capacity obtained from
various BC TM P sludge-soil mixtures

sample

BCTMP/soil 10:40
BCTMP/soil 20:30
BCTMP/soil 25:25
BCTMP/soil 30:20
BCTMP/soil 40:10
B C TM P blend

bulk density

± se

WHCg

± se

[g/cm3]

(n=3)

[%]

(n=6)

0.499
0.311
0.256
0.181
0.117
0.063

0.008
0.016
0.011
0.006
0.003
0.002

52
87
107
178
294
521

1.19
5.48
3.67
6.03
7.77
4.10

Data obtained in this part of the experiment demonstrate the effect of the sludge
amendment. Adding higher amounts of sludge results in decreasing bulk densities and
increasing water holding capacities. The same effects were found when sludge at
different rates was amended to gravelly loam soil in a field study (Chow et al., 2003). In
this study, results on water-stable aggregates revealed that the organic matter in the
pulp fib er com bined s m a lle r a g g re g a te s to form la rg e r a g g re g a te s , resulting in a la rg er

proportion of macropores as compared to micropores. The original sludge samples
(Table 8) have a higher bulk density and a lower water holding capacity compared to the
blended samples. Blending the sludge affects the fiber structure, resulting in different
bulk density and water holding capacity.

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Another alternative to examining sludge-soil mixtures was to look at packing
sludge and soil in layers (Figure 4). By keeping the total height of the sample the same,
the height of each sludge and soil layer varied between the 1, 2 and 3 layer systems. In
Table 12 and 13, the average of the gravimetric moisture content determination
(=WHCg) of dried samples of sludge-soil layer systems are summarized. Data obtained
from the bulk density and water holding capacity determination for Kraft mill and BCTMP
sludge-soil layer systems are listed in appendix H.
The water holding capacity of the bottom layer of sludge increased for the 2 and
3 layer system compared to the 1 layer system. For the 1 layer system, the water
holding capacity for the sludge is approximately 10 times higher than in the soil. The
same effect can be observed for the soil layer in the 2 and 3 layer systems. This is
consistent with reduced water transmission being induced by surrounding sludge layers.
The water holding capacity of the soil layer stays between 36 and 39% in all three
systems.

Table 12: Bulk density and gravimetric water holding capacity of 1, 2,
and 3 layer systems of Kraft mill sludge.

Bulk density

± se

WHCg

± se

[g/cm3]

(n=3)

[%]

(n=6)

Sludge 1
Soil 1
weighted average

0.084
0.916

0.014
0.016

332
39

42.0
0.60

Sludge 1
Soil 1
Sludge 2
Soil 2
weighted average

0.061
0.840
0.073
0.941

Sludge 1
Soil 1
Sludge 2
Soil 2
Sludge 3
Soil 3
weighted average

0.077
0.677
0.114
0.810
0.095
1.019

sample

Kraft mill
1 layer

Kraft mill
2 layer

Kraft mill
3 layer

185
0.002
0.050
0.004
0.059

487
38
494
39

16.5
0.59

11.4
0.23

264
0.006
0.009
0.012
0.024
0.003
0.099

486
36
380
38
431
38

8.60
0.65
15.9
0.67
26.9
0.36

235

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Table 13: Bulk density and gravimetric w ater holding capacity of 1, 2,
and 3 layer systems of BCTMP sludge.

Bulk density

± se

WHCg

± se

[g/cm3]

(n=3)

[%]

(n=6)

Sludge 1
Soil 1
weighted average

0.094
0.897

0.001
0.011

378
40

3.69
0.46

Sludge 1
Soil 1
Sludge 2
Soil 2
weighted average

0.097
0.681
0.126
0.795

Sludge 1
Soil 1
Sludge 2
Soil 2
Sludge 3
Soil 3
weighted average

0.121
0.850
0.121
0.790
0.134
0.742

sample

B CTM P
1 layer

B CTM P
2 layer

BCTM P
3 layer

209
0.006
0.009
0.005
0.010

476
41
434
40

44.9
0.53
14.6
0.55

248
0.001
0.034
0.013
0.009
0.009
0.007

394
42
356
42
424
41

7.23
0.62
13.2
0.51
17.6
0.63

217

Comparing the total water holding capacity calculated by weighted average, the 2
layer system has the highest water holding capacity with 264 % for Kraft mill sludge and
248 % for BCTMP sludge. The 3 layer system has a total water holding capacity of
235 % for Kraft mill sludge and 217 % for CTMP sludge, and the 1 layer system is lowest
with 185 % for Kraft mill sludge and 209 % for BCTMP sludge. Adding a third layer of
sludge and soil resulted in a lower total water holding capacity than in the 2 layer
system. This could be due to each layer decreasing in layer thickness to maintain the
same total height. The increase in water holding capacity in the sludge layer in all three
layer systems refers to the sludges capability to retain water. In the three layer system
the second sludge layer has a lower water holding capacity than the first and third layer.
This second sludge layer is enclosed by soil layers. The soil particles filled some of the
voids in the sludge reducing water holding capacity of the sludge.

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The water holding capacity in the layer systems is similar to the 30:20 sludge-soil
mixtures and lower than the original sludge samples. The slightly higher bulk density in
the second sludge layer of the 2 and 3 layer system are due to soil particle attached to
the sludge fibers.

4.3.3

Pressure plate experiment
When equilibrium was reached water holding capacity or moisture content was

determined for the sludge and soil samples at different pressures. Data obtained for bulk
density, moisture content and error analysis are listed in appendix I. The water holding
capacity is expressed on a volume basis using equation (8). For 11 samples of BCTMP
sludge and for 11 samples of Kraft mill sludge the average bulk density is
0.14 g/cm3. The average bulk density for 10 samples of soil is 1.37 g/cm3. Compared to
the original samples (Table 8) bulk densities determined in the pressure plate
experiment are higher. A summary of the volumetric moisture content data with random
errors is presented in Table 14.
BCTMP sludge can hold the highest amount of water. It includes the available,
unavailable, and gravitational water. The soil holds the lowest amount of water. The
observed water holding capacity is similar to the general literature value of 52% for clay
loams (Klocke, 1996). At field capacity, BCTMP sludge has moisture retention of 53.7%,
Kraft mill sludge has 36.7%, and soil has 39.2%. The water held between field capacity
and wilting point available water is most important for vegetation. Plants can use
approximately 50 percent of the available water without stress, as the water is retained
by capillary forces. The total amount of available water in BCTMP sludge is 4 times
higher than in soil and Kraft mill sludge is 7 times lower than in soil. This water storage

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capacity of BCTMP sludge can be used beneficially to increase the water holding
capacity in soils.

The moisture retention curves obtained for the sludge and soil samples are
shown in Figure 9 and 10.

Table 14: Volumetric moisture retention curve data with random errors for B C TM P sludge, Kraft
mill sludge, and soil (n=1).

pressure

Field capacity

BCTMP

0.1

49.6

0.2

52.8

0.3
0.4

53.7

0.5
0.7
1
2

Wilting point
Available water

moisture % vol.

[barl x (-1)

49.5
46.1
45.5
45.4

5
10

46.5
48.9
40.2

15

37.2
16.5

± A WHCV Kraft mill ± A WHCV
1.01
1.08
1.10
1.01
0.94
0.93
0.93
0.95
1.00
0.82
0.76

58.8
42.3
36.7
38.5
33.5
33.4
32.1
30.4
38.1
35.6
36.1
0.6

1.20
0.86
0.75
0.79
0.68
0.68
0.66
0.62
0.78
0.73
0.74

Soil

± 4 WHCV

52.2

1.07
0.92
0.80
0.92
0.65
0.72
0.78
0.74
0.82
0.72
0.71

45.1
39.2
4 4.9
31.8
35.3
38.0
36.3
40.3
35.0
34.7
4.5

The pressure plate experiment was used to determine moisture retention curves
for soil samples. The soil is different in structure from the two sludge samples. The
sludge samples are less homogeneous and a broader variety of pore sizes is involved.
The various pores are distributed unevenly. This affects the sample preparation and is
expressed in the random errors. As the experimental process to obtain a data set for one
pressure takes 4 days, no replicates have been conducted. The above information is
used for comparison with sludge-soil mixtures and sludge-soil layer systems.

59

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BCTMP
Kraft mill
Soil

pressure [bar] x (-1)

Figure 9: Moisture retention curves for BCTM P sludge, Kraft mill sludge and soil from 0.1 to
15 bar x (-1) with random errors.

BCTMP
Kraft mill
Soil

0.5

2.5

pressure [bar] x (-1)

Figure 10: Moisture retention curves for BC TM P sludge, Kraft mill sludge and soil from 0.1 to
2.5 b a rx (-1) with random errors.

60

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Examination of the moisture retention curves of the sludge-soil mixtures support
the findings from several field experiments, that organic matter increases the water
retention in soil (Foley and Cooperband, 2002). BCTMP sludge-soil mixture 25:25 and
Kraft mill sludge-soil mixture 30:20 have the highest volumetric moisture retention at
-0.1 bar. The sludge-soil mixture 20:30 for BCTMP sludge, and the original Kraft mill
sludge have the lowest volumetric moisture retention at -0.1 bar (Figures 11 to 14).
Compared to the soil sample at field capacity (39%) and permanent wilting point (35%)
Kraft mill sludge-soil mixtures increased volumetric moisture retention more than
BCTMP sludge-soil mixtures. Wei et al. (1985) showed that biosolids additions increased
water retention at low tensions in a silty clay loam soil, suggesting an increase in larger
pores. Recently, Zibilske et al. (2000) showed that multiple applications of paper mill
residuals significantly increased soil moisture holding capacity. Municipal solid waste
compost addition to sandy soil increased water retention, but did not change plant
available water (Turner et al., 1994).

Volumetric moisture content and random errors are summarized in Table 15 for
BCTMP sludge-soil mixtures and in Table 16 for Kraft mill sludge-soil mixtures. Data for
bulk density, moisture content, and error analysis are provided in appendix I. Bulk
density of soil decreases with increasing amounts of sludge added. Overall the BCTMP
and Kraft mill sludge-soil mixture bulk densities are similar (Tables 54 to 67, appendix I).
Both sludge samples have through all sludge-soil mixtures an outlier at 0.5 or 0.7
bar. The original sludge and soil samples show an outlier at 0.4 bar (Figure 9 and 10).
This is not referring to a change of pressure plates as the experiment was conducted
with a 1 bar ceramic plate up to and including 1 bar. At this point data collected are not
sufficient to provide an explanation for the outliers. Further experiments with smaller
pressure increments are necessary to explain the outliers.

61

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— • — original
— □— blend
X

40:10

— A — 30:20
•--X--- 25:25
— •-- 2 0 :3 0

XX

g

. .. ...

Q-

0.0

10.0

4.0

2.0

12.0

14.0

16.0

pressure [bar] x (-1)

F IG U R E 11: Moisture retention curves for BCTM P sludge-soil mixtures from 0.1 to 15 bar x (-1).

original
blend

A

30.20

X

25:25

•-- 2 0 :3 0

.60

H

10:40

£50

♦

0.0

0.5

2.0

2.5

pressure [bar] x (-1)

F IG U R E 12: Moisture retention curves for BCTM P sludge-soil mixtures from 0.1 to 2.5 bar x (-1).
(Enlarged graphs with error bars see appendix I, Figure 27 - 30)

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

— 4 — original
— □— blend
— X — 40:10
A

30:20

X

25:25

-• --2 0 :3 0
H

0.0

4.0

2.0

6.0

10.0

10:40

14.0

12.0

16.0

pressure [bar] x (-1)

F IG U R E 13: Moisture retention curves for Kraft mill sludge-soil mixtures from 0.1 to 15 b a rx (-1).

♦ — original
□ — blend
X —

40:10

X

25:25

• -- 2 0 :3 0

B

0.0

0.5

2.0

10:40

2.5

pressure [bar] x (-1)

F IG U R E 14: Moisture retention curves for Kraft mill sludge-soil mixtures from 0.1 to 2.5 b a rx (-1).
(Enlarged graphs with error bars see appendix I, Figure 19 - 22)

63

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Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Moisture-retention-curves for BCTMP sludge-soil-mixtures

Table 15: Volumetric moisture retention curve data with random errors for B C TM P sludge-soil mixtures.
pressure
[bar]
FC

0.1
0.3
0.5
0.7
1.0
2.0

PW P

5.0
10.0
15.0

moisture % vol.
original ± A WHCV blend ± A WHCV 40:10 ± A WHCV 30:20 ± A WHCV 25:25 + A WHCV 20:30 ± A WHCV 10:40 ± A WHCy

37

0.94
0.86
0.78
0.82
0.79
0.78
0.74
0.75
0.75

5;

0.80

46
42
38
40
39
38
38
37

44
45
43

1.11
0.96
0.91
0.89
0.89
0.92
0.89
0.92
0.88

4

0.93

55
47
45
44
44
45

48
46
44

48

1.18
1.10
0.96
0.99
0.99
0.92
1.05
1.04
0.98

6

1.02

58
54
47
49
49
45
51
51

64
47

43

0.99
0.93
0.90
0.94
0.90
0.88
0.91
0.91
0.88

35
37

1.31
0.97
0.73
0.73
0.75
0.74
0.72
0.71
0.74

3

0.92

10

0.82

46
45
43
45
45

36
36
37
36
35

36

0.81
0.88
0.69
0.69
0.71
0.71
0.77
0.80
0.74

43
43
42
41
41

1.10
0.99
0.90
0.84
0.87
0.88
0.85
0.83
0.85

7

0.75

8

0.90

40
43
34
34
35
35
38
39

54
49
44
41

FC = Field Capacity; PW P = Permanent Wilting Point; A W = Available W ater

64

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Moisture-retention-curves for Kraft mill sludge-soil-mixtures

Table 16: Volumetric moisture retention curve data with random errors for Kraft mill sludge-soil mixtures.
pressure
[bar]
FC

PW P

moisture % vol.
original ± A WHCV blend ± A WHCV 40:10

0.1

50

0.3
0.5
0.7
1.0
2.0

39
36
38
33
32

5.0
10.0

36
34

15.0

32

1.02
0.80
0.73
0.77
0.68
0.66
0.73
0.70
0.66

7

0.75

38

1.28
0.94
0.86
1.02
0.90
0.78
0.80
0.92
0.78

I 11

0.92

63
46
42
50
44
38
39
45

± A WHCV 30:20 ± A WHCV 25:25 ± A WHCV 20:30 ± A WHCv 10:40 ± A WHCv

34

1.17
0.89
0.80
0.89
0.81
0.73
0.81
0.69
0.69

9

0.83

57
43
39
44
40
36
40
34

37

1.38
0.98
0.89
1.01
0.88
0.77
0.75
0.71
0.76

h i I

0.90

68
48
44
49
43
38
37
35

36

1.26
0.95
0.92
0.75
0.83
0.74
0.77
0.75
0.74

11

0.86

62
47
45
37
41
36
38
37

33
35
31

1.13
0.90
0.82
0.73
0.80
0.65
0.67
0.71
0.63

13

0.78

55
44
40
36
39
32

57
47
40
39
38
36
34
33
36

11

1.16
0.97
0.81
0.97
0.78
0.73
0.70
0.67
0.73
0.81

FC = Field Capacity; PW P = Perm anent Wilting Point; A W = Available W ater

65

Bulk density decrease with addition of organic matter was reported in other
studies (Chow et al., 2003; Foley and Cooperband, 2002; Nemati, 2000). With
increasing organic matter, the bulk densities decreased and the porosity increased, thus
the water retention at field capacity was greater. At the wilting point, the water retained is
slightly lower, but exhibit similar trend. Foley and Cooperband (2002) reported a similar
relationship between bulk density and water retention in soil from field experiments. The
increase in water held at 0.3 bar is related to increased soil porosity, which allows the
soil to hold more water. However, the increase in small pores improved the soil’s ability
to retain water at 15 bar (Foley and Cooperband, 2002).
Plant available water slightly increased for BCTMP sludge-soil mixtures 25:25,
20:30, and 40:10 compared to the original sludge sample (Table 15). Plant available
water increased for all Kraft mill sludge-soil mixtures compared to the original sludge
sample (Table 16). Evidence of greater pore-size distribution and a shift toward smaller
pores is given by experimental findings from Bauer and Black (1992), suggesting that
greater moisture retention at field capacity might be offset by greater moisture retention
at the wilting point. These findings would support the plant available water results
determined in the laboratory.

Table 17: Volumetric moisture content in % and bulk density in g/cm3 of BCTM P
sludge-soil mixtures.
0.3 [bar]

= FC

15.0 [bar]

= PW P

BCTM P

moisture % vol.

Db [g/cm3]

moisture % vol.

D b [g/cm3]

original

42

0.16

37

0.15

blend

47

0.18

43

0.18

40:10

54

0.33

48

0.33

30:20

46

0.42

43

0.45

25:25

47

0.55

37

0.48

20:30

43

0.57

36

0.58

10:40

49

0.95

41

0.97

66

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Table 18: Volumetric moisture content in % and bulk density in g/cm3 of Kraft mill
sludge-soil mixtures.
0.3 [bar]

= FC

15.0 [bar]

= PW P

Kraft

moisture % vol.

D b [g/cm3]

moisture % vol.

D b [g/cm3]

original

39

0.13

32

0.14

blend

46

0.17

38

0.16

40:10

43

0.26

34

0.26

30:20

48

0.41

37

0.42

25:25

47

0.52

36

0.50

20:30

44

0.58

31

0.58

10:40

47

0.92

36

0.93

In this part of the experiment, the moisture content at 0.1 bar is an average of
two replicates, and 0.3 and 15 bar are averages of three replicates. The available water
is slightly higher for Kraft mill sludge and sludge-soil mixtures than for BCTMP sludge
and sludge-soil mixtures. For Kraft mill sludge plant available water is highest (13%) with
a sludge-soil mixture of 20:30. For BCTMP sludge it is highest (9%) with a 25:25 sludgesoil mixture.
The volumetric moisture content of the original sludge and soil samples
measured first (Table 14) are slightly higher for both sludge samples than when
measured with the sludge-soil mixtures (Table 15 and 16). BCTMP and Kraft mill sludge
are similar in their overall ability to hold water. Nevertheless, BCTMP sludge has higher
moisture content at field capacity for most sludge-soil mixtures except the mixtures
30:20 and 20:30. Volumetric moisture content decreases most over the entire pressure
range compared to Kraft mill sludge. Preparing the samples in the column is the most
crucial part of the experiment due to the different textures of the samples. This is
probably reflected in the different results of the two trials.

67

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The pressure plate experiment was also applied to sludge-soil layer systems.
The samples were prepared following the description in 3.2.11.1 (Figure 3). As the
overall height of the sample for the layer treatment was 6 cm instead of 1 cm used for
original samples and sludge-soil mixtures. As the time required to reach equilibrium
varies according to the square of the sample height, the layer systems never reached
equilibrium. Gravimetric moisture content was determined after 14 days for 0.5, 1.0, and
5.0 bar. Results for the moisture content are summarized in Table 19 for BCTMP sludgesoil layer systems and in Table 20 for Kraft mill sludge-soil layer systems. Data for bulk
density, moisture content, and error analysis are provided in appendix I (Table 82 to 85).
Layers of BCTMP sludge or layers of Kraft mill sludge have higher volumetric
moisture content than the soil layer. In the layer systems, the BCTMP sludge layer has
double the water holding capacity of soil. The Kraft mill sludge layer has a slightly higher
or same water holding capacity compared to the soil layer. In the layer systems BCTMP
sludge layer has more water holding capacity than Kraft mill sludge. Increasing the
amount of layers is not affecting the overall moisture content. For both sludge samples
volumetric moisture content remains similar throughout the sludge-soil layer systems.
The soil layer surrounded by sludge layers in the 2 and 3 layer systems has similar
moisture content as the first layer. This leads to the conclusion that water transmission
was induced by surrounding sludge and soil layers. There is less change in moisture
content of the soil layers than in the sludge layers.
As the equilibrium moisture content was not determined the data represent only a
trend. T h e volum etric m oisture c on ten t in the BCTMP slu dg e-so il la y e r s y s te m s is h ig h er

in the sludge layers at -0.5 bar compared to various sludge-soil mixtures and the original
sludge samples. It is higher in the BCTMP sludge-soil layer systems than in the Kraft mill
sludge-soil layer systems.

