s>EPA
United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
tf 0H 45268
EPA-600/2-79-109
May 1979
r~->- *°
) (J ~-
Research and Development
Background
Study on the
Development of a
Standard Leaching
Test
\ /
AUG
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further deveJopment and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and "a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution-sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-79-109
May 1979
BACKGROUND STUDY ON THE DEVELOPMENT OF A
STANDARD LEACHING TEST
by .
Robert Ham
Marc A. Anderson
Rainer Stegmann
Robert Stanforth
Civil and Environmental Engineering Department
University of Wisconsin-Madison
Madison, Wisconsin 53706
Grant No. R-804773
Project Officer
M. Gruenfeld
Oil and Hazardous Materials Spills Branch
Industrial Environmental Research Laboratory-Cincinnati
Edison, New Jersey 08817
-' *
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DISCLAIMER
This report has been reviewed by the Industrial Environmental Research
Laboratory, and the Office of Solid Waste Management Programs9 U. So Environ-
mental Protection Agency, and approved for publication. Approval does not
signify that the contents necessarily reflect the views and policies of the
U. S, Environmental Protection Agency, nor does the mention of trade names or
commercial products constitute endorsement or recommendation for use.
U,s.
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FOREWORD
When energy and material resources are extracted/ processed, converted
and used, the related pollutional impacts on our environment and even on our
health often require that new and increasingly more efficient pollution control
methods be used. The Industrial Environmental Research Laboratory-Cincinnati
(lERL-Ci) assists in developing and demonstrating new and improved method-
ologies that will meet these needs both efficiently and economically.
The Office of Solid Waste has as its major goals, the improvement of
solid waste management in order to protect public health and the environment,
and the conservation of valuable material and energy resources. These objec-
tives include, regulation of the management of hazardous wastes from the point
of generation through disposal, regulation'of the disposal on land of all
other solid wastes, and establishment of resource recovery and conservation
as the preferred solid waste management approach.
The research described in this report is a product of the efforts of the
Industrial Environmental Research Laboratory-Cincinnati (lERL-Ci) and the
Office of Solid Waste. The report deals with a study to develop a leaching
test that can be used widely to assess the leaching characteristics of
industrial wastes. The test procedure provides information regarding some
materials that are likely to be leached from a waste, estimated release
concentrations of these materials, and levels of release per unit weight of
waste. The report suggests several criteria for discriminating between wastes
that produce hazardous leachates and those that do not. It thereby provides
data for decision makers of both government and industry alike contemplating
residue leachate control from industrial sludge impoundment/municipal landfill
co-disposal operations. Information on this subject beyond that supplied in
the report may be obtained from the Hazardous Waste Management .Division of
the Office of Solid Waste, Washington, D. C. 20460 and the Oil and Hazardous
Materials Spills Branch (lERL-Ci), Edison, New Jersey 08817.
David G. Stephan Steffen W. Plehn
Director Deputy Assistant Administrator
Industrial Environmental Research Office of Solid Waste
Laboratory-Cincinnati
**>
111
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ABSTRACT
The principal objective of the research summarized in this report
was to develop a leaching test which could be used widely to assess
the leaching characteristics of industrial wastes. Detailed investi-
gations were made regarding the best general type of test, and the test
variables and operating conditions which must be standardized if the
test is to be used by many laboratories and on different wastes.
The recommended procedure is a batch or flask test, using distilled
water plus other leaching media according to the characteristics of the
landfill(s) of concern. One leaching medium simulates the leaching
characteristics of leachate derived .from actively decomposing municipal
refuse landfills, for example. Test procedures were designed to pro-
vide information regarding the materials likely to be leached from a
waste, an estimate of the maximum concentrations of these materials, an
estimate of the amount of material likely to be released per unit weight
of waste, and an indication of the effect of co-disposal of the waste in
question with mixed municipal refuse or other specific wastes.
This report was submitted in partial fulfillment of Grant No.
R-804773010 by the University of Wisconsin under the sponsorship of
the U.S. Environmental Protection Agency. This report covers the
period July 1, 1976 to January 30, 1978, and work was completed May 26,
1978.
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CONTENTS
Foreword ........ . ..... iii
Abstract iv
Figures ....... ....... viii
Appendix Figures ...... ............ xii
Tables ... ..... ..... xxi
Abbreviations and Symbols xxiii
Acknowledqment ..... xxiv
1. Introduction . 1
2. Conclusions 2
3. Recommendations .............. 4
4. Basic concepts 5
Intensive vs. quick tests ... 5
Ideal and practical leaching tests 5
Batch and column tests 7
Factors in a batch test 7
A. Leachate composition 9
B. Solid to liquid ratio 10
C. Time per elution 11
D. Number of elutions 13
E. Temperature 14
F. Agitation technique . 14
G. Surface area contact between
waste and leachate 14
Summary of existing tests 15
Concluding statement . 15
5. Sample preparation and solid-liquid
separation 17
Overview of leaching test procedure
and wastes tested 17
Sample preparation ............ is
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CONTENTS (continued)
A. Representative sampling ........... 19
B. Particle size reduction ........... 19
C. Leaching media absorption
by wastes .................. '23
D. Homogenization ............... 23
Eo Determination of dry weight .......... 23
Solid-liquid separation ............... 27
Investigations and determination of
test conditions ................... 33
Leaching media composition ........... 33
A. Selection of leaching media ....... 33
B. Development of a synthetic
municipal landfill leachate ....... 35
(1) Aggressive parameters
considered 36
(2) Theoretical degradation
of a landfill 36
(3) Actual degradation of a
landfill ...... 38
(4