68

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Table 19: Total volumetric moisture content of 1, 2, and 3 BCTM P sludge-soil layer systems
at 0.5, 1.0, and 5.0 bar pressure.

pressure

0.5
WHCV

bar
total WHCV

[%]
48

[%]

sludge
soil

30

39.2

BCTM P

sludge 1
sludge 2

51
47

48
46

2 layers

soil 1

25

24

BCTM P
1 layer

BCTM P
3 layers

1.0 bar
WHCV total WHCV
[%]
51
24

[%]
37.5

5.0 bar
WHCV total WHCV
[%]
46

[%]

29

37.2

46
51
24

soil 2

33

sludge 1

42

53

sludge 2

39

43

36

sludge 3
soil 1
soil 2
soil 3

38
30
36

40
29
33

40
26

32

38.9

36.2

24

25

35.5

29

37.4

40

37.3

33
28

34.0

Table 20: Total volumetric moisture content of 1, 2, and 3 Kraft mill sludge-soil layer systems
at 0.5, 1.0, and 5.0 bar pressure.

pressure

Kraft mill

1 layer
Kraft mill

2 layers

Kraft mill
3 layers

0.5 bar
WHCV total WHCV
[%]
35

[%]

sludge
soil

28

31.8

sludge 1

38
34

1.0
WHCv

bar
total WHCV

5.0
WHCv

bar
total WHCV

[%]
27

[%]

[%]

30

28.4

[%]
26
28

35
31
23

sludge 2
soil 1
soil 2

21

sludge 1
sludge 2
sludge 3

35
36
25

33

28

38
29

28
24

soil 1
soil 2
soil 3

27
27
30

26
31
27

25
24

28

30.3

30.1

29

26.7

31
26
24
29.4

30.6

29

26

26.8

26.0

Water holding capacity determined by two different methods (i.e., soak and drain
method and pressure plate experiment) show the same trends for all 3 sludge-soil
treatments. The plain sludge samples have properties such as much lower bulk density
and higher porosity than the soil sample. This results in higher water holding capacity in

69

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the sludge samples. For the sludge-soil mixtures either method showed, that with
increasing organic matter, bulk density decreased and moisture retention increased. The
experimental set-up of the pressure plate equipment has its limitations in the sample
height. To analyze sludge-soil layer systems using the soak and drain method allows
keeping the sample height the same throughout the entire experiment. Water holding
capacity results can be compared. The pressure plate experiment is difficult and requires
runs of more than one week duration with samples greater than 1 cm in height. The soak
and drain method is less time consuming and replicates can be added more easily. More
specific information, such as percent of plant available water, can be determined with the
pressure plate experiment. The most crucial part of the experiment is the packing of the
columns. Soil and sludge are very different in structure. Soil being composed of smaller
and more uniform particles than sludge can be packed in the column evenly. Sludge
being composed of different types of fibers is more difficult to pack without defined
compaction. This is reflected in the error analysis for bulk density determination.
The topsoil or vegetative layer is part of a landfill capping system. The main
purpose of this system is to prevent infiltration and build the basis for environmental
restoration of the landfill area. The vegetative layer is exposed to heavy rainfalls,
desiccation, and freeze/thaw cycles. These events can cause severe damage to the
cover. The top layer is most vulnerable during germination and seedling growth time.
Sludge amended to soil could improve the performance of the topsoil layer. The
experimental findings show, that organic matter decreases bulk density and increases
porosity. The sludge amendment changes the soil structure by increasing the amount of
macropores, resulting in higher water retention capacity (Foley and Cooperband, 2002).
The changes in pore-size distribution increase the soil stability and resistance to
environmental impacts, especially heavy rainfalls (Nemati, 2000). Erosion and soil loss
problems caused by heavy rainfalls and stormwater runoff could be reduced as the

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sludge amended soil increases the water storage. Under simulated rainfall the beneficial
effects of a 4% organic matter treatment with a gravelly loam soil include 2.1 times delay
in runoff initiation, and 23 and 71% reduction in runoff and soil loss (Chow et al., 2003).
The most concentrated location of erosive forces on landfills occurs in the structures that
convey water from the top of the cap to the base of the side slopes (Cabalka, 1996).
Desiccation cracking and deterioration due to freeze/thaw cycles could also be
minimized by the change in the aggregation of the soil. Sludge could replace the
hydraulic mulch typically applied that offers a short-term (four- to eight-week) service life
to assist germination and seedling growth. Despite the advantages of the physical
properties of sludge amended soils, other amendments like compost, biosolids, or
manure need to be considered to provide nitrogen.
Ecological and economical evaluation of sludge amendment depends on regional
conditions. Costs for implementing the topsoil layer in general includes topsoil mixing
and

placing,

hydroseeding,

and

erosion

control

matting

are

approximately

CAD 10.00/m2. One quarter of this price is spent on erosion control matting. The Prince
George Regional District Landfill has a surface cover area of 49,886 m2. The top layer
has a minimum thickness of 60 cm. The construction, maintenance and after closure
costs of a landfill can be minimized, by using adequate alternative materials, which are
locally available.
Reduction of the deposition of organic wastes is one of the main goals of a
municipal solid waste landfill. Organic wastes account for most of the landfill gas and
le a c h a te pro b lem s as w ell a s s ettlem e n t pro b lem s. A fte r the clo su re o f a landfill, the

settlement problems affect the cover system including the top layer. Beyond financial
concerns, the reuse of sludge would reduce the input of organic matter to the landfill,
and save ever-shrinking landfill space. Sludge requires only basic equipment like a
manure spreader and bulldozer for placement. The high moisture content is ideal for

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placing and spreading. Cap construction with sludge can proceed under a broader range
of weather conditions. Sludge amended soils readily absorb large quantities of rainfall
reducing infiltration to the protective layer and storing water for vegetation growth during
dry periods.
All field studies were long-term experiments persisting between 1 and 7 years.
Even though more parameters like depth of water penetration and percolation time can
be determined in field experiments, the laboratory results of the moisture retention
determination are a concise alternative to predict amending effects in soil. A number of
functional forms were considered to describe the relationship between water content and
matric potential. None of the current functions adequately describe the data. An
acceptable function should provide minimum order of polynomial with a maximum
accuracy.

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Chapter 5

Summary

The objective of this study was to chemically and physically characterize sludge
from two different pulping processes to investigate their suitability as a substitute or
amendment in the topsoil layer of a landfill capping system. The purposes of the topsoil
layer are to enhance plant vegetation, moisture retention, and minimize infiltration and
chances of cracks followed by erosion and associated with infiltration problems.
Pulp mill sludge represents the waste portion of the pulping process. As the
wood input, the wood processing and the subsequent effluent treatment varies greatly,
so does the composition of the sludge. To identify potential environmental impacts,
elemental analysis was performed and the results compared to literature data from a mill
survey (NACSI, 2000) and typical nutrient concentrations sufficient for plant growth
(Barak, 1999). The BCTMP and Kraft mill sludge samples analyzed are low in potential
environmental contaminants. These results support previous findings.
Both sludge samples have high C:N ratios. The low nitrogen content often limits
the effectiveness of sludge as soil amendment. The N limitation could be alleviated with
appropriate fertilization and application rates. The type of sludge under consideration will
determine the fertilizer composition to enhance plant growth.
As the pH controls more or less nutrient availability, the neutral pH of BCTMP
sludge and alkaline pH of Kraft mill sludge could cause a deficiency for micronutrients,
eg. Fe, Zn that are important for plant growth. The pH could be altered by mixing sludge
with other material or determining appropriate loading rates. Mixtures of compost, or
biosolids, or boiler ash with sludge have been used successfully as forestry soil
amendment (NACSI, 2000).

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Sludge is composed mainly of organic matter. Various studies found that organic
amendments increase soil aggregation and stability, reduce bulk density, and increase
water holding capacity. This contribution of organic matter was investigated.
Soil has the highest bulk density, followed by BCTMP and Kraft mill sludge. The
original sludge samples have a higher bulk density than the blended samples. Blending
the sludge affects the fibre structure, resulting in lower bulk density.
Water holding capacity was determined by gravity and moisture retention curves
were established for original sludge and soil samples, various sludge-soil mixtures and
sludge-soil layer systems. In both experiments the blended sludge samples had the
highest water holding capacity and soil had the lowest. The sludge-soil mixtures
demonstrated increasing water holding capacity with increasing amounts of sludge
added to soil. The water holding capacity in the sludge-soil layer systems is lower in the
sludge layers than in the sludge-soil mixtures and the original sludge samples.
The moisture retention curves of BCTMP and Kraft mill sludge are similar in their
overall ability to hold water. BCTMP sludge, however, has higher moisture content at
field capacity and its moisture content decreases most over the entire pressure range
compared to Kraft mill sludge. The BCTMP sludge has the most plant available water.
The pressure plate experiment could not be applied successfully to the sludge-soil layer
system as with increasing sample height, the time to reach equilibrium increases
exponentially.
Laboratory experiments are a short-time, concise alternative to field studies and
the results can assist predicting the effect of sludge amendment to soil. The laboratory
findings should be validated by field studies to determine their application to real world
conditions. Kraft mill sludge and soil have similar water holding capacities. Compared to
Kraft mill sludge BCTMP sludge has a higher water holding capacity, resulting in high
water retention and higher amount of plant available water. Increasing organic matter

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amendment reduces soil bulk density and increases soil microbial activity, which
increases soil porosity. This alteration in soil physical properties is a consequence of the
pore size distribution of sludge and soil particles. These attributes of the sludge are
improving the performance of the topsoil layer with less environmental impact than the
current disposal options. Sludge could provide coverage for landfill cap erosion control
and vegetation needs. Another advantage for construction is the nature of the sludge, no
further treatment or special equipment is needed. Such use would reduce expenses on
mill and landfill budgets while conserving significant amount of valuable landfill space.
The results and conclusions from this study are not necessarily applicable to any
sludge in the pulp and paper industry. Based on this work it is recommended that any
end user contemplating using sludge in a landfill capping system should consider
chemical and physical characteristics of the sludge under consideration. The most
important parameter is the economic feasibility.

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Chapter 6

Recommendations for future work

Sludge amendments have the potential to protect the soil during critical periods of
vegetation establishment, thus reducing on-site damages and costs as well as reducing
off-site impacts on water quality.
1. Samples should be collected over a longer period of time, and mixed to have a
more representative sample for the experiments of interest.
2. Organic matter plays a fundamental role in the stabilization of soil structure and
the formation of pores. Other physical properties of interest to further realize the
potential of sludge as soil amendment are the effects of freezing and thawing
cycles and shear strength of the samples.
3. Field experiments should be implemented to confirm laboratory results on water
holding capacity (WHC) including important parameters like time and depth of
water infiltration after a wetting event.
4. Different treatments of sludge

(mixtures and

layer systems) should

be

investigated in field studies to determine the most effective application of sludge.
Future studies should include various sludge application rates, as well as other
amendments to increase plant available N. The process in a pulp mill can change
daily to effect the properties of sludge produced. The type of sludge determines
the fertilizer composition.
5.

Investigations on sludge decomposition and changes in C:N ratios over time
should be conducted to assess consequences of sludge amendments.

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6. Mathematical retention functions could be applied to express the relationship of
moisture content and matric potential and predict retention characteristics of
sludge.
7. The time to reach equilibrium is a crucial factor for the sludge-soil layer systems.
Future laboratory experiments should investigate whether different physical set
ups for the samples could reduce the time for equilibrium. Factors such as using
plastic columns with smaller diameter and compacting the sample under defined
conditions could be explored.
8. To get a better understanding of the pore-size distribution in sludge-soil mixtures,
samples of the mixtures should be observed under different magnifications under
the scanning electron microscope (SEM). Aggregation size could be determined
and compared to original sludge and soil samples.
9. The success of plant growth in the topsoil layer depends on various factors such
as soil quality, climate, and plant species. Research on various plant species
should be conducted to determine adequate species for successful long-term
revegetation.

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84

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Webb, L. 2000. Cleaning up after the papermakers. Pulp & Paper International, Aug.
2000, Vol. 42, Iss. 8, p. 24-27.
Wei, Q.F.; Lowery, B.; Peterson, A.E. 1985. Effect of sludge application on physical
properties of a silty clay loam. J. Environ, Qual. 14, p. 178-180.
Whitehead, D.C. 2000. Nutrient elements in grassland. Soil-plant-animal relationship.
CABI Publishing, Oxon, UK, 369 pp.
Zakis, G.F. 1994. Functional Analysis of Lignins and their Derivatives. Tappi Press,
Georgia, USA. 1994.
Zibilske, L.M.; Clapham, W.M.; Rourke, R.V. 2000. Multiple applications of paper mill
sludge in an agricultural system: Soil effects. J. Environ. Qual. 29: 1975-1981.

85

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Appendix A: Glossary
BCTMP: bleached chemi-thermomechanical pulping uses physical forces with some
additional heat and/or chemicals to separate wood fibers.

Capping system : a combination of several layers of diverse material for the final
closure of a landfill.

Dioxins: any of a group of chemical compounds that is an undesirable by-product in the
manufacture of herbicides, disinfectants, and other agents. In popular terminology,
dioxin has become a synonym for one specific dioxin 2,3,7,8-tetrachlorodibenzo-pdioxin (2,3,7,8-TCDD) from Encyclopaedia Britannica.

EPA: United States Environmental Protection Agency, responsible for protecting human
health and safeguarding the natural environment.

ICP-AES: Inductively coupled plasma-atomic emission spectroscopy is a quantitative
analytical technique for the determination of trace elements in samples.

Kraft pulping: chemical pulping process, also known as alkaline or sulphate process. It
is the most common method used in the pulp and paper industry.

MoELP: Ministry of Environment, Lands and Parks committed to protecting and
enhancing the quality of British Columbia’s environment; now Ministry of Water,
Land and Air Pollution and Ministry of Sustainable Resource Management.

NCASI: National Council for Air and Stream Improvement; Research Triangle Park in
North Carolina serving the forest industry

Original sludge: sludge sample as received from the mill without any treatment.

SEM: scanning electron microscope

86

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Appendix A: Glossary

Sludge: wastewater treatment plant solid residuals are those solid materials collected in
the process of treating water used in the mill prior to release into the environment.
Typically, these materials consist of solids collected in primary treatment
(separation of solids from raw wastewater) and secondary treatment (biological
treatment followed by clarification to separate biosolids). Often these primary and
secondary residuals are combined to facilitate handling (NCASI, 1999).

TAPPI: Technical Association of the Pulp and Paper Industry
Turpenes: By-product from the Kraft pulping process; a mixture of turpenes consists of
monoterpenes and pinenes. The basic structural unit is isoprene (C5H8).
UNBC: University of Northern British Columbia
WHC: Water holding capacity or water retention or field capacity or soil wetness
characteristics are all expressions for the soils ability to store water.

87

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Appendix B: Determination of moisture content in sludge samples
TABLE 21: Kraft mill sludge dried at 55 °C (n=8); uncertainty ± 0,0001
#

1
2
3
4
5

6
7

8

w A,

W

Wt

Ww

e

wd

Al dish [g] + sludge wet [g] + sludge dry [g] sludge wet [g] sludge dry [g]
3.1473
9.7137
5.7337
6.5664
2.5864
3.1389
9.9190
6.7801
2.6013
5.7402
3.1339
10.1768
5.7500
7.0429
2.6161
3.1354
9.8010
5.6838
6.6656
2.5484
3.1462
5.7202
6.7610
2.5740
9.9072
3.1463
10.1450
5.7366
6.9987
2.5903
3.1646
10.0738
6.0092
6.9092
2.8446
3.1458
10.0532
5.7814
6.9074
2.6356

moisture content [%]
154
161
169
162
163
170
143
162

160
8.72
+ 3.08

average
stdev
se

TABLE 22: Kraft mill sludge dried at 80 °C (n=8); uncertainty ± 0.0001
#

1
2
3
4
5

6
7

8

w A,

W

W t

W
¥VW

3.1541
3.1466
3.1377
3.1554

11.1413
10.5190
10.5869
11.1696

5.9925
5.7488
5.8402
5.9508

7.9872
7.3724
7.4492
8.0142

e

wd

Al dish [g] + sludge wet [g] + sludge dry [g] sludge wet [g] sludge dry [g]
10.6888
5.8524
7.5656
3.1232
2.7292
10.6486
2.6744
3.1358
5.8102
7.5128
3.1456
10.3413
5.5443
7.1957
2.3987
5.9415
3.1397
11.0038
7.8641
2.8018

moisture content [%]
177
181

200
181

2.8384
2.6022
2.7025
2.7954

181
183
176
187

183
7.58
±2 .68

average
stdev
se

TABLE 23: Kraft mill sludge dried at 105 °C (n=8); uncertainty ± 0.0001
#

1
2
3
4
5

6
7

8

w A1

W

W t

W
* ¥w

wd

Al dish [g] + sludge wet [g] + sludge dry [g] sludge wet [g] sludge dry [g]
3.1200
9.9696
5.8332
6.8496
2.7132
3.1300
5.7059
6.4682
2.5759
9.5982
3.1405
10.0065
5.7522
6.8660
2.6117
10.0875
5.6582
2.5228
3.1354
6.9521
3.1497
10.2195
5.7845
7.0698
2.6348
3.1423
10.1312
5.7506
6.9889
2.6083
5.8949
7.6595
2.7632
3.1317
10.7912
3.1524
5.7439
2.5915
9.9102
6.7578

e
moisture content [%]
152
151
163
176
168
168
177
161

average
stdev
se

165
9.65
±3.41

88

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix B: Determination of moisture content in sludge samples
TABLE 24: BCTM P sludge dried at 55 °C (n=8); uncertainty ± 0.0001
#

1
2
3
4
5

6
7

8

wA,

W

wt

W

* * W

3.1738
3.1574
3.1677
3.1583
3.1492
3.1516
3.1429

10.1558
10.1315
10.1080
10.4646
10.4175
10.0293
10.0700

5.9669
5.9270
5.8984
6.0204
5.9833
5.8311
5.8303

6.9820
6.9741
6.9403
7.3063
7.2683
6.8777
6.9271

0

wd

Al dish [g] + sludge wet [g] + sludge dry [g] sludge wet [g] sludge dry [g]
3.1356
10.0053
5.8749
6.8697
2.7393

moisture content [%]
151

2.7931
2.7696
2.7307
2.8621
2.8341
2.6795
2.6874

150
152
154
155
156
157
158

average
stdev
se

154
2.93
± 1.04

TABLE 25: BCTM P sludge dried at 80 °C (n=6); W * =porcelain dish; uncertainty ± 0.0001
#

1
2
3
4
5

6

W*
dish [g]
55.5007
55.0895
56.2052
54.9497
55.9984
57.1587

W

Wt

Ww

e

wd

+ sludge wet [g] + sludge dry [g] sludge wet [g] sludge dry [g]
56.9204
5.3120
1.4197
60.8127
56.4515
5.1978
1.3620
60.2873
1.3781
61.4097
57.5833
5.2045
1.3661
60.1029
56.3158
5.1532
61.2109
57.3514
5.2125
1.3530
62.1692
58.4543
5.0105
1.2956

moisture content [%]
274
282
278
277
285
287

280
4.93
± 2.01

average
stdev
se
TABLE 26: BCTM P sludge dried at 105 °C (n=8); uncertainty ± 0.0001
#

1
2
3
4
5

6
7

8

wA,

W

wt

ww

wd

Al dish [g] + sludge wet [g] + sludge dry [g] sludge wet [g] sludge dry [g]
5.6825
2 .5480
3.1345
9.8600
6.7255
2.8391
3.1721
10.8150
6.0112
7.6429
2.6408
3.1554
9.9368
5.7962
6.7814
2.6843
3.1645
10.0964
5.8488
6.9319
2.6846
3.1565
10.3138
7.1573
5.8411
5.7983
6.9383
2.6514
3.1469
10.0852
6.0881
2.9385
3.1496
10.9675
7.8179
2.5449
3.1408
10.0391
5.6857
6.8983

e
moisture content [%]
164
169
157
158
167
162

average
stdev
se

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

166
171

164
5.04
± 1.78

Appendix C: Determination of total C and total N

T A B L E 27: T o ta l c a rb o n a n d n itro g e n ra w d a ta ( n = 4 )

sample
'C
CM

-4— '

Kraft mill sludge (1)
Kraft mill sludge (2)
Kraft mill sludge (1)
Kraft mill sludge (2)

total N % total C %

0.00
0.00
0.14
0.12

44.01
44.56
39.66
43.65

sample
•f—>

CM

■+—>

BCTMP sludge (1)
BCTMP sludge (2)
BCTMP sludge (1)
BCTMP sludge (2)

total N % total C %

1.18
1.16
1.47
1.32

53.59
53.73
50.06
51.62

a v e ra g e

0.07

4 2.97

a v e ra g e

1.28

52.25

s td e v

0.08

2.24

s td e v

0.14

1.75

± se

0.04

1.12

± se

0.07

0.87

90

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Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix D: Determination of ash content in sludge and soil samples

TABLE 28: Ash content of sludge and soil samples
(BCTM P and Kraft mill ash samples were weighed with lid. Soil ash samples were weighed without lid.)

n=3
sample
crucible + lid [g]
crucible [g]
crucible+sample[g]
sample wet [g]
dried at 105° C
sample dry [g]
ash after 4h [g]
ash after 6h [g]
ash after 8h [g]
ash [g]
ash content %
average %
stdev
se

B C TM P (1)
85.1951
5 4.9472
56.5230
1.5758
55.3414
0.3942
85.2124
85.2109
85.2123
0.0172
4.36

B C TM P (2)
87.3807
55.9816
57.5132
1.5316
56.3607
0.3791
87.3989
87.3969
87.3984
0.0177
4.67

n -3

B C TM P (3) Kraft mill (1) Kraft mill (2) Kraft mill (3)
85.8533
85.8868
90.6643
85.9560
56.1963
55.4978
55.0871
57.1441
57.5989
56.6113
56.5255
5 8.6368
1.4026
1.1135
1.4384
1.4927
56.5761
55.7878
55.4718
57.5114
0.3798
0.2900
0.3847
0.3673
85.9068
85.9670
85.8703
90.6799
85.9036
85.8682
90.6781
85.9657
85.9678
85.8698
85.9052
90.6796
0.0118
0.0165
0.0184
0.0153
4.29
4.84
4.17
4.07
4 .40
0.254
± 0 .146

4.40
0.400
± 0.231

n=3
soil (1)
85.9571
55.4977
56.8018
1.3041
56.6137
1.1160
56.5917
56.5932
56.5915
1.0938
98.01

soil (2)
85.8522
55.0868
56.5075
1.4207
56.3030
1.2162
5 6.2796
56.2812
56.1850
1.0982
90.30

soil (3)
85.8868
56.1967
57.5212
1.3245
57.3372
1.1405
57.3151
57.3170
57.3153
1.1186
98.08
95.5
4 .4 7
± 2 .5 8

91

Appendix E: Energy Dispersive X-ray Analysis

TABLE 29: Elemental analysis of Kraft mill sludge; elements are expressed in relative percentage.
A:\Kraft Mill.SPC
Acquisition Tim e : 08:54:34

Date : 15-Mar- 2

kV:20.00

Tilt: 0.00

Take-off:20.0C Tc:40

Detector Type :SU TW

Resolution :151.58

Lsec :183

EDAX ZAF Quantification
Element Normalized

Standardless

Element

Wt %

At %

K-Ratio

Z

A

F

C K
0 K
NaK
SiK
S K
K K

68.89
26.27
3.69
0.77

75.72

1.008

21.68
2.12

0.3817
0.0395

0.36

0.0056

1.0002
1.0001
1.0001
1.0001

0
0

0
0

0
0

CaK
Total

0.38

0.13

0.0037

0.9912
0.928
0.9508
0.9292
0.8981
0.9198

0.5495
0.1518
0.3499

100

100

Element

Net Inte.

Bkgd Inte.

Inte. Error

P/B

C K
0 K
NaK
SiK
S K
K K
CaK

7.87

0.64

2.74

12.24

1.28
0.93
0.5

1.99
3.6
2.45

10.43
16.86
25.56

0.64
0.26

0
0
0.22

2.1
1.57
1.3

0
0

0.2
0
0

41.76

0.17

0.012

0.7714
0.9486
1.0462
1.0541

K-Ratio - constant
Z, A, F - correction factors: Z= atomic number
A= absorption factor
F= fluorescence

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

1.0003
1.0014

1

Appendix E: Energy Dispersive X-ray Analysis

TABLE 30: Elemental analysis of BCTM P sludge; elemen+s are expressed in relative percentage.
A:\BCTMP.spc
Acquisition Time : 09:09:03

Date : 15-M ar- 2

kV:20.00
Detector Type :SUTW

Tilt: 0.00
Resolution :151.58

EDAX ZAF Quantification
Element Normalized

Standardless

Take-off:20.00 Tc:40
Lsec :37

Element

W t%

At %

K-Ratio

Z

A

F

C K
0 K
NaK
SiK
S K
KK
CaK
Total

58.2
38.02
1.42
0.33
0.25
0.55
1.23

65.95
32.34
0.84
0.16

0.3105
0.064
0.0041
0.0023

0.0022

0.19
0.42

0.0052
0.0118

0.5284
0.1696
0.3112
0.7503
0.942
1.0419
1.046

1.0003

0.11

1.0092
0.9925
0.9292
0.952
0.9307
0.8994
0.9212

100

1G8

Element

Net Inte.

Bkgd Inte.

Inte. Error

P/B

C K
0 K
NaK
SiK

108.15
35.01
5.38
3.48
2.69
5.54
11.69

2.32
8.39
14.59
20.13
14.8
10.05
9.82

1.58
3.06
13.49

46.58
4.17
0.37
0.17
0.18
0.55
1.19

S K
KK
CaK
K-Ratio - constant
Z, A, F - correction factors:

22.66
25.24
11.58
6.44

Z= atomic number
A= absorption factor
F= fluorescence

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

1
1.0001
1.0005

1.0012
1.0042

1

Appendix F: Cation exchange capacity

TABLE 31:

Effective cation exchange capacity and exchangable Al, Fe, K, Mg, Mn, and Na for BCTM P
and Kraft mill sludge and soil samples.
(Analysis was conducted by British Columbia Ministry of Forests Research Laboratory,
Analytical Chemistry Section)

Sample

soil 1
soil 2
soil 3

Exch Al
cmol+/kg

Exch Ca
cmol+/kg

Exch Fe Exch K Exch Mg Exch Mn Exch Na CEC (Ba)
cmol+/kg cmol+/kg cmol+/kg cmol+/kg cmol+/kg cmol+/kg
5.231
5.142
5.318

0.04
0.04
0.04

0.196
0.195

0.001

0.300
0.294
0.302

0.212

Effective
15.24
15.01
15.51

0.001
0.001
± 0.0003

0.299
0.004
± 0.0013

5.230
0.088
± 0.0293

0.040
0.001
± 0.0003

0.201
0.010
± 0.0033

15.25
0.250
± 0.0833

26.793
27.082
26.585

0.006

0.755
0.761
0.743

3.456

35.23

3.492
3.422

0.06
0.06
0.06

4.124

0.006
0.005

4.163
4.058

35.60
34.91

0.037
0.001

26.820
0.250

0.006
0.001

0.753
0.009

3.457
0.035

0.061
0.001

4.115
0.053

35.25
0.345

± 0.0003

± 0.0833

± 0.0003

± 0.0030

± 0 .0 1 1 7

± 0.0003

± 0 .0 1 7 7

± 0 .1 1 5 0

< 0.001
< 0.001
< 0.001

13.015
13.174
12.996

< 0.001
< 0.001
< 0.001

0.474
0.474
0.435

5.428
5.413
5.385

0.07
0.07
0.07

0.686
0.721
0.729

19.66
19.84
19.61

< 0.001
< 0.001
± 0.0003

13.062
0.098
± 0.0327

< 0.001

0.461
0.023
± 0.0077

5.409
0.022
± 0.0073

0.070
0.001
± 0.0003

0.712
0.023
± 0.0077

19.70
0.121
± 0.0403

0.002
0.009
0.009

9.474
9.328
9.629

< 0.001
0.003

0.007
0.004
± 0.0013

9.477
0.151
± 0.0503

BCTMP 1
BCTMP 2
BCTMP 3

0.036
0.037
0.037

average
stdev
se

Kraft mill 1
Kraft mill 2
Kraft mill 3

average
stdev
se

average
stdev
se

< 0.001
± 0.0003

94

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix G: Elememtal analysis

TABLE 32:

Elemental analysis of oven-dried BCTM P and Kraft mill sludge by ICP-AES.
(Aluminium, Boron, Calcium, Cadmium, Cobalt, Chromium, Copper, Iron,
Potassium, Magnesium, Manganese, Molybdenium, Sodium, Nickel, Phosphorus,
Lead, Zinc).

1BDL = below detection limit

n-4
Element
Aluminum
Boron
Calcium
Cadmium
Cobalt
Chromium
Copper
Iron
Potassium
Magnesium
Manganese

Detection Limit Kraft mill
[ppm]
[pg/g]

stdev

n=4
± se

BCTMP

stdev

± se

[pg/g]

0.068
0.01
0.009
0.008
0.05
0.025
0.006
0.007
0.5
0.003
0.001

702
0.672
5931
0.088
0.582
4.97
14.51
587
72.8
1795
89.0

46.4
0.604
238
0.106
0.416
1.63
3.58
35.0
54.6
36.4
9.99

23.2
0.302
119
0.053
0.208
0.816
1.79
17.5
27.3
18.2
4.99

295
62.0
7936
0.232
1.491
13.52
7.87
312
277
478
28.6

23.7
1.28
86.6
0.241
4.59
1.80
37.4
56.4
21.4
1.06

11.9
0.642
43.3
0.121
0.585
2.30
0.90
18.7
28.3
10.7
0.529

0.062

-

-

-

-

30.7
1.488
54.4

15.36
0.752
27.2

1BDL
904
8.088
932

24.9
6.961
61.4

2.75
10.1

1.38
5.08

1BDL
28.4

49.8
13.75
123
1.84

0.910

Molybdenium
Sodium
Nickel
Phosphorus

0.05
0.019
0.35

1BDL
162
1.819
41.2

Lead
Zinc

0.125
0.012

4.09
30.5

1.171

-

95

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix H: Determination of gravimetric w ater holding capacity
P a rt A : Bulk density

TABLE 33: Raw data for sludge and soil samples; (n=5)

sample
Kraft mill sludge 1
Kraft mill sludge 2
Kraft mill sludge 3
Kraft mill sludge 4
Kraft mill sludge 5
BCTMP sludge 1
BCTM P sludge 2
BCTM P sludge 3
BCTM P sludge 4
BCTM P sludge 5
Soil 1
Soil 2
Soil 3
Soil 4
Soil 5

column empty column&sludge mass wet

[g]

[g]

[g]

63.372
63.778
63.170
63.502
63.842
63.504
63.360
63.600
65.150
65.578
63.566
64.194
63.272
63.494
63.850

112.052
114.602
111.812
111.844
112.176
129.685
130.935
132.065
133.835
134.275
220.510

48.680
50.824
48.642
48.342
48.334
66.181
67.575
68.465
68.685
68.697
156.944

213.270
215.632
213.062
214.690

149.076
152.360
149.568
150.840

height
[cm]

volume
[cm3]

4.1
4.0
4.0
3.9
4.0
3.9
3.8
4.0
3.9
3.8
3.8
3.7
3.7
3.7
3.7

153.23
149.50
149.50
145.76
149.50
145.76
142.02
149.50
145.76
142.02
142.02
138.28
138.28
138.28
138.28

height
[cm]

volume
[cm3]

3.7
3.5
3.5
3.7
3.7
3.5
3.9
3.9
3.8
4.0

138.28
130.81
130.81
138.28
138.28
130.81
145.76
145.76
142.02
149.50
145.76
149.50
145.76
149.50
149.50
149.50
149.50
156.97

TABLE 34: Raw data for Kraft mill sludge-soil mixtures; (n=3)

sample
Kraft mill/so I 10:40; 1
Kraft mill/so I 10:40; 2
Kraft mill/so I 10:40; 3
Kraft mill/so I 20:30; 1
Kraft mill/so I 20:30; 2
Kraft mill/so I 20:30; 3
Kraft mill/so I 25:25: 1
Kraft mill/so I 25:25: 2
Kraft mill/so 125 :2 5:3
Kraft mill/so 130:20; 1
Kraft mill/so I 30:20; 2
Kraft mill/so I 30:20; 3
Kraft mill/so 140:10; 1
Kraft mill/so I 40:10; 2
Kraft mill/so 140:10; 3
Kraft mill orig. blend 1
Kraft mill orig. blend 2
Kraft mill orig. blend 3

column empty column&sludge mass wet

[g]

[g]

[g]

63.918
63.586
63.446
63.282
63.728
63.156
63.392
63.812
63.346
64.342
63.234
63.370
63.798
63.210
63.324
64.918
64.788
63.712

142.585
135.540
138.380
113.336
114.504
113.050
113.322
114.260
113.900
114.702
112.806
113.458
107.488
109.148
107.194
104.416
105.374
105.808

78.667
71.954
74.934
50.054
50.776
49.894
49.930
50.448
50.554
50.360
49.572
50.088
43.690
45.938
43.870
39.498
40.586
42.096

3.9
4.0
3.9
4.0
4.0
4.0
4.0
4.2

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix H: Determination of gravimetric water holding capacity

TABLE 35: Raw data for BCTM P sludge-soil mixtures; (n=3)

sample
BCTMP/so I 10:40; 1
BCTMP/so I 10:40; 2
BCTMP/so I 10:40; 3
BCTMP/so I 20:30; 1
BCTMP/so I 20:30; 2
BCTMP/so I 20:30; 3
BCTMP/so I 25:25; 1
BCTMP/so I 25:25; 2
BCTMP/so I 25:25; 3
BCTMP/so I 30:20; 1
BCTMP/so I 30:20; 2
BCTMP/so I 30:20; 3
BCTMP/so 140:10; 1
BCTMP/so 140:10; 2
BCTMP/so 140:10; 3
BCTM P orig. blend 1
BCTM P orig. blend 2
BCTM P orig. blend 3

column empty column&sludge mass wet

[g]

[g]

[g]

63.328
63.938
62.900
63.682
63.786
63.854
64.598
65.464
63.556
65.934
64.078
63.802
63.920
63.558
63.398
63.378
63.774

166.365
165.980
163.510
138.655
139.030
138.620
135.750
145.355
133.525
135.920
144.625
139.425
130.700
130.330
131.435
116.058
122.815
127.46

103.037
102.042
100.610
74.973
75.244
74.766
71.152
79.891
69.969
69.986
80.547
75.623
66.780
66.772

63.192

68.037
52.680
59.041
64.268

height
[cm]

volume
[cm3]

3.8
3.5
3.5
3.5
3.5
3.4
3.8
3.9
3.5
4.0
4.1
3.9
3.9
3.9
3.9
3.9
4.0
4.1

142.02
130.81
130.81
130.81
130.81
127.07
142.02
145.76
130.81
149.50
153.23
145.76
145.76
145.76
145.76
145.76
149.50
153.23

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix H: Determination of gravimetric moisture content
TABLE 36: Total dry sample mass and Db for sludge and soil samples
(Volume for Db calculation as determined in table 33)

sample
Kraft mill 1a
Kraft mill 1b
Kraft mill 2a
Kraft mill 2b
Kraft mill 3a
Kraft mill 3b
Kraft mill 4a
Kraft mill 4b
Kraft mill 5a
Kraft mill 5b
BCTM P 1a
BCTM P 1b
BCTM P 2a
BCTM P 2b
BCTM P 3a
BCTM P 3b
BCTM P 4a
BCTM P 4b
BCTM P 5a
BCTM P 5b
Soil 1a
Soil 1b
Soil 2a
Soil 2b
Soil 3a
Soil 3b
Soil 4a
Soil 4b
Soil 5a
Soil 5b

Db average stdev
sludge wet sum wet sludge dry sum dry total mass
[g/cm3]
dry [g]
(n=5)
[g]
[g]
[g]
[g]
12.231
15.277
15.977
18.522
15.840
19.057
19.384
17.033
20.634
20.293
10.204
9.250
9.501
10.073
12.813
11.749
12.570
12.004
13.339
12.026
28.893
25.484
25.206
27.750
26.399
25.082
31.167
28.342
24.417
25.018

27.508
34.499
34.897
36.417
40.927
19.454
19.574
24.562
24.574
25.365
54.377
52.956
51.481
59.509
49.435

2.122
2.490
2.666
3.087
2.610
3.189
2.999
2.873
3.280
3.207
2.096
1.929
2.046
2.152
2.618
2.390
2.533
2.412
2.525
2.271
21.630
19.219
19.302
21.493
19.876
18.782
23.398
21.023
18.660
19.324

4.612

8.162

0.053

5.753

8.475

0.057

5.799

8.083

0.054

5.872

7.795

0.053

6.487

7.661

0.051

4.025

13.69

0.094

4.198

14.49

0.102

5.008

13.96

0.093

4.945

13.82

0.095

4.796

12.99

0.091

40.849

117.90

0.830

40.795

114.84

0.830

38.658

114.41

0.827

44.421

111.65

0.807

37.984

115.90

0.838

± se

0.054

0.002

0.001

0.095

0.004

0.002

0.827

0.012

0.005

98

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix H: Determination of gravimetric moisture content
TABLE 37: Total sample mass dry and Db for Kraft mill sludge-soil mixtures
(Volume for Db calculation as determined in table 34)

sludge wet sum wet sludge dry sum dry total mass
Db average stdev
[g/cm3]
(n=3)
dry
[g]
[g]
[g]
[g]
[g]

sample
Kraft m ll/soil 10:40
Kraft m ll/soil 10:40
Kraft m ll/soil 10:40
Kraft m ll/soil 10:40
Kraft m ll/soil 10:40
Kraft m ll/soil 10:40
Kraft m ll/soil 20:30
Kraft m ll/soil 20:30
Kraft m ll/soil 20:30
Kraft m ll/soil 20:30
Kraft m ll/soil 20:30
Kraft m ll/soil 20:30
Kraft m ll/soil 25:25
Kraft m ll/soil 25:25
Kraft m ll/soil 25:25
Kraft m ll/soil 25:25
Kraft m ll/soil 25:25
Kraft m ll/soil 25:25
Kraft m ll/soil 30:20
Kraft m ll/soil 30:20
Kraft m ll/soil 30:20
Kraft m ll/soil 30:20
Kraft m ll/soil 30:20
Kraft m ll/soil 30:20
Kraft m ll/soil 40:10
Kraft m ll/soil 40:10
Kraft m ll/soil 40:10
Kraft m ll/soil 40:10
Kraft m ll/soil 40:10
Kraft m ll/soil 40:10

1a
1b
2a
2b
3a
3b
1a
1b
2a
2b
3a
3b
1a
1b
2a
2b
3a
3b
1a
1b
2a
2b
3a
3b
1a
1b
2a
2b
3a
3b

14.646
13.169
11.711
11.748
9.704
10.173
10.303
10.388
9.534
9.287
9.785
12.003
7.882
7.268
10.499
7.744
9.116
8.362
9.119
9.167
11.718
11.099
13.756
10.054
11.513
11.177
13.983
14.085
10.143
9.684

27.815
23.459
19.877
20.691
18.821
21.788
15.150
18.243
17.478
18.286
22.817
23.810
22.690
28.068
19.827

9.024
7.908
7.063
7.152
5.262
6.871
3.735
4 .099
3.900
3.684
4.986
5.643
3.319
2.518
4.972
2.856
3.970
3.561
2.763
2.715
4.067
2.795
3.853
2.523
2.395
1.901
2.427
2.374
2.031
1.778

16.932

47.89

0.346

14.215

43.60

0.333

12.133

45.74

0.350

7.834

18.95

0.137

7.584

20.46

0.148

10.629

24.34

0.186

5.837

19.24

0.132

7.828

21.65

0.149

7.531

21.78

0.153

5.478

15.09

0.101

6.862

14.91

0.102

6.376

13.41

0.090

4.296

8.27

0.057

4.801

7.86

0.053

3.809

8.43

0.056

± se

0.343

0.009

0.005

0.157

0.026

0.015

0.145

0.011

0.006

0.098

0.007

0.004

0.055

0.002

0.001

99

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix H: Determination of gravimetric moisture content

average stdev
Db
sludge wet sum wet sludge dry sum dry total mass
dry [g] [g/cm3] (n=3)
[g]
[g]
[g]
[g]

sample
Kraft mil orig.blend 1a
Kraft mill orig.blend 1 b
Kraft mill orig.blend 2a
Kraft mill orig.blend 2b
Kraft mill orig.blend 3a
Kraft mill orig.blend 3b

10.182
12.963
11.025
10.993
13.830
12.810

23.145
22.018

1.262
1.541
1.352
1.324
1.753
1.643

2.803

4.78

0.032

2.676

4.93

0.033

3.396

5.37

0.034

0.001

0.001

average stdev
Db
sludge wet sum wet sludge dry sum dry total mass
[g/cm3]
dry [g]
(n=3)
[g]
[g]
[g]
[g]

± se

26.640

0.033

± se

TABLE 38: Total sample mass dry and Db for BCTM P sludge-soil mixtures
(Volume for Db calculation as determined in table 35)

sample
BCTMP/soil 10:40
BCTMP/soil 10:40
BCTMP/soil 10:40
BCTMP/soil 10:40
BCTMP/soil 10:40
BCTMP/soil 10:40
BCTMP/soil 20:30
BCTMP/soil 20:30
BCTMP/soil 20:30
BCTMP/soil 20:30
BCTMP/soil 20:30
BCTMP/soil 20:30
BCTMP/soil 25:25
BCTMP/soil 25:25
BCTMP/soil 25:25
BCTMP/soil 25:25
BCTMP/soil 25:25
BCTMP/soil 25:25

1a
1b
2a
2b
3a
3b
1a
1b
2a
2b
3a
3b
1a
1b
2a
2b
3a
3b

9.947
10.240
11.705
11.871
11.513
10.754
12.047
11.693
10.084
9.368
12.696
11.169
10.508
8.815
10.658
9.835
9.845
7.904

20.187
23.576
22.267
23.740
19.452
23.865
19.323
20.493
17.749

6.779
6.658
7.620
7.675
7.636
7.082
6.165
5.788
5.512
4.743
7.640
6.191
5.015
4.010
5.212
4.719
5.120
3.762

13.437

68.58

0.483

15.295

66.20

0.506

14.718

66.50

0.508

11.953

37.75

0.289

10.255

39.67

0.303

13.831

43.33

0.341

9.025

33.23

0.234

9.931

38.72

0.266

8.882

35.01

0.268

0.499

0.014

0.008

0.311

0.027

0.016

0.256

0.019

0.011

100

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix H: Determination of gravimetric moisture content

sample
BCTMP/soil 30:20; 1a
BCTMP/soil 30:20; 1b
BCTMP/soil 30:20; 2a
BCTMP/soil 30:20; 2b
BCTMP/soil 30:20; 3a
BCTMP/soil 30:20; 3b
BCTMP/soil 40:10; 1a
BCTMP/soil 40:10; 1b
BCTMP/soil 40:10; 2a
BCTMP/soil 40:10; 2b
BCTMP/soil 40:10; 3a
BCTMP/soil 40:10; 3b
B C TM P orig. blend 1a
B C TM P orig. blend 1b
B C TM P orig. blend 2a
B C TM P orig. blend 2b
B C TM P orig. blend 3a
B C TM P orig. blend 3b

average stdev
sludge wet sum wet sludge dry sum dry total mass Db
[g/cm3]
dry
[g]
(n=3)
[g]
[g]
[g]
[g]
12.080
12.124
9.499
9.469
6.927
11.770
7.221
8.829
8.658
7.903
8.435
7.621
7.686
8.224
8.376
7.954
7.322
8.484

24.204
18.968
18.697
16.050
16.561
16.056
15.910
16.330
15.806

4.464
4.300
3.236
3.318
2.754
4.159
1.907
2.284
2.121
1.894
2.290
1.882
1.260
1.353
1.329
1.263
1.167
1.372

8.764

25.34

0.170

6.554

27.83

0.182

6.913

27.96

0.192

4.191

17.44

0.120

4.015

16.19

0.111

4.172

17.68

0.121

2.613

8.65

0.059

2.592

9.37

0.063

2.539

10.32

0.067

± se

0.181

0.011

0.006

0.117

0.005

0.003

0.063

0.004

0.002

101

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix H: Determination of gravimetric water holding capacity
TABLE 39: Raw data fo r K raft mill sludge-soil layer system s and Db; 1, 2, and 3 layer syste m s (n=3)

sample

<1)
>

G)
>s
_C0

<D

sludge (1/1)
soil (1/1)
sludge (2/1)
soil (2/1)
sludge (3/1)
soil (3/1)
sludge (1/1)
soil (1/1)
sludge (1/2)
soil (1/2)
sludge (2/1)
soil (2/1)
sludge (2/2)
soil (2/2)
sludge (3/1)
soil (3/1)
sludge (3/2)
soil (3/2)
sludge (1/1)
soil (1/1)
sludge (1/2)
soil (1/2)
sludge (1/3)
soil (1/3)
sludge (2/1)
soil (2/1)
sludge (2/2)
soil (2/2)
sludge (2/3)
soil (2/3)
sludge (3/1)
soil (3/1)
sludge (3/2)
soil (3/2)
sludge (3/3)
soil (3/3)

column empty

column&sample

mass wet

[g]

[g]

[g]

64.100
64.100
63.818
63.818
63.298
63.298
64.474
64.474
64.474
64.474
63.604
63.604
63.604
63.604
63.582
63.582
63.582
63.582
63.148
63.148
63.148
63.148
63.148
63.148
64.366
64.366
64.366
64.366
64.366
64.366
62.876
62.876
62.876
62.876
62.876
62.876

99.690
228.850
102.658
228.140
103.004
239.435
83.232
159.620
178.785
253.340
82.754
147.160
172.730
241.905
84.778
146.990
172.075
247.480
82.412
109.482
132.000
173.985
193.450
254.035
85.452
120.225
140.040
183.650
200.825
255.020
82.608
113.670
132.055
175.875
191.500
239.195

35.590
164.750
38.840
164.322
39.706
176.137
18.758
95.146
114.311
188.866
19.150
83.556
109.126
178.301
21.196
83.408
108.493
183.898
19.264
46.334
68.852
110.837
130.302
190.887
21.086
55.859
75.674
119.284
136.459
190.654
19.732
50.794
69.179
112.999
128.624
176.319

height volume mass dry
[cm]
[cm3]
[g]
3.0
112.12
35.590
8.31
129.160
2.7
100.91
93.72
112.12
38.840
3.0
12.51
2.7
100.91
89.24
125.482
3.1
115.86
39.706
7.51
136.431
2.8
104.65
97.75
56.06
18.758
1.5
3.31
1.6
59.80
56.03
76.388
52.32
19.165
1.4
3.43
1.4
52.32
74.555
53.83
19.150
1.4
52.32
3.38
64.406
1.6
59.80
46.31
1.4
52.32
4.13
25.570
69.175
1.6
59.80
49.60
21.196
1.5
56.06
3.40
62.212
1.5
56.06
45.31
25.085
1.5
56.06
4.16
75.405
1.5
56.06
54.13
19.264
1.3
48.59
3.40
27.070
0.8
29.90
19.68
1.0
37.37
22.518
5.18
37.37
41.985
1.0
30.86
19.465
1.0
37.37
3.72
37.37
60.585
1.0
44.07
1.1
41.11
21.086
3.61
37.37
34.773
1.0
25.67
37.37
19.815
1.0
3.87
1.1
43.610
41.11
31.38
33.64
17.175
0.9
3.28
37.37
54.195
1.0
38.91
19.732
1.2
44.85
3.24
33.64
31.062
0.9
23.07
37.37
18.385
1.0
3.74
43.820
1.0
37.37
31.48
33.64
15.625
0.9
2.98
47.695
1.1
41.11
34.46
layer

[g]

Db
[g/cm3]
0.0741
0.9287
0.1116
0.8844
0.0648
0.9341
0.0591
0.9371
0.0655
1.0289
0.0646
0.7745
0.0789
0.8295
0.0606
0.8082
0.0743
0.9656
0.0700
0.6582
0.1386
0.8256
0.0995
1.1793
0.0878
0.6868
0.1035
0.7632
0.0976
1.0410
0.0723
0.6859
0.1001
0.8423
0.0887
0.8382

102

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix H: Determination of gravimetric water holding capacity
TABLE 40: Raw data for BCTMP sludge-soil layer systems and Db; 1, 2, and 3 layer systems (n=3)

sample

a>

>

s—
CD

>.

TO
CM

d)

>.
03

00

sludge (1/1)
soil (1/1)
sludge (2/1)
soil (2/1)
sludge (3/1)
soil (3/1)
sludge (1/1)
soil (1/1)
sludge (1/2)
soil (1/2)
sludge (2/1)
soil (2/1)
sludge (2/2)
soil (2/2)
sludge (3/1)
soil (3/1)
sludge (3/2)
soil (3/2)
sludge (1/1)
soil (1/1)
sludge (1/2)
soil (1/2)
sludge (1/3)
soil (1/3)
sludge (2/1)
soil (2/1)
sludge (2/2)
soil (2/2)
sludge (2/3)
soil (2/3)
sludge (3/1)
soil (3/1)
sludge (3/2)
soil (3/2)
sludge (3/3)
soil (3/3)

column empty column&sampie mass wet

layer

[g]

[g]

[g]

[g]

64.114
64.114
63.998
63.998
63.140
63.140
63.192
63.192
63.192
63.192
63.870
63.870
63.870
63.870
63.122
63.122
63.122
63.122
63.138
63.138
63.138
63.138
63.138
63.138
63.752
63.752
63.752
63.752
63.752
63.752
63.150
63.150
63.150
63.150
63.150
63.150

117.084
242.620
115.350
250.960
112.048
255.955
92.962
147.850
189.470
242.250
93.750
147.685
189.360
252.450
94.596
147.395
182.170
245.495
88.202
134.420
152.660
193.680
220.640
260.345
85.024
132.365
151.545
193.555
220.39
258.470
90.876
133.010
154.745
197.285
224.110
263.690

52.970
178.506
51.352
186.962
48.908
192.815
29.770
84.658
126.278
179.058
29.880
83.815
125.490
188.580
31.474
84.273
119.048
182.373
25.064
71.282
89.522
130.542
157.502
197.207
21.272
68.613
87.793
129.803
156.638
194.718
27.726
69.860
91.595
134.135
160.960
200.540

52.970
125.536
51.352
135.610
48.908
143.907
29.770
54.888
41.620
52.780
29.880
53.935
41.675
63.090
31.474
52.799
34.775
63.325
25.064
46.218
18.240
41.020
26.960
39.705
21.272
47.341
19.180
42.010
26.835
38.080
27.726
42.134
21.735
42.540
26.825
39.580

height volume mass dry
Db
[g/cm3
]
[cm]
[cm3]
[g]
3.1
2.7
3.0
2.9
3.0
3.0
1.5
1.5
1.7
1.3
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.1
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.2
1.0
0.9
1.0
1.1
1.0

115.86
100.91
112.12
108.38
112.12
112.12
56.06
56.06
63.54
48.59
56.06
56.06
56.06
56.06
56.06
56.06
56.06
56.06
41.11
37.37
37.37
37.37
37.37
37.37
37.37
37.37
37.37
37.37
37.37
37.37
44.85
37.37
33.64
37.37
41.11
37.37

10.94
88.81
10.78
96.68
10.36
102.92
4.73
38.81
7.60
37.68
5.59
38.43
7.59
45.13
5.95
37.22
6.96
45.07
5.05
32.74
4.00
28.87
5.67
27.76
4.48
33.29
4.10
29.58
4.69
27.22
5.42
29.26
4.92
30.08
5.12
28.18

0.0944
0.8800
0.0961
0.8920
0.0924
0.9180
0.0844
0.6923
0.1197
0.7756
0.0998
0.6855
0.1354
0.8051
0.1061
0.6638
0.1242
0.8039
0.1230
0.8761
0.1071
0.7725
0.1518
0.7429
0.1200
0.8908
0.1096
0.7916
0.1256
0.7282
0.1207
0.7829
0.1463
0.8048
0.1245
0.7540

103

TABLE 41: Db and statistics for Kraft mill sludge-soil layer systems;
1, 2, and 3 layer systems (n=3)

sample

1_

D

>

<D

>>

eg

a)

>*
J5
CO

sludge ( 1 / 1 )
sludge (2/1)
sludge (3/1)
soil (1/1)
soil (2/1)
soil (3/1)
sludge (1/1)
sludge (2/1)
sludge (3/1)
soil (1/1)
soil (2/1)
soil (3/1)
sludge (1/2)
sludge (2/2)
sludge (3/2)
soil (1/2)
soil (2/2)
soil (3/2)
sludge (1/1)
sludge (2/1)
sludge (3/1)
soil (1/1)
soil (2/1)
soil (3/1)
sludge (1/2)
sludge (2/2)
sludge (3/2)
soil (1/2)
soil (2/2)
soil (3/2)
sludge (1/3)
sludge (2/3)
sludge (3/3)
soil (1/3)
soil (2/3)
soil (3/3)

Db
[g/cm3]
0.0741
0.1116
0.0648
0.9287
0.8844
0.9341
0.0591
0.0646
0.0606
0.9371
0.7745
0.8082
0.0655
0.0789
0.0743
1.0289
0.8295
0.9656
0.0700
0.0878
0.0723
0.6582
0.6868
0.6859
0.1386
0.1035
0.1001
0.8256
0.7632
0.8423
0.0995
0.0976
0.0887
1.1793
1.0410
0.8382

average

stdev

TABLE 42: Db and statistics for BCTMP sludge-soil layer systems;
1, 2, and 3 layer systems (n=3)

± se

sample

Db
[g/cm3]

sludge (1/1)
sludge (2/1)
sludge (3/1)
soil (1/1)
soil (2/1)
soil (3/1)
sludge (1/1)
sludge (2/1)
sludge (3/1)
soil (1/1)
soil (2/1)
soil (3/1)
sludge (1/2)
sludge (2/2)
sludge (3/2)
soil (1/2)
soil (2/2)
soil (3/2)
sludge (1/1)
sludge (2/1)
sludge (3/1)
soil (1/1)
soil (2/1)
soil (3/1)
sludge (1/2)
sludge (2/2)
sludge (3/2)
soil (1/2)
soil (2/2)
soil (3/2)
sludge (1/3)
sludge (2/3)
sludge (3/3)
soil (1/3)
soil (2/3)
soil (3/3)

0.0944
0.0961
0.0924
0.8800
0.8920
0.9180
0.0844
0.0998
0.1061
0.6923
0.6855
0.6638
0.1197
0.1354
0.1242
0.7756
0.8051
0.8039
0.1230
0.1200
0.1207
0.8761
0.8908
0.7829
0.1071
0.1096
0.1463
0.7725
0.7916
0.8048
0.1518
0.1256
0.1245
0.7429
0.7282
0.7540

(n=3)
1_

0.084

0.025

0.014

CD

>*
CD

0.916

0.027

0.016

0.061

0.003

0.002

0.840

0.086

0.050

0.073

0.007

0.004

0.941

0.102

0.059

0.077

0.010

0.006

0.677

0.016

0.009

0.114

0.021

0.012

2 layer

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix H: Determination of gravimetric water holding capacity

CD

TO
CO

0.810

0.042

0.024

0.095

0.006

0.003

1.019

0.172

0.099

average
(ii=3)

stdev

± se

0.094

0.002

0.001

0.897

0.019

0.011

0.097

0.011

0.006

0.681

0.015

0.009

0.126

0.008

0.005

0.795

0.017

0.010

0.121

0.002

0.001

0.850

0.059

0.034

0.121

0.022

0.013

0.790

0.016

0.009

0.134

0.015

0.009

0.742

0.013

0.007

104

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix H: Determination of gravimetric water holding capacity

P a rt B : Gravimetric moisture content after soaking and draining = WHCg

TABLE 43: W HCg of sludge and soil samples; (n = 10)

sample
Kraft mill 1a
Kraft mill 1b
Kraft mill 2a
Kraft mill 2b
Kraft mill 3a
Kraft mill 3b
Kraft mill 4a
Kraft mill 4b
Kraft mill 5a
Kraft mill 5b
BCTMP 1a
BCTMP 1b
BCTMP 2a
BCTMP 2b
BCTMP 3a
BCTMP 3b
BCTMP 4a
BCTMP 4b
BCTMP 5a
BCTMP 5b
Soil 1a
Soil 1b
Soil 2a
Soil 2b
Soil 3a
Soil 3b
Soil 4a
Soil 4b
Soil 5a
Soil 5b

container cont. & sludge wet sludge wet cont. & sludge dry sludge dry WHCg average stdev ± se

[g]

[g]

[g]

[g]

[g]

3.142
3.162
3.152
3.128
3.132
3.147
3.130
3.161
3.759
3.148
3.146
3.166
3.154
3.130
3.133
3.148
3.132
3.164
3.761
3.151
3.121
3.152
3.148
3.142
3.170
3.144
3.136
3.132
3.143
3.144

15.373
18.439
19.129
21.650
18.972
22.204
22.514
20.194
24.393
23.441
13.350
12.416
12.655
13.203
15.946
14.897
15.702
15.168
17.100
15.177
32.014
28.636
28.354
30.892
29.569
28.226
34.303
31.474
27.560
28.162

12.231
15.277
15.977
18.522
15.840
19.057
19.384
17.033
20.634
20.293
10.204
9.250
9.501
10.073
12.813
11.749
12.570
12.004
13.339
12.026
28.893
25.484
25.206
27.750
26.399
25.082
31.167
28.342
24.417
25.018

5.264
5.652
5.818
6.215
5.742
6.336
6.129
6.034
7.039
6.355
5.242
5.095
5.200
5.282
5.751
5.538
5.665
5.576
6.286
5.422
24.751
22.371
22.450
24.635
23.046
21.926
26.534
24.155
21.803
22.468

2.122
2.490
2.666
3.087
2.610
3.189
2.999
2.873
3.280
3.207
2.096
1.929
2.046
2.152
2.618
2.390
2.533
2.412
2.525
2.271
21.630
19.219
19.302
21.493
19.876
18.782
23.398
21.023
18.660
19.324

[%]
476
514
499
500
507
498
546
493
529
533
387
380
364
368
389
392
396
398
428
430
34
33
31
29
33
34
33
35
31
29

[%]

509

21.12

6.68

393

21.83

6.90

32

1.92

0.61

105

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix H: Determination of gravimetric water holding capacity
TABLE 44: W H C g of Kraft mill sludge-soil mixtures; (n = 6)

sample
Kraft mill/so I 10:40 1a
Kraft mill/so I 10:40 1b
Kraft mill/so I 10:40 2a
Kraft mill/so I 10:40 2b
Kraft mill/so I 10:40 3a
Kraft mill/so I 10:40 3b
Kraft mill/so I 20:30 1a
Kraft mill/so I 20:30 1b
Kraft mill/so I 20:30 2a
Kraft mill/so I 20:30 2b
Kraft mill/so I 20:30 3a
Kraft mill/so I 20:30 3b
Kraft mill/so I 25:25 1a
Kraft mill/so I 25:25 1b
Kraft mill/so I 25:25 2a
Kraft mill/so I 25:25 2b
Kraft mill/so I 25:25 3a
Kraft mill/so I 25:25 3b
Kraft mill/so I 30:20 1a
Kraft mill/so I 30:20 1b
Kraft mill/so I 30:20 2a
Kraft mill/so I 30:20 2b
Kraft mill/so I 30:20 3a
Kraft mill/so I 30:20 3b
Kraft mill/so 140:10 1a
Kraft mill/so 140:10 1b
Kraft mill/so 140:10 2a
Kraft mill/so 140:10 2b
Kraft mill/so 140:10 3a
Kraft mill/so 140:10 3b
Kraft mil orig.blend 1a
Kraft mill orig.blend 1b
Kraft mill orig.blend 2a
Kraft mill orig.blend 2b
Kraft mill orig.blend 3a
Kraft mill orig.blend 3b

container cont. & sludge wet sludge wet cont. & sludge dry sludge dry WHCg average stdev ± se

[g]

[g]

[g]

[g]

[g]

3.130
3.161
3.759
3.147
3.121
3.155
3.142
3.161
3.152
3.127
3.132
3.147
3.141
3.161
3.152
3.128
3.132
3.144
3.169
3.170
3.220
3.171
3.222
3.186
3.133
3.166
3.772
3.156
3.212
3.177
3.133
3.148
3.154
3.160
3.145
3.165

17.776
16.330
15.470
14.895
12.825
13.328
13.445
13.549
12.686
12.414
12.917
15.150
11.023
10.429
13.651
10.872
12.248
11.506
12.288
12.337
14.938
14.270
16.978
13.240
14.646
14.343
17.755
17.241
13.355
12.861
13.315
16.111
14.179
14.153
16.975
15.975

14.646
13.169
11.711
11.748
9.704
10.173
10.303
10.388
9.534
9.287
9.785
12.003
7.882
7.268
10.499
7.744
9.116
8.362
9.119
9.167
11.718
11.099
13.756
10.054
11.513
11.177
13.983
14.085
10.143
9.684
10.182
12.963
11.025
10.993
13.830
12.810

12.154
11.069
10.822
10.299
8.383
10.026
6.877
7.260
7.052
6.811
8.118
8.790
6.460
5.679
8.124
5.984
7.102
6.705
5.932
5.885
7.287
5.966
7.075
5.709
5.528
5.067
6.199
5.530
5.243
4.955
4.395
4.689
4.506
4.484
4.898
4.808

9.024
7.908
7.063
7.152
5.262
6.871
3.735
4.099
3.900
3.684
4.986
5.643
3.319
2.518
4.972
2.856
3.970
3.561
2.763
2.715
4.067
2.795
3.853
2.523
2.395
1.901
2.427
2.374
2.031
1.778
1.262
1.541
1.352
1.324
1.753
1.643

[%]
62
67
66
64
84
48
176
153
144
152
96
113
137
189
111
171
130
135
230
238
188
297
257
298
381
488
476
493
399
445
707
741
715
730
689
680

[%]

65

11.62

4.74

139

29.28

11.95

145

28.74

11.73

251

42.40

17.31

447

47.61

19.44

710

23.61

9.64

106

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix H: Determination of gravimetric water holding capacity
TABLE 45: W H C g of BCTMP sludge-soil mixtures; (n = 6)

sample
BCTMP/so I 10:40; 1a
BCTMP/so I 10:40; 1b
BCTMP/so I 10:40; 2a
BCTMP/so I 10:40; 2b
BCTMP/so I 10:40; 3a
BCTMP/so I 10:40; 3b
BCTMP/so 120:30; 1a
BCTMP/so I 20:30; 1b
BCTMP/so I 20:30; 2a
BCTMP/so I 20:30; 2b
BCTMP/so I 20:30; 3a
BCTMP/so I 20:30; 3b
BCTMP/so I 25:25; 1a
BCTMP/so 125:25; 1b
BCTMP/so I 25:25; 2a
BCTMP/so I 25:25; 2b
BCTMP/so I 25:25; 3a
BCTMP/so I 25:25; 3b
BCTMP/so I 30:20; 1a
BCTMP/so I 30:20; 1b
BCTMP/so I 30:20; 2a
BCTMP/so I 30:20; 2b
BCTMP/so I 30:20; 3a
BCTMP/so I 30:20; 3b
BCTMP/so 140:10; 1a
BCTMP/so 140:10; 1b
BCTMP/so I 40:10; 2a
BCTMP/so 140:10; 2b
BCTMP/so 140:10; 3a
BCTMP/so 140:10; 3b
BCTMP orig. blend 1a
BCTMP orig. blend 1b
BCTMP orig. blend 2a
BCTMP orig. blend 2b
BCTMP orig. blend 3a
BCTMP orig. blend 3b

container cont. & sludge wet sludge wet cont. & sludge dry sludge dry WHCg average stdev ± se

[g]

[g]

[g]

[g]

[g]

3.142
3.162
3.151
3.128
3.132
3.144
3.131
3.162
3.757
3.147
3.120
3.154
3.131
3.162
3.757
3.147
3.120
3.153
3.145
3.144
3.171
3.145
3.136
3.131
3.141
3.162
3.757
3.147
3.121
3.154
3.142
3.163
3.152
3.128
3.133
3.144

13.089
13.402
14.856
14.999
14.645
13.898
15.178
14.855
13.841
12.515
15.816
14.323
13.639
11.977
14.415
12.982
12.965
11.057
15.225
15.268
12.670
12.614
10.063
14.901
10.362
11.991
12.415
11.050
11.556
10.775
10.828
11.387
11.528
11.082
10.455
11.628

9.947
10.240
11.705
11.871
11.513
10.754
12.047
11.693
10.084
9.368
12.696
11.169
10.508
8.815
10.658
9.835
9.845
7.904
12.080
12.124
9.499
9.469
6.927
11.770
7.221
8.829
8.658
7.903
8.435
7.621
7.686
8.224
8.376
7.954
7.322
8.484

9.921
9.820
10.771
10.803
10.768
10.226
9.296
8.950
9.269
7.890
10.760
9.345
8.146
7.172
8.969
7.866
8.240
6.915
7.609
7.444
6.407
6.463
5.890
7.290
5.048
5.446
5.878
5.041
5.411
5.036
4.402
4.516
4.481
4.391
4.300
4.516

6.779
6.658
7.620
7.675
7.636
7.082
6.165
5.788
5.512
4.743
7.640
6.191
5.015
4.010
5.212
4.719
5.120
3.762
4.464
4.300
3.236
3.318
2.754
4.159
1.907
2.284
2.121
1.894
2.290
1.882
1.260
1.353
1.329
1.263
1.167
1.372

[%]
47
54
54
55
51
52
95
102
83
98
66
80
110
120
104
108
92
110
171
182
194
185
152
183
279
287
308
317
268
305
510
508
530
530
527
518

[%]

52

2.90

1.19

87

13.41

5.48

107

8.99

3.67

178

14.78

6.03

294

19.04

7.77

521

10.04

4.10

107

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix H: Determination of gravimetric water holding capacityy
TABLE 46: W H C g of Kraft mill sludge-soil layer systems; 1,2, and 3 layer systems (n = 6)

sample
sludge (1/1/a)
sludge (1/1 /b)
sludge (2/1/a)
L_
sludge (2/1/b)
CD
03 sludge (3/1 la)
T—
sludge (3/1/b)
E soil (1/1/a)
soil (1/1 lb)
CD
soil (2/1/a)
soil (2/1/b)
soil (3/1/a)
soil (3/1/b)
sludge (1/1/a)
sludge (1/1/b)
sludge (2/1/a)
sludge (2/1/b)
sludge (3/1/a)
sludge (3/1/b)
sludge (1/2/a)
sludge (1/2/b)
sludge (2/2/a)
CO
L_
o sludge (2/2/b)
JD
sludge (3/2/a)
CNJ
sludge (3/2/b)
soil
(1/1/a)
E
soil (1/1/b)
CD
L_
soil (2/1/a)
soil (2/1/b)
soil (3/1/a)
soil (3/1/b)
soil (1/2/a)
soil (1/2/b)
soil (2/2/a)
soil (2/2/b)
soil (3/2/a)
soil (3/2/b)

container cont. & sludge wet sludge wet cont. & sludge dry sludge dry

[g]

[g]

[g]

[g]

[g]

3.154
3.129
3.132
3.162
3.120
3.153
3.143
3.164
3.132
3.144
3.756
3.146
3.133
3.161
3.759
3.164
3.146
3.134
3.133
3.124
3.140
3.133
3.146
3.145
3.142
3.180
3.155
3.158
3.147
3.155
3.164
3.175
3.146
3.158
3.186
3.153

10.202
10.095
10.977
10.31
10.161
10.17

7.048
6.966
7.845
7.148
7.041
7.017
15.758
16.985
16.066
17.081
17.006
21.281
5.133
4.465
4.320
4.668
4.446
4.701
3.650
3.888
4.550
4.997
5.005
5.078
9.820
10.645
8.249
7.397
9.940
10.697
10.525
10.272
8.908
9.058
10.212
10.315

4.744
4.811
6.285
4.839
4.477
4.456
14.469
15.596
14.571
15.279
15.969
18.364
4.080
3.908
4.533
3.977
3.822
3.924
3.781
3.824
3.871
3.944
3.975
3.99
10.381
10.953
9.082
8.482
10.333
10.999
10.736
10.620
9.532
9.655
10.513
10.562

1.590
1.682
3.153
1.677
1.357
1.303
11.326
12.432
11.439
12.135
12.213
15.218
0.947
0.747
0.774
0.813
0.676
0.700
0.648
0.700
0.731
0.811
0.829
0.845
7.239
7.773
5.927
5.324
7.186
7.844
7.572
7.445
6.386
6.497
7.327
7.409

18.901
20.149
19.198
20.225
20.762
24.427
8.266
7.626
8.079
7.832
7.592
7.835
6.783
7.012
7.69
8.13
8.151
8.223
12.962
13.825
11.404
10.555
13.087
13.852
13.689
13.447
12.054
12.216
13.398
13.468

WHCg
[%]
343
314
149
326
419
439
39
37
40
41
39
40
442
498
458
474
558
495
463
455
522
516
504
501
36
37
39
39
38
36
39
38
39
39
39
39

average stdev

± se

[%]

332

103

42.0

39

1.48

0.60

487

40.5

16.5

494

27.8

11.4

38

1.45

0.59

39

0.57

0.23

108

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix H: Determination of gravimetric water holding capacityy

sample

tn

0

ro
n

I
ro
L_

sludge (1/1/a)
sludge (1/1/b)
sludge (2/1/a)
sludge (2/1/b)
sludge (3/1/a)
sludge (3/1/b)
sludge (1/2/a)
sludge (1/2/b)
sludge (2/2/a)
sludge (2/2/b)
sludge (3/2/a)
sludge (3/2/b)
sludge (1/3/a)
sludge (1/3/b)
sludge (2/3/a)
sludge (2/3/b)
sludge (3/3/a)
sludge (3/3/b)
soil (1/1/a)
soil (1/1/b)
soil (2/1/a)
soil (2/1/b)
soil (3/1/a)
soil (3/1/b)
soil (1/2/a)
soil (1/2/b)
soil (2/2/a)
soil (2/2/b)
soil (3/2/a)
soil (3/2/b)
soil (1/3/a)
soil (1/3/b)
soil (2/3/a)
soil (2/3/b)
soil (3/3/a)
soil (3/3/b)

container cont. & sludge wet sludge wet cont. & sludge dry sludge dry

[g]

[g]

[g]

[g]

[g]

3.133
3.163
3.139
3.133
3.165
3.152
3.129
3.120
3.142
3.130
3.148
3.150
3.757
3.163
3.141
3.142
3.108
3.146
3.132
3.147
3.136
3.150
3.145
3.128
3.151
3.153
3.134
3.142
3.148
3.142
3.141
3.142
3.170
3.144
3.150
3.137

6.452
6.617
8.747
8.566
11.057
10.783
8.558
8.538
9.568
8.998
7.642
7.334
7.433
7.258
8.485
8.483
7.738
8.193
9.768
7.819
11.632
10.567
8.649
9.431
9.436
9.737
13.604

3.319
3.454
5.608
5.433
7.892
7.631
5.429
5.418
6.426
5.868
4.494
4.184
3.676
4.095
5.344
5.341
4.630
5.047
6.636
4.672
8.496
7.417
5.504
6.303
6.285
6.584
10.470
9.588
6.033
6.207
7.306
7.445
8.710
8.896
5.948
6.045

3.730
3.762
4.108
4.053
4.444
4.424
4.406
4.339
4.404
4.269
4.024
4.040
4.324
4.080
4.175
4.150
4.018
4.084
7.945
6.555
9.363
8.669
7.201
7.842
7.790
7.972
10.667
10.041
7.470
7.613
8.448
8.566
9.404
9.549
7.444
7.508

0.597
0.599
0.969
0.920
1.279
1.272
1.277
1.219
1.262
1.139
0.876
0.890
0.567
0.917
1.034
1.008
0.910
0.938
4.813
3.408
6.227

12.730
9.181
9.349
10.447
10.587
11.880
12.040
9.098
9.182

5.519
4.056
4.714
4.639
4.819
7.533
6.899
4.322
4.471
5.307
5.424
6.234
6.405
4.294
4.371

WHCg
[%]
456
477
479
491
517
500
325
344
409
415
413
370
548
347
417
430
409
438
38
37
36
34
36
34
35
37
39
39
40
39
38
37
40
39
39
38

average stdev

± se

[%]

486

21.1

8.60

380

38.9

15.9

431

65.8

26.9

36

1.60

0.65

38

1.63

0.67

38

0.88

0.36

109

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix H: Determination of gravimetric water holding capacityy
TABLE 47: W H C g of B C TM P sludge-soil layer systems; 1, 2, and 3 layer systems (n = 6)

sample
sludge (1/1/a)
sludge (1/1/b)
sludge (2/1 /a)
<x> sludge (2/1/b)
sludge (3/1/a)
sludge (3/1/b)
Q.
soil (1/1/a)
I— soil (1/1/b)
o
CQ
soil (2/1/a)
soil (2/1/b)
soil (3/1/a)
soil (3/1/b)
sludge (1/1/a)
sludge (1/1/b)
sludge (2/1/a)
sludge (2/1/b)
sludge (3/1/a)
sludge (3/1/b)
sludge (1/2/a)
sludge (1/2/b)
sludge (2/2/a)
V/J
i_
sludge (2/2/b)
CD
>%
ro
sludge (3/2/a)
CM
sludge (3/2/b)
CL soil (1/1/a)
I— soil (1/1/b)
o
00 soil (2/1/a)
soil (2/1/b)
soil (3/1/a)
soil (3/1/b)
soil (1/2/a)
soil (1/2/b)
soil (2/2/a)
soil (2/2/b)
soil (3/2/a)
soil (3/2/b)

container cont. & sludge wet sludge wet cont. & sludge dry sludge dry

[g]

[g]

[g]

[g]

[g]

3.152
3.127
3.129
3.161
3.120
3.153
3.143
3.163
3.131
3.143
3.756
3.146
3.131
3.161
3.758
3.164
3.141
3.131
3.127
3.120
3.139
3.131
3.143
3.144
3.130
3.147
3.142
3.144

10.210
10.111
10.174
10.571
10.068
10.265
18.085
19.77
21.906
19.758
22.243
20.976
7.340
6.976
8.359
8.501
8.240
8.616
10.892
11.821
9.421
10.932
9.814
10.084
9.771
9.83
10.137
9.388

3.135
3.145
3.155
3.153
3.135
3.150
3.170
3.144

10.891
11.256
9.939
9.855
10.178
9.717
10.601
10.299

7.058
6.984
7.045
7.410
6.948
7.112
14.942
16.607
18.775
16.615
18.487
17.830
4.209
3.815
4.601
5.337
5.099
5.485
7.765
8.701
6.282
7.801
6.671
6.940
6.641
6.683
6.995
6.244
7.756
8.111
6.784
6.702
7.043
6.567
7.431
7.155

4.646
4.533
4.603
4.721
4.594
4.658
13.630
14.994
16.449
15.055
16.954
15.922
3.929
3.638
4.615
4.167
4.109
4.164
4.488
4.767
4.216
4.619
4.498
4.515
7.808
7.890
8.147
7.572
8.662
8.802
7.972
7.964
8.177
7.844
8.529
8.166

1.494
1.406
1.474
1.560
1.474
1.505
10.487
11.831
13.318
11.912
13.198
12.776
0.798
0.477
0.857
1.003
0.968
1.033
1.361
1.647
1.077
1.488
1.355
1.371
4.678
4.743
5.005
4.428
5.527
5.657
4.817
4.811
5.042
4.694
5.359
5.022

WHCg
[%]
372
397
378
375
371
373
42
40
41
39
40
40
427
700
437
432
427
431
471
428
483
424
392
406
42
41
40
41
40
43
41
39
40
40
39
42

average stdev

± se

[%]

378

9.63

3.93

40

1.12

0.46

476

110

44.9

434

35.8

14.6

41

1.29

0.53

40

1.35

0.55

110

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix H: Determination of gravimetric water holding capacityy

sample
sludge (1/1/a)
sludge (1/1/b)
sludge (2/1/a)
sludge (2/1/b)
sludge (3/1/a)
sludge (3/1/b)
sludge (1/2/a)
sludge (1/2/b)
sludge (2/2/a)
sludge (2/2/b)
sludge (3/2/a)
sludge (3/2/b)
sludge (1/3/a)
sludge (1/3/b)
sludge
(2/3/a)
iC/5
_
sludge (2/3/b)
CD
TO sludge (3/3/a)
co sludge (3/3/b)
Q .
soil (1/1/a)
1
—
soil (1/1/b)
t \
co soil (2/1/a)
soil (2/1/b)
soil (3/1/a)
soil (3/1/b)
soil (1/2/a)
soil (1/2/b)
soil (2/2/a)
soil (2/2/b)
soil (3/2/a)
soil (3/2/b)
soil (1/3/a)
soil (1/3/b)
soil (2/3/a)
soil (2/3/b)
soil (3/3/a)
soil (3/3/b)

container cont. & sludge wet sludge wet cont. & sludge dry sludge dry

[g]

[g]

[g]

[g]

[g]

3.131
3.161
3.140
3.141
3.169
3.155
3.128
3.119
3.140
3.131
3.153
3.155
3.757
3.164
3.143
3.143
3.115
3.140
3.133
3.148
3.135
3.152
3.151
3.132
3.154
3.154
3.135
3.145
3.155
3.147
3.143
3.144
3.170
3.143
3.154
3.153

7.162
7.346
7.105
7.628
9.678
9.175
7.306
6.861
8.554
9.004
9.746
10.748
8.650
7.057
8.346
8.312
9.184
8.618
7.516
7.250
9.039
9.630
6.614
7.533
6.831
6.494
7.697
8.743
7.608
7.818
7.008
7.306
8.021
7.924
7.416
8.390

4.031
4.185
3.965
4.487
6.509
6.020
4.178
3.742
5.414
5.873
6.593
7.593
4.893
3.893
5.203
5.169
6.069
5.478
4.383
4.102
5.904
6.478
3.463
4.401
3.677
3.340
4.562
5.598
4.453
4.671
3.865
4.162
4.851
4.781
4.262
5.237

3.947
4.002
3.981
4.082
4.422
4.349
4.044
3.941
4.416
4.266
4.619
4.901
4.790
3.980
4.051
4.049
4.281
4.178
6.221
6.071
7.291
7.704
5.577
6.167
5.763
5.484
6.321
7.114
6.281
6.472
5.856
6.044
6.652
6.545
6.186
6.884

0.816
0.841
0.841
0.941
1.253
1.194
0.916
0.822
1.276
1.135
1.466
1.746
1.033
0.816
0.908
0.906
1.166
1.038
3.088
2.923
4.156
4.552
2.426
3.035
2.609
2.330
3.186
3.969
3.126
3.325
2.713
2.900
3.482
3.402
3.032
3.731

WHCg
[%]
394
398
371
377
419
404
356
355
324
417
350
335
374
377
473
471
420
428
42
40
42
42
43
45
41
43
43
41
42
40
42
44
39
41
41
40

average stdev

± se

[%]

394

17.7

7.23

356

32.5

13.2

424

43.19

17.6

42

1.52

0.62

42

1.24

0.51

41

1.55

0.63

111

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment

Part A: Moisture retention curves for sludge and soil samples

sample height:
sample diameter:
sample volume:

1.0 cm
6.9 cm
3 7.37 car3

Ah
Ad
Am

0.02 cm
0.02 cm
0.001 g

TABLE 48: Raw data for moisture retention curve of Kraft mill sludge (n=1)

cont.&sludge wet sludge wet cont.&sludge dry sludge dry

pressure
[bar]

container

[g]

[g]

[g]

[g]

[g]

0.1
0.2
0.3
0.4
0.5
0.7
1.0
2.0
5.0
10.0
15.0

3.815
3.816
3.818
3.815
3.815
3.815
3.818
3.818
3.818
3.815
3.816

30.600
24.877
22.025
23.176
20.825
20.616
20.614
19.824
23.734
23.112
23.237

26.785
21.061
18.207
19.361
17.010
16.801
16.796
16.006
19.916
19.297
19.421

8.615
9.060
8.294
8.798
8.314
8.142
8.622
8.468
9.490
9.819
9.739

4.800
5.244
4.476
4.983
4 .499
4.327
4.804
4.650
5.672
6.004
5.923

WHCg
[%]
458
302
307
289
278
288
250
244
251
221
228
average
stdev
se

bulk density
[g/cmJ]
0.128
0.140
0.120
0.133
0.120
0.116
0.129
0.124
0.152
0.161
0.158

WHCV
[%]
58.8
42.3
36.7
38.5
33.5
33.4
32.1
30.4
38.1
35.6
36.1

0 .13 47
0.0159
± 0.0048

112

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment

TABLE 49: Raw data for moisture retention curve of B C TM P sludge (n=1)

cont.&sludge wet sludge wet cont.&sludge dry sludge dry

pressure
[bar]

container

[g]

[g]

[g]

[g]

[g]

0.1
0.2
0.3
0.4
0.5
0.7
1.0
2.0
5.0
10.0
15.0

3.828
3.830
3.826
3.829
3.828
3.828
3.827
3.828
3.830
3.829
3.829

26.992
28.638
29.360
27.433
25.878
25.501
25.467
26.015
27.232
25.041
23.578

23.164
24.808
25.534
23.604
22.050
21.673
21.640
22.187
23.402
21.212
19.749

8.439
8.893
9.293
8.922
8.633
8.494
8.510
8.649
8.969
10.012
9.689

4.611
5.063

[%]
402
390

5.467
5.093
4.805
4.666
4.683
4.821
5.139

367
363
359
364
362
360
355

6.183
5.860

243
237
average
stdev
se

cont.& soil dry

soil dry

WHCg

bulk density
[g/cm3]
0.123
0.135
0.146
0.136
0.129
0.125
0.125
0.129
0.138
0.165
0.157
0.1372
0.0138
± 0.0041

WHCV
[%]
49.6
52.8
53.7
49.5
46.1
45.5
45.4
46.5
4 8.9
40.2
37.2

TABLE 50: Raw data for moisture retention curve of soil (n=1)

pressure
[bar]

container

cont.& soil wet

[g]

[g]

[g]

[g]

[g]

0.1
0.2
0.3
0.4
0.5
0.7
1.0
2.0
5 .0
10.0
15.0

3.783
3.807
3.785
3.805

73.136
73.758
65.080
74.858

69.353
69.951
61.295
71.053

53.635
56.920

3.785
3.783
3.785
3.785
3.815
3.812
3.823

58.519
63.518

54.734
59.735

46.652
50.334

70.530
71.218
73.182
71.224
70.398

66.745
67.433
69.367
67.412
66.575

56.315
5 7.660

49.852
53.113
46.657
54.264
42.867
46.551
52.530
53.875
54.299

soil wet

50.442
58.069

58.114
58.126
57.414

54.314
53.591

WHCg
[%]
39
32
31
31
28
28
27
25
28
24
24
average
stdev
se

bulk density
[g/cm3]
1.334
1.421
1.249
1.452
1.147
1.246
1.406
1.442
1.453
1.453
1.434
1.3670
0.1072
± 0.0323

WHCV
[%]
52.2
45.1
39.2
44.9
31.8
35.3
38.0
36.3
40.3
35.0
34.7

113

Appendix I: Pressure Plate Experiment
TABLE 51: Determination of random errors of bulk density, gravimetric (W H C g) and
volumetric moisture content (W H C V) for Kraft mill sludge.
pressure
[bar]
0.1
0.2
0.3
0.4
0.5
0.7
1.0
2.0
5.0
10.0
15.0

m ass w et m ass dry

[g]

[g]

26.785
21.061
18.207
19.361
17.010

4.800
5.244

WHCg

16.801
16.796
16.006
19.916
19.297

4.476
4.983
4.499
4.327
4.804
4.650
5.672
6.004

[%]
458
302
307
289
278
288
250
244
251
221

19.421

5.923

228

± AWHCg
0.141
0.090
0.107
0.091
0.098
0.105
0.084
0.086
0.072
0.062
0.064

Db
[g/cm 3]
0.128
0.140
0.120
0.133
0.120
0.116
0.129
0.124
0.152
0.161
0.158

± ADb
0.0026
0.0029
0.0024
0.0027
0.0025
0.0024
0.0026
0.0025
0.0031
0.0033
0.0032

WHCV
[%]
58.8
42.3
36.7
38.5
33.5
33.4
32.1
30.4
38.1
35.6
36.1

± AWHCV
1.201
0.864
0.750
0.786
0.684
0.682
0.655
0.621
0.778
0.726
0.737

TABLE 52: Determination of random errors of bulk density, gravimetric (W H C g) and
volumetric moisture content (W H C V) for BCTM P sludge.
pressure
[bar]
0.1
0.2
0.3
0.4
0.5
0.7
1.0
2.0
5.0
10.0
15.0

m ass w e t m ass dry

[g]

[g]

23.164
24.808
25.534
23.604
22.050
21.673
21.640
22.187
23.402

4.611
5.063
5.467
5.093
4.805
4.666
4.683
4.821
5.139
6.183
5.860

21.212
19.749

WHCg

+ AWHCg

[%]
402
390
367
363
359
364
362

0.131
0.116
0.102
0.108
0.114
0.118
0.117

360
355
243
237

0.114
0.105
0.064
0.067

Db
[g/cm 3]
0.123
0.135
0.146
0.136
0.129
0.125
0.125
0.129
0.138
0.165
0.157

+ ADb

WHCV + AWHCV

0.0025
0.0028
0.0030
0.0028
0.0026
0.0025
0.0026

[%]
49.6
52.8
53.7
49.5
46.1
45.5
45.4

1.014
1.079
1.096
1.011
0.942
0.929
0.927

0.0026
0.0028
0.0034
0.0032

46.5
48.9
40.2
37.2

0.949
0.998
0.821
0.759

TABLE 53: Determination of random errors of bulk density, gravimetric (W H C g) and
volumetric moisture content (W H C V) for soil.
pressure
[bar]
0.1
0.2
0.3
0.4
0.5
0.7
1.0
2.0
5.0
10.0
15.0

m ass w et m ass dry

[g]

[g]

69.353
69.951
61.295
71.053
54.734
59.735
66.745
67.433
69.367
67.412
66.575

49.85
53.11
46.66
54.26
42.87
46.55
52.53
53.88
54.30
54.31
53.59

WHCg

± AWHCg

Db

+ ADb

WHCV ± AWHCV

[%]
39.1
31.7
31.4
30.9
27.7
28.3
27.1
25.2
27.8
24.1
24.2

0.0042
0.0039
0.0044
0.0038
0.0048
0.0044
0.0039
0.0038
0.0038
0.0037
0.0038

[g/cm 3]
1.334
1.421
1.249
1.452
1.147
1.246
1.406
1.442
1.453
1.453
1.434

0.0272
0.0290
0.0255
0.0296
0.0234
0.0254
0.0287
0.0294
0.0297
0.0297
0.0293

[%]
52.2
45.1
39.2
44.9
31.8
35.3
38.0
36.3
40.3
35.0
34.7

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

1.065
0.920
0.800
0.917
0.648
0.720
0.777
0.741
0.823
0.716
0.709

Appendix I: Pressure Plate Experiment

Part B: Moisture retention curves for sludge-soil mixtures

Table 54: Raw data for moisture retention curve of Kraft mill sludge
pressure
[bar]

0.1
0.3
0.3
0.3
0.5
0.7
1.0
1.0
2.0
5.0
10.0
15.0
15.0
15.0

trial

#
1
1
2
3
1
1
1
2
1
1
1
1
2
3

alu em pty & sam ple w et

[g]
3.840
3.840
3.838
3.839
3.651
3.838
3.838
3.650
3.837
3.839
3.650
3.651
3.651
3.651

[g]
27.303
24.055
23.094
23.316
22.122
23.242
21.791
20.380
20.833
22.463
21.673
20.899
20.953
20.686

m ass w e t & sam ple dry

[g]
23.463
20.215
19.256
19.477
18.471
19.404
17.953
16.730
16.996
18.624
18.023
17.248
17.302
17.035

[g]
8.591
8.925
8.816
8.756
8.719
9.071
8.881
8.255
8.769
9.146
8.859
8.629
8.880
8.573

m ass dry

[g]
4.751
5.085
4.978
4.917
5.068
5.233
5.043
4.605
4.932
5.307
5.209
4.978
5.229
4.922
average
stdev
±se

Db
[g/cm -5]

0.127
0.136
0.133
0.132
0.136
0.140
0.135
0.123
0.132
0.142
0.139
0.133
0.140
0.132
0.134
0.005
0.001

TABLE 55: Raw data for moisture retention curve of blended Kraft mill sludge
pressure
[bar]

0.1
0.3
0.3
0.3
0.5
0.7
1.0
1.0
2.0
5.0
10.0
15.0
15.0
15.0

trial

#
1
1
2
3
1
1
1
2
1
1
1
1
2
3

alu em p ty & sam p le w et

[g]
3.818
3.819
3.817
3.818
3.582
3.818
3.819
3.582
3.817
3.817
3.582
3.582
3.583
3.582

[g]
33.607
27.716
27.050
26.848
25.263
29.801
28.311
24.965
23.853
24.024
27.963
24.121
23.302
24.359

m ass w e t & sam ple dry

[g]
29.789
23.897
23.233
23.030
21.681
25.983
24.492
21.383
20.036
20.207
24.381
20.539
19.719
20.777

[g]
10.165
9.802
10.293
9.978
9.505
11.124
10.699
9.714
9.611
9.459
11.065
9.971
9.346
9.728

m ass dry

[g]
6.347
5.983
6.476
6.160
5.923
7.306
6.880
6.132
5.794
5.642
7.483
6.389
5.763
6.146
average
stdev
±se

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Db
[g/cm '5]

0.170
0.160
0.173
0.165
0.158
0.196
0.184
0.164
0.155
0.151
0.200
0.171
0.154
0.164
0.169
0.015
0.004

Appendix I: Pressure Plate Experiment

Table 56: Raw data for moisture retention curve of Kraft mill sludge-soil mixture 40:10
pressure

trial

[bar]

#
1
1
2
3
1
1
1
2

0.1
0.3
0.3
0.3
0.5
0.7
1.0
1.0
2.0
5.0
10.0
15.0
15.0
15.0

1
1
1
1
2
3

alu em p ty & sam ple w et

m ass w et & sam ple dry

m ass dry

Db

[g]

[g]

[g]

[g]

[g]

3.699
3.700
3.699
3.701
3.625
3.698
3.700
3.623
3.697
3.701
3.625
3.624
3.625
3.627

34.877
30.793
28.473
29.515
27.321
28.921
28.668
27.561
26.46
28.343
26.025
25.851
26.071
26.107

31.178
27.093
24.774
25.814
23.696

13.435
13.798
12.546
13.731
12.751

9.736
10.098
8.847
10.030
9.126

[g/cm 3]
0.261
0.270
0.237
0.268
0.244

25.223
24.968
23.938
22.763
24.642
22.400
22.227
22.446
22.480

12.639
13.928
12.510
13.023
13.494
13.358
12.872
13.804
13.433

8.941
10.228
8.887
9.326
9.793
9.733
9.248
10.179
9.806
average

0.239
0.274
0.238
0.250
0.262
0.260
0.247
0.272
0.262
0.256

stdev
± se

0.013
0.004

Table 57: Raw data for moisture retention curve of Kraft mill sludge-soil mixture 30:20
pressure

trial

[bar]
0.1
0.3
0.3
0.3
0.5
0.7

#
1
1
2

1.0
1.0
2.0
5.0
10.0
15.0
15.0
15.0

3
1
1
1
2
1
1
1
1
2
3

alu em p ty & sam ple w et

m ass w e t & sam ple d ry

m ass dry

Db

[g]

[g]

[g]

[g]

[g]

3.791
3.794
3.795
3.795
3.651
3.794
3.794
3.650
3.794
3.796
3.650
3.649
3.650
3.652

44.371
37.728
36.299

40.580
33.934
32.504
32.989
31.415
33.467
32.685
31.932
30.262
31.218
30.051
29.704
29.512
29.518

19.024
18.455
19.325
19.269
18.691
18.834
20.018
19.906
19.929
21.299
20.650
19.408
19.266
19.420

15.233
14.661
15.530
15.474
15.040
15.040
16.224
16.256
16.135
17.503
17.000
15.759
15.616
15.768
average
stdev
± se

[g/cm 3]
0.408
0.392
0.416
0.414
0.402
0.402
0.434
0.435
0.432
0.468
0.455
0.422
0.418
0.422
0.423
0.021
0.006

36.784
35.066
37.261
36.479
35.582
34.056
35.014
33.701
33.353
33.162
33.170

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment

Table 58: Raw data for moisture retention curve of Kraft mill sludge-soil mixture 25:25
pressure

trial

[bar]
0.1
0.3
0.3
0.3
0.5
0.7

#
1
1
2
3
1
1
1
2
1
1

1.0
1.0
2.0
5.0
10.0
15.0
15.0
15.0

1
1
2
3

alu em p ty & sam ple w et

m ass w e t & sam ple dry

m ass dry

Db
[g/cm 3]
0.529
0.499
0.553
0.506
0.503
0.504
0.506
0.468
0.514

[g]

[g]

[g]

[g]

[g]

3.822
3.827
3.826
3.828
3.667
3.827
3.827
3.668
3.825

46.694
40.435
40.975
40.682
39.294
36.435
37.500
36.682
36.565
37.565
36.317
34.720
37.142
36.035

23.586
22.469
24.499
22.749
22.460
22.657
22.726
21.166
23.025
23.471

19.764
18.642

3.828
3.668
3.668
3.669
3.671

42.872
36.608
37.149
36.854
35.627
32.608
33.673
33.014
32.740
33.737
32.649
31.052
33.473
32.364

22.594
21.402
23.272
22.488

20.673
18.921
18.793
18.830
18.899
17.498
19.200
19.643
18.926
17.734
19.603
18.817

0.526
0.506
0.475
0.525
0.504

average
stdev
± se

0.508
0.021
0.006

Table 59: Raw data for moisture retention curve of Kraft mill sludge-soil mixture 20:30
pressure

trial

[bar]
0.1
0.3
0.3
0.3
0.5
0.7
1.0
1.0
2.0
5.0
10.0
15.0
15.0
15.0

#
1
1
2
3
1
1
1
2
1
1
1
1
2
3

alu em pty & sam ple w et

m ass w e t & sam ple dry

m ass dry

Db
[g/cm 3]
0.560
0.582

[g]

[g]

[g]

[g]

[g]

3.830
3.834
3.835
3.836
3.681
3.835
3.835
3.681
3.834
3.835
3.682
3.682
3.682
3.683

45.428
43.016
41.378
41.698
40.549
40.022
40.115
38.986
38.082
38.705
38.180
36.438
37.211
37.069

41.598
39.182
37.543
37.862
36.868
36.187
36.280
35.305
34.248
34.870
34.498
32.756
33.529
33.386

24.743
25.589
25.898
25.306
25.568
26.667
25.876
23.899
26.270
26.437
25.097
25.072
25.836
24.949

20.913
21.755
22.063
21.470
21.887
22.832
22.041
20.218
22.436
22.602
21.415
21.390
22.154
21.266
average
stdev
±se

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

0.590
0.575
0.586
0.611
0.590
0.541
0.600
0.605
0.573
0.572
0.593
0.569
0.582
0.019
0.005

Appendix I: Pressure Plate Experiment

Table 60: Raw data for moisture retention curve of Kraft mill sludge-soil mixture 10:40
pressure

trial

[bar]
0.1
0.3
0.3
0.3
0.5
0.7
1.0
1.0
2.0

#
1
1
2
3
1
1
1
2
1

5.0
10.0
15.0
15.0
15.0

1
1
1
2
3

alu em p ty & sam ple w et

m ass w e t & sam ple d ry

m ass dry

Db
[g/cm 3]
0.923
0.918
0.933
0.917
0.918
0.941
0.917
0.927
0.940
0.916
0.910
0.914
0.938
0.936
0.925
0.011
0.003

[g]

[g]

[g]

[g]

[g]

3.819
3.822
3.821
3.821
3.700
3.819
3.820
3.699
3.819
3.822
3.700
3.701
3.700
3.701

59.523
55.832
56.310
55.869
52.806
53.448
52.823
52.143
52.253
50.887
49.894
51.174
52.313
51.748

55.704
52.010
52.489
52.048
49.106
49.629
49.003
48.444
48.434
47.065
46.194
47.473
48.613
48.047

38.295
38.114
38.685
38.099
38.006
38.994
38.100
38.353
38.953
38.045
37.697
37.863
38.738
38.668

34.476
34.292
34.864
34.278
34.306
35.175
34.280
34.654
35.134
34.223
33.997
34.162
35.038
34.967
average
stdev
± se

118

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment

TABLE 61: Raw data for moisture retention curve of BCTM P sludge
pressure

trial

[bar]
0.1
0.3
0.3
0.3
0.5
0.7
1.0
1.0
2.0
5.0
10.0
15.0
15.0
15.0

#
1
1
2
3
1
1
1
2
1
1
1
1
2
3

alu em pty & sam ple w et

m ass w et & sam ple dry

m ass dry

Db
[g/cm 3]
0.159
0.158
0.159
0.149
0.154
0.156
0.153
0.151
0.153
0.150
0.152
0.151
0.149
0.151
0.153
0.004
0.001

[g]

[g]

[g]

[g]

[g]

3.829
3.829
3.830
3.837
3.830
3.830
3.830
3.840
3.841
3.652
3.650
3.651
3.840
3.651

27.017
24.760
26.152
25.179
23.794
24.605
24.184
23.796
23.822
22.823
23.067
22.638
22.700
23.615

23.188
20.931
22.322
21.342
19.964
20.775
20.354
19.956
19.981
19.171
19.417
18.987
18.860
19.964

9.777
9.745
9.774
9.416
9.578
9.658
9.555
9.488
9.572
9.241
9.333
9.276
9.421
9.299

5.948
5.916
5.944
5.579
5.748
5.828
5.725
5.648
5.731
5.589
5.683
5.625
5.581
5.648
average
stdev
± se

TABLE 62: Raw data for moisture retention curve of blended BCTM P sludge
pressure

trial

[bar]
0.1
0.3
0.3
0.3
0.5
0.7
1.0
1.0
2.0
5.0
10.0
15.0

#
1

15.0
15.0

1
2
3
1
1
1
2
1
1
1
1
2
3

alu em p ty & sam ple w et

m ass w e t & sam ple dry

m ass d ry

Db

[g]

[g]

[g]

[g]

[g]

3.816
3.816
3.817

30.809
25.677
29.486
28.427
27.203
26.684
26.957
26.406
27.354
26.822
27.043
26.645

26.993
21.861
25.669
24.612
23.387
22.866
23.140
22.589
23.536
23.239
23.462
23.065

6.611
6.454
6.870
6.342
6.735
6.529
6.625
6.464
6.606
6.879
6.631
6.783

[g/cm 3]
0.177
0.173
0.184
0.170
0.180
0.175
0.177
0.173
0.177
0.184
0.177
0.182

25.405
26.893

21.588
23.312

10.427
10.270
10.687
10.157
10.551
10.347
10.442
10.281
10.424
10.462
10.212
10.363
10.348
10.134

6.531
6.553
average
stdev
±se

0.175
0.175
0 .177
0.004
0.001

3.815
3.816
3.818
3.817
3.817
3.818
3.583
3.581
3.580
3.817
3.581

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment

TABLE 63: Raw data for moisture retention curve of BCTMP sludge-soil mixture 40:10
pressure

trial

[bar]
0.1
0.3
0.3
0.3

#
1
1
2
3
1
1
1
2
1
1
1
1
2
3

0.5
0.7
1.0
1.0
2.0
5.0
10.0
15.0
15.0
15.0

alu em pty & sam ple w et

m ass w e t & sam ple dry

m ass dry

Db
[g/cm 3]
0.307
0.331
0.308
0.336
0.341
0.337
0.334
0.333
0.324
0.374
0.360
0.348
0.324
0.313
0.334
0.019
0.005

[g]

[g]

[g]

[g]

[g]

3.162
3.158
3.158
3.695
3.159
3.157
3.157
3.155
3.704
3.624

36.213
34.812
35.651
36.308
33.499
33.894
34.046
33.479
32.731
36.822
36.060
35.591
32.547
33.429

33.051
31.654
32.493
32.613
30.340
30.737
30.889
30.324
29.027
33.198
32.434
31.967
28.847
29.805

14.629
15.513
14.650
16.261
15.902
15.751
15.635
15.599
15.808
17.596
17.091
16.623
15.807
15.332

11.467
12.355
11.492
12.566
12.743
12.594
12.478
12.444
12.104
13.972
13.465
12.999
12.107
11.708
average
stdev
± se

3.626
3.624
3.700
3.624

TABLE 64: Raw data for moisture retention curve of BCTM P sludge-soil mixture 30:20
pressure

trial

[bar]
0.1
0.3
0.3
0.3
0.5
0.7
1.0
1.0
2.0
5.0
10.0
15.0
15.0
15.0

#
1
1
2
3
1
1
1
2
1
1
1
1
2
3

alu em pty & sam p le w e t

m ass w et & sam ple dry

m ass dry

Db
[g/cm 3]
0.433

[g]

[g]

[g]

[g]

[g]

3.784
3.797
3.796
3.787
3.794
3.792
3.792
3.792
3.803
3.650
3.652
3.650
3.792
3.651

38.088
36.125
36.530
37.621
36.382
37.351
37.827
37.335
36.717
38.094
37.945
37.436
35.703
35.908

34.304
32.328
32.734
33.834
32.588
33.559
34.035
33.543
32.914
34.444
34.293
33.786
31.911
32.257

19.975
19.873
19.716
19.413
19.904
20.151
21.187
20.888
20.608
21.462
21.255
21.027
20.617
19.312

16.191
16.076
15.920
15.626
16.110
16.359
17.395
17.096
16.805
17.812
17.603
17.377
16.825
15.661
average
stdev
±se

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

0.430
0.426
0.418
0.431
0.438
0.465
0.457
0.450
0.477
0.471
0.465
0.450
0.419
0.445
0.020
0.005

Appendix I: Pressure Plate Experiment

TABLE 65: Raw data for moisture retention curve of BCTMP sludge-soil mixture 25:25
pressure

trial

[bar]
0.1
0.3
0.3
0.3
0.5
0.7

#
1
1
2
3
1
1

1.0
1.0
2.0
5.0
10.0
15.0
15.0

1
2

3.821
3.820

1
1
1
1
2
3

3.821
3.668
3.668
3.668
3.823
3.668

15.0

alu em pty & sam ple w et

m ass w et & sam p le dry

m ass d ry

Db
[g/cm 3]
0.658
0.569
0.543
0.549
0.467
0.470
0.471
0.470
0.477
0.524
0.536
0.495
0.452

[g]

[g]

[g]

[g]

[g]

3.818
3.821
3.822

52.304
42.510
41.830
42.386
34.589
34.772
35.029
35.116
35.219
36.344
36.704
36.224
34.075

48.486
38.689
38.008
38.568
30.761
30.950
31.208
31.296
31.398
32.676
33.036
32.556
30.252
31.352

28.409
25.091
24.130
24.331
21.268
21.392
21.425
21.383
21.652
23.252
23.702
22.153
20.710
21.579

24.591
21.270
20.308
20.513
17.440
17.570
17.604
17.563
17.831
19.584
20.034
18.485
16.887
17.911
average
stdev

3.818
3.828
3.822

35.020

0.479
0.511
0.056

+ se

0.015

TABLE 66: Raw data for moisture retention curve of BC TM P sludge-soil mixture 20:30
pressure

trial

[bar]
0.1
0.3
0.3
0.3
0.5
0.7
1.0
1.0
2.0
5.0
10.0
15.0

#
1
1
2

15.0
15.0

3
1
1
1
2
1
1
1
1
2
3

alu em p ty & sam ple w e t

m ass w e t & sam p le dry

m ass dry

Db
[g/cm 3]
0.504
0.578
0.568
0.559
0.549
0.572
0.558
0.569
0.562
0.620
0.604
0.619
0.542
0.565
0.569
0.031
0.008

[g]

[g]

[g]

[g]

[g]

3.827
3.829
3.830
3.826
3.830
3.829
3.828
3.828
3.830
3.679
3.680
3.679

37.420
39.065
42.759
41.559
36.996
37.907
37.563
38.083
37.859
40.949
40.900
39.950
36.795
39.411

33.593
35.236
38.929

22.644
25.425
25.066
24.716
24.360
25.210
24.669
25.092
24.832
26.863
26.250
26.798
24.071
24.804

18.817
21.596
21.236
20.890
20.530
21.381
20.841
21.264
21.002
23.184
22.570
23.119
20.240
21.125
average
stdev
± se

3.831
3.679

37.733
33.166
34.078
33.735
34.255
34.029
37.27
37.220
36.271
32.964
35.732

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment

TABLE 67: Raw data for moisture retention curve of BCTMP sludge-soil mixture 10:40
pressure

trial

[bar]
0.1
0.3
0.3
0.3
0.5
0.7
1.0
1.0
2.0
5.0
10.0
15.0
15.0
15.0

#
1
1
2
3
1
1
1
2
1
1
1
1
2
3

alu em p ty & sam ple w e t

m ass w e t & sam ple dry

m ass dry

Db
[g/cm 3]
0.982
0.959
0.950
0.954
0.956
0.955
0.965
0.946
0.956
0.960
0.991
0.968
0.986
0.969
0.964
0.014
0.004

[g]

[g]

[g]

[g]

[g]

3.786
3.814
3.816
3.816
3.818
3.824
3.824
3.822
3.822
3.699
3.699
3.698
3.821
3.700

60.560
56.166
58.258
58.645
55.981
54.870

56.774
52.352
54.442
54.829
52.163
51.046

40.473
39.666
39.323
39.455
39.559
39.520

36.687
35.852
35.507

55.863
55.167
55.697
55.094
55.879
54.862
56.023
56.148

52.039
51.345
51.875
51.395
52.180
51.164
52.202
52.448

39.868
39.171
39.538
39.569
40.725
39.854
40.666
39.901

35.639
35.741
35.696
36.044
35.349
35.716
35.870
37.026
36.156
36.845
36.201
average
stdev
± se

122

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment

Part B: Moisture retention curves for sludge-soil mixtures
TABLE 68: W HCg, Db, W HCV, and random errors of original Kraft mill sludge.
p re s s u re

trial

[b ar]

#
1
1
2
3
1
1
1
2
1
1
1
1
2
3

0.1
0.3
0.3
0.3
0.5
0.7
1.0
1.0
2.0
5.0
10.0
15.0
15.0
15.0

m a s s w e t m a s s d ry

[g]

[g]

23.463
20.215
19.256
19.477
18.471
19.404
17.953
16.730
16.996
18.624
18.023
17.248
17.302
17.035

4.751
5.085
4.978
4.917
5.068
5.233
5.043
4.605
4.932
5.307
5.209
4.978
5.229
4.922

WHCg
[%]
394
298
287
296
264
271
256
263
245
251
246
246
231
246

± A WHCg

Db

± A Db

WHCV

± A WHCV

[%]
0.125
0.092
0.091
0.094
0.084
0.083
0.082
0.092
0.081
0.077
0.077
0.081
0.073
0.082

[g /c m 3]

[g /c m 3]

0.127
0.136
0.133
0.132
0.136
0.140
0.135
0.123
0.132
0.142
0.139
0.133
0.140
0.132

0.0026
0.0028
0.0027
0.0027
0.0028
0.0029
0.0028
0.0025
0.0027
0.0029
0.0028
0.0027
0.0029
0.0027

[%]
50
40
38
39
36
38
35
32
32
36
34
33
32
32

[%]
1.022
0.827
0.780
0.796
0.732
0.774
0.705
0.663
0.659
0.728
0.700
0.670
0.660
0.662

TABLE 69: WHCg Db, WHCV, and random errors of blended Kraft mill sludge.
p re s s u re

trial

[bar]

#
1
1
2
3
1
1
1
2
1
1
1
1
2
3

0.1
0.3
0.3
0.3
0.5
0.7
1.0
1.0
2.0
5.0
10.0
15.0
15.0
15.0

m a s s w e t m a s s d ry

[g]

[g]

29.789
23.897
23.233
23.030
21.681
25.983
24.492
21.383
20.036
20.207
24.381
20.539
19.719
20.777

6.347
5.983
6.476
6.160
5.923
7.306
6.880
6.132
5.794
5.642
7.483
6.389
5.763
6.146

WHCg

+ A WHCg

Db

± A Db

WHCV

± A WHCV

[%]
369
299
259
274
266
256
256
249
246
258
226
221
242
238

[%]
0.088
0.078
0.064
0.071
0.072
0.057
0.060
0.066
0.069
0.074
0.050
0.058
0.069
0.064

[g /c m 3]

[g /c m 3]

0.170
0.160
0.173
0.165
0.158
0.196
0.184
0.164
0.155
0.151
0.200
0.171
0.154
0.164

0.0035
0.0033
0.0035
0.0034
0.0032
0.0040
0.0038
0.0034
0.0032
0.0031
0.0041
0.0035
0.0031
0.0034

[%]
63
48
45
45
42
50
47
41
38
39
45
38
37
39

[%]
1.281
0.979
0.916
0.922
0.861
1.020
0.962
0.833
0.778
0.796
0.923
0.773
0.763
0.799

TABLE 70: WHCg , Db, W HCV, and random errors of Kraft mill sludge-soil mixture 40:10.
p re s s u re

tria l

[bar]

#
1
1
2
3

0.1
0.3
0.3
0.3
0.5
0.7
1.0
1.0
2.0
5.0
10.0
15.0
15.0
15.0

1
1
1
2

1
1
1
1
2
3

m a s s w e t m a s s d ry

[g]

[g]

31.178
27.093
24.774
25.814
23.696
25.223
24.968
23.938
22.763
24.642
22.400
22.227
22.446
22.480

9.736
10.098
8.847
10.030
9.126
8.941
10.228
8.887
9.326
9.793
9.733
9.248
10.179
9.806

WHCg
[%]
220
168
180
157
160
182
144
169
144
152
130
140
121
129

i A WHCg

Db

± A Db

WHCV

± A WHCV

[%]
0.038
0.031
0.037
0.030
0.033
0.036
0.028
0.035
0.031
0.030
0.028
0.030
0.026
0.028

[g /c m 3]

[g /c m 3]

0.261
0.270
0.237
0.268
0.244
0.239
0.274
0.238
0.250
0.262
0.260
0.247
0.272
0.262

0.0053
0.0055
0.0048
0.0055
0.0050
0.0049
0.0056
0.0049
0.0051
0.0053
0.0053
0.0051
0.0056
0.0054

[%]
57
45
43
42
39
44
39
40
36
40
34
35
33
34

[%]
1.171
0.928
0.870
0.862
0.796
0.890
0.805
0.822
0.734
0.811
0.692
0.709
0.670
0.692

123

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment
TABLE 71: WHCg, Db, WHCV, and random errors of Kraft mill sludge-soil mixture 30:20.
p re s s u re

tria l

[b ar]

#
1
1
2
3
1
1
1
2
1
1
1
1
2
3

0.1
0.3
0.3
0.3
0.5
0.7
1.0
1.0
2.0
5.0
10.0
15.0
15.0
15.0

m a s s w e t m a s s d ry

[g]

[g]

40.580
33.934
32.504
32.989
31.415
33.467
32.685
31.932
30.262
31.218
30.051
29.704
29.512
29.518

15.233
14.661
15.530
15.474
15.040
15.040
16.224
16.256
16.135
17.503
17.000
15.759
15.616
15.768

WHC„

± A W HC„

Db

± A Db

WHCV

± A W HCV

[%]
166
131
109
113
109
123
101
96
88
78
77
88
89
87

[%]
0.020
0.019
0.016
0.017
0.017
0.018
0.015
0.015
0.015
0.013
0.013
0.015
0.015
0.015

[g /c m 3]

[g /c m 3]

0.408
0.392
0.416
0.414
0.402
0.402
0.434
0.435
0.432
0.468
0.455
0.422
0.418
0.422

0.0083
0.0080
0.0085
0.0085
0.0082
0.0082
0.0089
0.0089
0.0088
0.0096
0.0093
0.0086
0.0085
0.0086

[%]
68
52
45
47
44
49
44
42
38
37
35
37
37
37

[%]
1.385
1.053
0.927
0.957
0.895
1.007
0.899
0.856
0.772
0.749
0.713
0.762
0.759
0.751

TABLE 72: W HCg, Db, W HCV, and random errors of Kraft mill sludge-soil mixture 25:25.
p re s s u re

tria l

[b ar]

#
1
1
2
3
1
1
1
2
1
1
1
1
2
3

0.1
0.3
0.3
0.3
0.5
0.7
1.0
1.0
2.0
5.0
10.0
15.0
15.0
15.0

m a s s w e t m a s s d ry

[g]

[g]

42.872
36.608
37.149
36.854
35.627
32.608
33.673
33.014
32.740
33.737
32.649
31.052
33.473
32.364

19.764
18.642
20.673
18.921
18.793
18.830
18.899
17.498
19.200
19.643
18.926
17.734
19.603
18.817

WHCg
[%]
117
96
80
95
90
73
78
89
71
72
73
75
71
72

1 A WHCg

Db

± A Db

WHCV

± A W HCV

[%]
0.013
0.013
0.011
0.013
0.013
0.012
0.012
0.013
0.012
0.011
0.012
0.013
0.011
0.012

[g /c m 3]

[g /c m 3]

0.529
0.499
0.553
0.506
0.503
0.504
0.506
0.468
0.514
0.526
0.506
0.475
0.525
0.504

0.0108
0.0102
0.0113
0.0103
0.0103
0.0103
0.0103
0.0096
0.0105
0.0107
0.0103
0.0097
0.0107
0.0103

[%]
62
48
44
48
45
37
40
42
36
38
37
36
37
36

[%]
1.262
0.981
0.900
0.980
0.920
0.753
0.807
0.848
0.740
0.770
0.750
0.728
0.758
0.740

TABLE 73: W HCg, Db, W HCV, and random errors of Kraft mill sludge-soil mixture 20:30.
p re s s u re

trial

[bar]

#
1
1
2
3
1
1
1
2
1
1
1
1
2
3

0.1
0.3
0.3
0.3
0.5
0.7
1.0
1.0
2.0
5.0
10.0
15.0
15.0
15.0

m a s s w e t m a s s d ry

[g]

[g]

41.598
39.182
37.543
37.862
36.868
36.187
36.280
35.305
34.248
34.870
34.498
32.756
33.529
33.386

20.913
21.755
22.063
21.470
21.887
22.832
22.041
20.218
22.436
22.602
21.415
21.390
22.154
21.266

WHCg
[%]
99
80
70
76
68
58
65
75
53
54
61
53
51
57

t AWHCg

Db

± A Db

WHCV

± A WHCV

[%]
0.012
0.011
0.010
0.011
0.010
0.009
0.010
0.011
0.010
0.009
0.010
0.010
0.010
0.010

[g /c m 3]

[g /c m 3]

0.560
0.582
0.590
0.575
0.586
0.611
0.590
0.541
0.600
0.605
0.573
0.572
0.593
0.569

0.0114
0.0119
0.0121
0.0117
0.0120
0.0125
0.0120
0.0110
0.0123
0.0123
0.0117
0.0117
0.0121
0.0116

[%]
55
47
41
44
40
36
38
40
32
33
35
30
30
32

[%]
1.130
0.952
0.846
0.896
0.818
0.730
0.778
0.824
0.645
0.670
0.715
0.621
0.621
0.662

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment

TABLE 74: WHCg, Db, WHCV, and random errors of Kraft mill sludge-soil mixture 10:40.
p re s s u re

tria l

[b ar]

#
1
1
2
3
1
1
1
2
1
1
1
1
2
3

0.1
0.3
0.3
0.3
0.5
0.7
1.0
1.0
2.0
5.0
10.0
15.0
15.0
15.0

m a s s w e t m a s s d ry

[g]
55.704
52.010
52.489
52.048
49.106
49.629
49.003
48.444
48.434
47.065
46.194
47.473
48.613
48.047

[g]
34.476
34.292
34.864
34.278
34.306
35.175
34.280
34.654
35.134
34.223
33.997
34.162
35.038
34.967

WHC„

± A WHCg

Db

± A Db

W HCV

± A WHCV

[%]
62
52
51
52
43
41
43
40
38
38
36
39
39
37

[%]
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.006
0.006

[g /c m 3]

[g /c m 3]

0.923
0.918
0.933
0.917
0.918
0.941
0.917
0.927
0.940
0.916
0.910
0.914
0.938
0.936

0.0188
0.0187
0.0190
0.0187
0.0187
0.0192
0.0187
0.0189
0.0192
0.0187
0.0186
0.0187
0.0191
0.0191

[%]
57
47
47
48
40
39
39
37
36
34
33
36
36
35

[%]
1.160
0.968
0.963
0.971
0.809
0.790
0.804
0.753
0.727
0.702
0.666
0.727
0.742
0.715

125

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment
TABLE 75: W H C g, Db, W HCV, and random errors of original BCTMP sludge.
p re s s u re

tria l

[b ar]

#
1
1
2
3
1
1
1
2
1
1
1
1
2
3

0.1
0.3
0.3
0.3
0.5
0.7
1.0
1.0
2.0
5.0
10.0
15.0
15.0
15.0

m a s s w e t m a s s d ry

[g]

[g]

23.188
20.931
22.322
21.342
19.964
20.775
20.354
19.956
19.981
19.171
19.417
18.987
18.860
19.964

5.948
5.916
5.944
5.579
5.748
5.828
5.725
5.648
5.731
5.589
5.683
5.625
5.581
5.648

WHCg
[%]
290
254
276
283
247
256
256
253
249
243
242
238
238
253

+ A WHCg

Db

± A Db

WHCV

± A WHCV

[%]
0.077
0.069
0.074
0.080
0.070
0.071
0.072
0.073
0.071
0.071
0.070
0.070
0.070
0.073

[g /c m 3]

[g /c m 3]

0.159
0.158
0.159
0.149
0.154
0.156
0.153
0.151
0.153
0.150
0.152
0.151
0.149
0.151

0.0032
0.0032
0.0032
0.0030
0.0031
0.0032
0.0031
0.0031
0.0031
0.0031
0.0031
0.0031
0.0030
0.0031

[%]
46
40
44
42
38
40
39
38
38
36
37
36
36
38

[%]
0.942
0.820
0.895
0.861
0.777
0.817
0.799
0.782
0.779
0.742
0.750
0.730
0.726
0.782

TABLE 76: WHCg Db, W HCV, and random errors of blended BCTMP sludge.
p re s s u re

tria l

[bar]

#
1
1
2
3
1
1
1
2
1
1
1
1
2
3

0.1
0.3
0.3
0.3
0.5
0.7
1.0
1.0
2.0
5.0
10.0
15.0
15.0
15.0

m a s s w e t m a s s d ry

[g]

[g]

26.993
21.861
25.669
24.612
23.387
22.866
23.140
22.589
23.536
23.239
23.462
23.065
21.588
23.312

6.611
6.454
6.870
6.342
6.735
6.529
6.625
6.464
6.606
6.879
6.631
6.783
6.531
6.553

WHCg

+ A WHCg

Db

± ADb

WHCV

± A WHCV

[%]
308
239
274
288
247
250
249
249
256
238
254
240
231
256

[%]
0.073
0.061
0.063
0.072
0.060
0.062
0.061
0.063
0.063
0.057
0.062
0.058
0.059
0.063

[g /c m 3]

[g /c m 3]

0.177
0.173
0.184
0.170
0.180
0.175
0.177
0.173
0.177
0.184
0.177
0.182
0.175
0.175

0.0036
0.0035
0.0038
0.0035
0.0037
0.0036
0.0036
0.0035
0.0036
0.0038
0.0036
0.0037
0.0036
0.0036

[%]
55
41
50
49
45
44
44
43
45
44
45
44
40
45

[%]
1.114
0.842
1.027
0.998
0.910
0.893
0.902
0.881
0.925
0.894
0.920
0.890
0.823
0.916

TABLE 77: W HCg, Db, WHCV, and random errors of BCTMP sludge-soil mixture 40:10.
p re s s u re

trial

[b ar]

#
1
1
2
3
1
1
1
2
1
1
1
1
2
3

0.1
0.3
0.3
0.3
0.5
0.7
1.0
1.0
2.0
5.0
10.0
15.0
15.0
15.0

m a s s w e t m a s s d ry

[g]

[g]

33.051
31.654
32.493
32.613
30.340
30.737
30.889
30.324
29.027
33.198
32.434
31.967
28.847
29.805

11.467
12.355
11.492
12.566
12.743
12.594
12.478
12.444
12.104
13.972
13.465
12.999
12.107
11.708

WHCg

+ A WHCg

Db

± A Db

WHCV

± A WHCV

[%]
188
156
183
160
138
144
148
144
140
138
141
146
138
155

[%]
0.029
0.024
0.028
0.024
0.022
0.023
0.023
0.023
0.023
0.020
0.021
0.022
0.023
0.025

[g /c m 3]

[g /c m 3]

0.307
0.331
0.308
0.336
0.341
0.337
0.334
0.333
0.324
0.374
0.360
0.348
0.324
0.313

0.0063
0.0067
0.0063
0.0069
0.0070
0.0069
0.0068
0.0068
0.0066
0.0076
0.0074
0.0071
0.0066
0.0064

[%]
58
52
56
54
47
49
49
48
45
51
51
51
45
48

[%]
1.179
1.054
1.147
1.095
0.961
0.991
1.006
0.977
0.925
1.050
1.036
1.036
0.915
0.989

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment
TABLE 78: WHCg, Db, WHCV, and random errors of BCTMP sludge-soil mixture 30:20.
p re s s u re

trial

[bar]

#
1
1
2
3
1
1
1
2
1
1
1
1
2
3

0.1
0.3
0.3
0.3
0.5
0.7
1.0
1.0
2.0
5.0
10.0
15.0
15.0
15.0

m a s s w e t m a s s d ry

[g]

[g]

34.304
32.328
32.734
33.834
32.588
33.559
34.035
33.543
32.914
34.444
34.293
33.786
31.911
32.257

16.191
16.076
15.920
15.626
16.110
16.359
17.395
17.096
16.805
17.812
17.603
17.377
16.825
15.661

WHCg

+ A WHCg

Db

± A Db

WHCV

+ A WHCV

[%]
112
101
106
117
102
105
96
96
96
93
95
94
90
106

[%]
0.016
0.015
0.016
0.017
0.015
0.015
0.014
0.014
0.014
0.013
0.014
0.014
0.014
0.016

[g /c m 3]

[g /c m 3]

0.433
0.430
0.426
0.418
0.431
0.438
0.465
0.457
0.450
0.477
0.471
0.465
0.450
0.419

0.0088
0.0088
0.0087
0.0085
0.0088
0.0089
0.0095
0.0093
0.0092
0.0097
0.0096
0.0095
0.0092
0.0086

[%]
48
43
45
49
44
46
45
44
43
45
45
44
40
44

[%]
0.990
0.888
0.919
0.995
0.900
0.940
0.909
0.899
0.880
0.909
0.912
0.896
0.824
0.907

TABLE 79: WHCg Db, W HCV, and random errors of BCTMP sludge-soil mixture 25:25.
p re s s u re

trial

[bar]

#
1
1
2
3
1
1
1
2
1
1
1
1
2
3

0.1
0.3
0.3
0.3
0.5
0.7
1.0
1.0
2.0
5.0
10.0
15.0
15.0
15.0

m a s s w e t m a s s d ry

[g]

[g]

48.486
38.689
38.008
38.568
30.761
30.950
31.208
31.296
31.398
32.676
33.036
32.556
30.252
31.352

24.591
21.270
20.308
20.513
17.440
17.570
17.604
17.563
17.831
19.584
20.034
18.485
16.887
17.911

WHCg
[%]
97
82
87
88
76
76
77
78
76
67
65
76
79
75

± A WHCg

Db

± A Db

WHCV

± A WHCV

[%]
0.010
0.011
0.012
0.011
0.013
0.013
0.013
0.013
0.013
0.011
0.011
0.012
0.014
0.013

[g /c m 3]

[g /c m 3]

0.658
0.569
0.543
0.549
0.467
0.470
0.471
0.470
0.477
0.524
0.536
0.495
0.452
0.479

0.0134
0.0116
0.0111
0.0112
0.0095
0.0096
0.0096
0.0096
0.0097
0.0107
0.0109
0.0101
0.0092
0.0098

[%]
64
47
47
48
36
36
36
37
36
35
35
38
36
36

[%]
1.305
0.952
0.967
0.986
0.728
0.731
0.743
0.750
0.741
0.715
0.710
0.769
0.730
0.734

TABLE 80: W H C g, Db, W HCV, and random errors of BCTMP sludge-soil mixture 20:30.
p re s s u re

tria l

[bar]

#
1
1
2
3
1
1
1
2
1
1
1
1
2
3

0.1
0.3
0.3
0.3
0.5
0.7
1.0
1.0
2.0
5.0
10.0
15.0
15.0
15.0

m a s s w e t m a s s d ry

[g]

[g]

33.593
35.236
38.929
37.733
33.166
34.078
33.735
34.255
34.029
37.270
37.220
36.271
32.964
35.732

18.817
21.596
21.236
20.890
20.530
21.381
20.841
21.264
21.002
23.184
22.570
23.119
20.240
21.125

WHCg
[%]
79
63
83
81
62
59
62
61
62
61
65
57
63
69

± A WHCg

Db

± A Db

WHCV

± A WHCV

[%]
0.012
0.010
0.011
0.011
0.011
0.010
0.010
0.010
0.010
0.009
0.010
0.009
0.011
0.011

[g /c m 3]

[g /c m 3]

0.504
0.578
0.568
0.559
0.549
0.572
0.558
0.569
0.562
0.620
0.604
0.619
0.542
0.565

0.0103
0.0118
0.0116
0.0114
0.0112
0.0117
0.0114
0.0116
0.0115
0.0127
0.0123
0.0126
0.0111
0.0115

[%]
40
36
47
45
34
34
35
35
35
38
39
35
34
39

[%]
0.807
0.745
0.967
0.920
0.690
0.694
0.704
0.710
0.712
0.770
0.800
0.719
0.695
0.798

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment

TABLE 81: WHCg, Db, WHCV, and random errors of BCTMP sludge-soil mixture 10:40.
p re s s u re

trial

[bar]

#

m a s s w e t m a s s d ry

[g]

[g]

0.1

1

5 6 .7 7 4

3 6 .6 8 7

W HCn

±A W H C „

Db

± A Db

W HCV

± A W HCV

[%]
55

[%]
0 .0 0 6

[g /c m 3]

[g /c m 3]

0 .9 8 2

0 .0 2 0 0

[% ]
54

[%]
1.097
0.901

0.3

1

5 2 .3 5 2

3 5 .8 5 2

46

0 .0 0 6

0 .9 5 9

0 .0 1 9 6

44

0.3

2

5 4 .4 4 2

3 5 .5 0 7

53

0 .0 0 6

0 .9 5 0

0 .0 1 9 4

51

1.034

0.3

3

5 4 .8 2 9

3 5 .6 3 9

54

0 .0 0 6

0 .9 5 4

0 .0 1 9 5

51

1.048

0.5

1

5 2 .1 6 3

35.741

46

0 .0 0 6

0 .9 5 6

0 .0 1 9 5

44

0.8 9 7

0 .7

1

5 1 .0 4 6

3 5 .6 9 6

43

0 .0 0 6

0 .9 5 5

0 .0 1 9 5

41

0.8 3 9

1.0

1

5 2 .0 3 9

3 6 .0 4 4

44

0 .0 0 6

0 .9 6 5

0 .0 1 9 7

43

0.8 7 4

1.0

2

5 1 .3 4 5

3 5 .3 4 9

45

0 .0 0 6

0 .9 4 6

0 .0 1 9 3

43

0.8 7 4

2.0

1

5 1 .8 7 5

3 5 .7 1 6

45

0.0 0 6

0 .9 5 6

0 .0 1 9 5

43

0.8 8 3

5.0

1

5 1 .3 9 5

3 5 .8 7 0

43

0.0 0 6

0 .9 6 0

0 .0 1 9 6

42

0.8 4 8

10.0

1

5 2 .1 8 0

3 7 .0 2 6

41

0.0 0 6

0.991

0 .0 2 0 2

41

0.8 2 8

15.0

1

5 1 .1 6 4

3 6 .1 5 6

42

0.0 0 6

0 .9 6 8

0 .0 1 9 8

40

0 .8 2 0

15.0

2

5 2 .2 0 2

3 6 .8 4 5

42

0.0 0 6

0 .9 8 6

0.0201

41

0.8 3 9

15.0

3

5 2 .4 4 8

36.201

45

0.0 0 6

0 .9 6 9

0 .0 1 9 8

43

0.8 8 8

128

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment
Moisture retention curves for Kraft mill sludge-soil mixtures

—♦ — original
- X - 40:10
30:20
□

10:40

£ 50

40

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

p r e s s u r e [b a r ] x (-1 )

FIGURE 15: Moisture retention curves for Kraft mill sludge, Kraft mill sludge-soil mixtures 40:10, 30:20 and 10:40
from 0.1 to 15 bar x (-1).

129

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment

80
-□— blend
X - 25:25
•

-2 0 :3 0

70

60

2 50

40

30

20
0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

p r e s s u r e [b a r ] x (-1 )

FIGURE 16: Moisture retention curves for blended Kraft mill sludge, Kraft mill sludge-soil mixtures 25:25 and 20:30
from 0.1 to 15 bar x (-1).

130

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment

■♦

original

—X— 40:10
A

30:20

SI

10:40

40

0.0

2.0

0.5

2.5

pressure [bar] x (-1)
FIGURE 17: Moisture retention curves for Kraft mill sludge, Kraft mill sludge-soil mixtures 40:10, 30:20 and 10:40
from 0.1 to 2.5 bar x (-1).

131

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix i: Pressure Plate Experiment

-□— blend
- X - - 25:25
♦ — 20:30

'""X

-X

40

X

0.0

2.0

0.5

2.5

pressure [bar] x (-1)
FIGURE 18 : Moisture retention curves for blended Kraft mill sludge, Kraft mill sludge-soil mixtures 25:25 and 20:30
from 0.1 to 2.5 bar x (-1).

132

Appendix I: Pressure Plate Experiment
Moisture retention curves for Kraft mill sludge-soil mixtures with random errors

80
♦

original

—x — 40:10
70

A

30:20

□

10:40

60

50

40

30

20
0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

pressure [bar] x (-1)
F IG U R E 19: Moisture retention curves for original Kraft mill sludge, Kraft mill sludge-soil
mixtures 40:10, 30:20 and 10:40 with random errors from 0.1 to 15 b a rx (-1).

— □ — blend
-- X-

25:25

— • — 20:30

40

□--------

X

^ —

30

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

pressure [bar] x (-1)
F IG U R E 20: Moisture retention curves for blended Kraft mill sludge, Kraft mill sludge-soil
mixtures 25:25 and 20:30 with random errors from 0.1 to 15 bar x (-1).

133

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment

—♦ — o rig in a l

- x - 4 0 :1 0
A

3 0 :2 0

H

10:40

40

0.0

2.0

0.5

2 .5

pressure [bar] x (-1)
F IG U R E 2 1 : M o is tu re re te n tio n c u rv e s fo r o rig in a l K ra ft m ill s lu d g e , K ra ft m ill s lu d g e -s o il
m ix tu re s 4 0 :1 0 , 3 0 :2 0 a n d 10:4 0 w ith ra n d o m e rro rs fro m 0.1 to 2 .5 b a r x (-1 ).

— □ — ble n d
- X-

2 5 :2 5

— • — 2 0 :3 0

0.0

2.0

0.5

2 .5

pressure [bar] x (-1)
F IG U R E 22 : M o is tu re re te n tio n c u rv e s fo r b le n d e d K ra ft m ill s lu d g e , K ra ft m ill s lu d g e -s o il
m ix tu re s 2 5 :2 5 a n d 2 0 :3 0 w ith ra n d o m e rro rs fro m 0.1 to 2 .5 b a r x (-1).

134

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment

Moisture retention curves for BCTMP sludge-soil mixtures

original

- - -X - - 25:25
13

10:40

3r
40

>©<

20
0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

pressure [bar] x (-1)
FIGURE 23 : Moisture retention curves for BCTMP sludge, BCTMP sludge-soil mixtures 40:10, 25:25 and 10:40
from 0.1 to 15 bar x (-1).

135

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment

blend
30:20
20:30

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

pressure [bar] x (-1)
FIGURE 2 4 : Moisture retention curves fo r blended BCTMP sludge, BCTMP sludge-soil mixtures 20:30 and 30:20
from 0.1 to 15 bar x (-1).

136

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment

♦ — original

X

25:25

■

10:40

E 50

0.0

2.0

0.5

2.5

pressure [bar] x (-1)
FIGURE 2 5 : Moisture retention curves for BCTMP sludge, BCTMP sludge-soil mixtures 40:10, 25:25 and 10:40
from 0.1 to 2.5 b a rx (-1).

137

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment

80

70

60

40

30

20
0.0

0.5

1.0

1.5

2.0

2.5

pressure [bar] x (-1)
FIGURE 26 : Moisture retention curves for blended BCTMP sludge, BCTMP sludge-soil mixtures 20:30 and 30:20
from 0.1 to 2.5 bar x (-1).

138

Appendix I: Pressure Plate Experiment
Moisture retention curves for BCTMP sludge-soil mixtures with random errors

original
40:10
25:25
10:40
^

60

E 40

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

pressure [bar] x (-1)
F IG U R E 2 7 : Moisture retention curves for BCTM P sludge, BCTM P sludge-soil mixtures
40:10, 25:25 and 10:40 with random errors from 0.1 to 15 b a rx (-1).

30

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

pressure [bar] x (-1)
F IG U R E 28 : Moisture retention curves for blended BCTM P sludge, BCTM P sludge-soil mixtures
30:20 and 20:30 with random errors from 0.1 to 15 bar x (-1).

139

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment

80
—♦ — original
- * — 40:10

0.0

X

25:25

a

10:40

2.0

0.5

2.5

pressure [bar] x (-1)
F IG U R E 29 : Moisture retention curves for BCTM P sludge, B C TM P sludge-soil mixtures
40:10, 25:25 and 10:40 with random errors from 0.1 to 2.5 bar x (-1).

hh—

blend

A

30:20

•--2 0 :3 0

0.0

2.0

0.5

2.5

pressure [bar] x (-1)
F IG U R E 30 : Moisture retention curves for blended BCTM P sludge, BCTM P sludge-soil mixtures
30:20 and 20:30 with random errors from 0.1 to 2.5 bar x (-1).

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment

Part C : Moisture retention curves for sludge-soil layer systems

TABLE 82: Raw data for bulk density, W H C g and W H C V determination of each sludge and soil layer for Kraft mill sludge.

pressure
[bar]
0.5

sample

[g]
1 layer

2 layer

3 layer

1.0

column empty column&sample mass wet

1 layer

2 layer

3 layer

sludge (1/1)
soil (1/1)
sludge (1/1)
soil (1/1)
sludge (1/2)
soil (1/2)
sludge (1/1)
soil (1/1)
sludge (1/2)
soil (1/2)
sludge (1/3)
soil (1/3)
sludge (1/1)
soil (1/1)
sludge (1/1)
soil (1/1)
sludge (1/2)
soil (1/2)
sludge (1/1)
soil (1/1)
sludge (1/2)
soil (1/2)
sludge (1/3)
soil (1/3)

63.636
63.636
63.184
63.184
63.184
63.184
63.956
63.956
63.956
63.956
63.956
63.956
63.670
63.670
63.112
63.112
63.112
63.112
63.760
63.760
63.760
63.760
63.760
63.760

[g]

[g]

105.876
233.100
90.656
138.430
163.370
221.905
80.854
121.990
139.910
179.120
191.845
234.665
106.402
240.765
90.836
145.445
170.240
235.855
81.566
122.045
142.875
182.695
198.170
239.965

42.240
127.224
27.472
47.774
24.940
58.535
16.898
41.136
17.920
39.210
12.725
42.820
42.732
134.363
27.724
54.609
24.795
65.615
17.806
40.479
20.830
39.820
15.475
4 1.795

height
[cm]

volume
[cm3]

mass dry

2.5
3.2
1.5
1.5
1.5
1.5
1.0
1.0
1.0
1.0
1.0
1.0
3.0
3.0
1.5
1.5
1.5
1.5
1.0
1.0
1.0
1.0

93.435
119.596
56.061
56.061
56.061
56.061
37.374
37.374
37.374
37.374
37.374
37.374
112.122
112.122
56.061
56.061
56.061
56.061
37.374
37.374

9.281
93.857
6.028
35.819
5.741
43.036
3.871
30.95998
4.347611
29.17028
3.34202
31.72521
12.39111
101.0059
8.21771
41.82798
7.562232

1.0
1.0

37.374
37.374
37.374
37.374

[g]

49.3774
5.499461
30.79523
6.488033
28.56459
4.805622
31.65859

Db
[g/cm3]
0.099
0.785
0.108
0.639
0.102
0.768
0.104
0.828
0.116
0.780
0.089
0.849
0.111
0.901
0.147
0.746
0.135
0.881
0.147
0.824
0.174
0.764
0.129
0.847

WHCg

WHCV

[%]
355
36
356
33
334
36
337
33
312
34
281
35
245
33
237
31
228
33
224
31
221
40
222
32

[%]
35
28
38
21
34
28
35
27
36
27
25
30
27
30
35
23
31
29
33
26
38
31
29
27

141

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment

pressure
[bar]

sample

5.0

sludge (1/1)
soil (1/1)
sludge (1/1)
soil (1/1)
sludge (1/2)
soil (1/2)
sludge (1/1)
soil (1/1)
sludge (1/2)
soil (1/2)
sludge (1/3)
soil (1/3)

1 layer

2 layer

3 layer

column empty column&sample

mass

[g]

[g]

[g]

height
[cm]

63.504
63.504
63.958
63.958
63.958
63.958
63.934
63.934
63.934
63.934
63.934
63.934

106.128
233.500
91.160
146.480
167.945
236.305
81.026
122.190
140.660
180.260
193.210
235.190

42.624
127.372
27.202
55.320
21.465
68.360
17.092
41.164
18.470
39.600
12.950
41.980

2.9
3.0
1.6
1.5
1.5
1.5
1.0
1.0
1.1
1.0
0.9
1.0

volume
[cm3]

mass dry

[g]

Db
[g/cm3]

108.384
112.122
59.798
56.061
56.061
56.061
37.374
37.374
41.111
37.374
33.636
37.374

14.5458
96.47162
8.942058
41.85136
6.860678
51.64439
6.731907
31.59084
6.914675
30.29019
4.810314
32.34456

0.134
0.860
0.150
0.747
0.122
0.921
0.180
0.845
0.168
0.810
0.143
0.865

WHCg

W HCV

[%]
193
32
204
32
213
32
154
30
167
30
169
30

[%]
26
28
31
24
26
29
28
25
28
24
24
26

142

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment

TABLE 83: Raw data for bulk density, W H C g and W H C V determination of each sludge and soil layer for B C TM P sludge.

pressure
[bar]

sample

0.5

sludge (1/1)
soil (1/1)
sludge (1/1)
soil (1/1)
sludge (1/2)
soil (1/2)
sludge (1/1)
soil (1/1)
sludge (1/2)
soil (1/2)
sludge (1/3)
soil (1/3)
sludge (1/1)
soil (1/1)
sludge (1/1)
soil (1/1)
sludge (1/2)
soil (1/2)
sludge (1/1)
soil (1/1)
sludge (1/2)
soil (1/2)
sludge (1/3)
soil (1/3)

1 layer

2 layer

3 layer

1.0

1 layer

2 layer

3 layer

column empty column&sample mass wet

[g]

[g]

[g]

61.758
61.758
62.266
62.266
62.266
62.266
61.862
61.862
61.862
61.862
61.862
61.862
61.670
61.670
62.184
62.184
62.184
62.184

133.890
260.180
100.600
153.630
194.095
258.420
83.036
123.930
143.200
193.535
215.145
258.200
139.925
245.480
99.570
152.285
188.010
239.860
89.590
130.210
152.750
199.990
220.950
258.185

72.132
126.290
38.334
53.030
40.465
64.325
21.174
40.894
19.270
50.335
21.610
43.055
78.255
105.555
37.386
52.715
35.725
51.850

61.832
61.832
61.832
61.832
61.832
61.832

27.758
40.620
22.540
47.240
20.960
37.235

height
[cm]

volume
[cm3]

mass dry

3.0
3.0
1.5
1.5
1.7
1.5
1.0
1.0
1.0
1.0
1.1
1.0
3.0
3.0
1.5
1.5
1.5
1.5
1.0
1.0
1.0
1.0
1.0
1.0

112.122
112.122
56.061
56.061
63.536
56.061
37.374
37.374
37.374
37.374
41.111
37.374
112.122
112.122
56.061
56.061
56.061
56.061
37.374
37.374
37.374
37.374
37.374
37.374

18.257
92.116
9.951
38.920
10.389
45.888
5.592
29.689
5.277
36.948
5.918
31.228
21.634
78.350
10.607
39.037
10.207
38.540
8.031
29.971
6.560
34.766
6.097

[g]

27.713

Db
[g/cm3]
0.163
0.822
0.178
0.694
0.164
0.819
0.150
0.794
0.141
0.989
0.144
0.836
0.193
0.699
0.189
0.696
0.182
0.687
0.215
0.802
0.176
0.930
0.163
0.742

WHCg

WHCV

[%]
295
37
285
36
289
40
279
38
277
36
266
38
262
35
253
35
250
35
246
36
244
36
244
34

[%]
48
30
51
25
47
33
42
30
39
36
38
32
51
24
48
24
46
24
53
29
43
33
40
25

143

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment

pressure
[bar]

sample

5.0

sludge (1/1)
soil (1/1)
sludge (1/1)
soil (1/1)
sludge (1/2)
soil (1/2)
sludge (1/1)
soil (1/1)
sludge (1/2)
soil (1/2)
sludge (1/3)
soil (1/3)

1 layer

2 layer

3 layer

column empty column&sample mass wet

[g]

[g]

[g]

height
[cm]

64.270
64.270
63.998
63.998
63.998
63.998
64.812
64.812
64.812
64.812
64.812
64.812

136.550
260.810
101.120
154.380
195.040
259.625
86.754
126.575
146.305
196.490
218.715
261.520

72.280
124.260
37.122
53.260
40.660
64.585
21.942
39.821
19.730
50.185
22.225
42.805

3.0
3.0
1.5
1.5
1.5
1.5
1.0
1.0
1.0
1.0
1.0
1.0

volume
[cm3]

mass dry

[g]

Db
[g/cm3]

112.122
112.122
56.061
56.061
56.061
56.061
37.374
37.374
37.374
37.374
37.374
37.374

21.204
92.100
11.542
39.823
11.999
48.718
6.973
29.960
6.272
37.705
6.698
32.323

0.189
0.821
0.206
0.710
0.214
0.869
0.187
0.802
0.168
1.009
0.179
0.865

WHCg

W HCV

[%]
241
35
222
34
239
33
215
33
215
33
221
32

[%]
46
29
46
24
51
29
40
26
36
33
40
28

144

Appendix I: Pressure Plate Experiment

TABLE 84: Determination of bulk density, gravimetric and volumetric moisture content with random
errors of each layer and the total W H C V of the sludge-soil layers for Kraft mill sludge.
pressure

sam ple

[bar]
0.5

sludge (1/1)

1.0

5.0

soil (1/1)
sludge (1/1)
sludge (1/2)
soil (1/1)
soil (1/2)
sludge (1/1)
sludge (1/2)
sludge (1/3)
soil (1/1)
soil (1/2)
soil (1/3)
sludge (1/1)
soil (1/1)
sludge (1/1)
sludge (1/2)
soil (1/1)
soil (1/2)
sludge (1/1)
sludge (1/2)
sludge (1/3)
soil (1/1)
soil (1/2)
soil (1/3)
sludge (1/1)
soil (1/1)
sludge (1/1)
sludge (1/2)
soil (1/1)
soil (1/2)
sludge (1/1)
sludge (1/2)
sludge (1/3)
soil (1/1)
soil (1/2)
soil (1/3)

WHCg

± A WHCg

Db

± A Db

W HCV

[%]
355
36
356
334
33
36
337
312
281
33
34
35
245
33
237
228
31
33
224
221
222
31
40
32
193
32
204
213
32
32
154
167
169
30
31
30

[%]
0.058
0.002
0.090
0.089
0.006
0.005
0.134
0.111
0.133
0.007
0.007
0.006
0.032
0.002
0.047
0.050
0.005
0.004
0.068
0.057
0.077
0.007
0.007
0.006
0.023
0.002
0.039
0.053
0.005
0.004
0.044

[g/cm 3]
0.099
0.785
0.108
0.102
0.639
0.768
0.104
0.116
0.089
0.828
0.780
0.849
0.111
0.901
0.147
0.135
0.746
0.881
0.147
0.174
0.129
0.824

[g/cm 3]

[%]
35
28
38
34
21
28
35
36
25
27
27
30
27
30
35
31
23
29
33
38
29
26
31
27
26
28
31
26
24
29
28
28
24

0.045
0.065
0.006
0.007
0.006

0.764
0.847
0.134
0.860
0.150
0.122
0.747
0.921
0.180
0.168
0.143
0.845
0.810
0.865

0.0008
0.0049
0.0014
0.0014
0.0085
0.0102
0.0021
0.0023
0.0018
0.0166
0.0156
0.0170
0.0007
0.0060
0.0020
0.0018
0.0100
0.0118
0.0029
0.0035
0.0026
0.0165
0.0153
0.0170
0.0009
0.0058
0.0019
0.0016
0.0100
0.0123
0.0036
0.0031
0.0032
0.0169
0.0162
0.0173

25
24
26

± A W H C V total WHCV ± A W H C V
[%]
0.283
0.177
0.511
0.466
0.281
0.369

[%]

[%]

31.76

0.167

30.30

0.208

30.05

0.248

28.40

0.134

29.42

0.199

30.58

0.252

26.72

0.128

26.79

0.181

25.99

0.213

0.699
0.727
0.512
0.547
0.531
0.595
0.181
0.199
0.464
0.414
0.309
0.388
0.660
0.768
0.574
0.511
0.612
0.543
0.179
0.184
0.382
0.351
0.319
0.394
0.555
0.511
0.540
0.508
0.487
0.520

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment

TABLE 85: Determination of bulk density, gravimetric and volumetric moisture content with random
errors of each layer and the total W H C V of the sludge-soil layers for B C TM P sludge.

pressure
[bar]

sample

0.5

sludge (1/1)
soil (1/1)
sludge (1/1)
sludge (1/2)
soil (1/1)
soil (1/2)
sludge (1/1)
sludge (1/2)
sludge (1/3)
soil (1/1)
soil (1/2)
soil (1/3)
sludge (1/1)
soil (1/1)
sludge (1/1)
sludge (1/2)
soil (1/1)

1.0

5.0

soil (1/2)
sludge (1/1)
sludge (1/2)
sludge (1/3)
soil (1/1)
soil (1/2)
soil (1/3)
sludge (1/1)
soil (1/1)
sludge (1/1)
sludge (1/2)
soil (1/1)
soil (1/2)
sludge (1/1)
sludge (1/2)
sludge (1/3)
soil (1/1)
soil (1/2)
soil (1/3)

WHCg

± A WHCg

[%]
295
37
285
289
36
40
279
277
266
38
36
38
262
35
253
250
35
35
246
244
244
36
36
34
241
35
222
239
34
33
215
215
221
33
33
32

[%]
0.025
0.002
0.045
0.044
0.005
0.005
0.079
0.084
0.072
0.007
0.006
0.007
0.019
0.003
0.039
0.040
0.005
0.005
0.050
0.061
0.065
0.007
0.006
0.007
0.019
0.002
0.032
0.033
0.005
0.004
0.052
0.058
0.082
0.007
0.005
0.006

Db
[g/cm3]

± A Db
[g/cm3]

0.163
0.822
0.178
0.164

0.0011
0.0055
0.0024
0.0019

0.694
0.819
0.150
0.141
0.144
0.794
0.989
0.836
0.193
0.699
0.189
0.182
0.696
0.687
0.215
0.176
0.163
0.802
0.930
0.742
0.189
0.821
0.206
0.214

0.0093
0.0109
0.0030
0.0028
0.0026
0.0159
0.0198
0.0167
0.0013
0.0047
0.0025
0.0024
0.0093
0.0092
0.0043
0.0035
0.0033
0.0161
0.0186
0.0148
0.0013
0.0055
0.0027
0.0029

0.710
0.869
0.187
0.168
0.179
0.802

0.0095
0.0116
0.0037
0.0034
0.0036
0.0160
0.0202
0.0173

1.009
0.865

WHCV ± A WHCV total WHCV ± A WHCV
[%]
48
30
51
47

[%]
0.321
0.203
0.675
0.560

25
33
42
39
38
30
36
32
51
24
48
46
24
24
53
43
40
29
33
25
46
29

0.334
0.437
0.836
0.783
0.712
0.604
0.701
0.636
0.338
0.163
0.639
0.610
0.325
0.321
1.058
0.857
0.800
0.578
0.670
0.505
0.305
0.192

46
51
24
29
40
36
40
26
33
28

0.610
0.685
0.322
0.383
0.803
0.722
0.792
0.530
0.666
0.554

[%]

[%]

39.22

0.190

38.90

0.259

36.18

0.292

37.51

0.188

35.45

0.249

37.25

0.313

37.16

0.180

37.42

0.261

34.00

0.280

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

Appendix I: Pressure Plate Experiment
Summary: Volumetric moisture content determination for Kraft mill sludge-soil layers
TABLE 86: Total volumetric moisture content of 1, 2, and 3 Kraft mill sludge-soil layer systems
at 0.5, 1.0, and 5.0 bar pressure with random errors.

5.0 bar
1.0 bar
0.5 bar
WHCV ± A WHCV total WHCV ± A WHCV WHCV ± A WHCV total WHCV ± A WHCV WHCV ± A WHCV total WHCV ± A WHCV
[%]
[%]
[%]
[%]
[%]
[%]
[%]
[%]
[%]
[%]
[%]
[%]

pressure

Kraft mill
1 layer
Kraft mill
2 layers

Kraft mill
3 layers

sludge
soil
sludge 1
sludge 2
soil 1
soil 2
sludge 1
sludge 2
sludge 3
soil 1
soil 2
soil 3

35
28
38
34
21
28
35
36
25
27
27
30

0.283
0.177
0.511
0.466
0.281
0.369
0.699
0.727
0.512
0.547
0.531
0.595

31.8

0.167

30.3

0.208

30.1

0.248

27
30
35
31
23
29
33
38
29
26
31
27

0.181
0.199
0.464
0.414
0.309
0.388
0.660
0.768
0.574
0.511
0.612
0.543

28.4

0.134

29.4

0.199

30.6

0.252

26
28
31
26
24
29
28
28
24
25
24
26

0.179
0.184
0.382
0.351
0.319
0.394
0.555
0.511
0.540
0.508
0.487
0.520

26.7

0.128

26.8

0.181

26.0

0.213

Summary: Volumetric moisture content determination for BCTMP sludge-soil layers
TABLE 87: Total volumetric moisture content of 1, 2, and 3 BCTMP sludge-soil layer systems
at 0.5, 1.0, and 5.0 bar pressure with random errors.

5.0 bar
0.5 bar
1.0 bar
WHCV ± A WHCV total WHCV ± A WHCV WHCV ± A WHCV total WHCV ± A WHCV WHCV ± A WHCV total WHCV ± A WHCV

pressure

BCTMP
1 layer
BCTMP
2 layers

BCTMP
3 layers

sludge
soil
sludge 1
sludge 2
soil 1
soil 2
sludge 1
sludge 2
sludge 3
soil 1
soil 2
soil 3

[%]
48
30
51
47
25
33
42
39
38
30
36
32

[%]
0.321
0.203
0.675
0.560
0.334
0.437
0.836
0.783
0.712
0.604
0.701
0.636

[%]

[%]

39.2

0.190

38.9

0.259

36.2

0.292

[%]
51
24
48
46
24
24
53
43
40
29
33
25

[%]
0.338
0.163
0.639
0.610
0.325
0.321
1.058
0.857
0.800
0.578
0.670
0.505

[%]

[%]

37.5

0.188

35.5

0.249

37.3

0.313

[%]
46
29
46
51
24
29
40
36
40
26
33
28

[%]
0.305
0.192
0.610
0.685
0.322
0.383
0.803
0.722
0.792
0.530
0.666
0.554

[%]

[%]

37.2

0.180

37.4

0.261

34.0

0.282

147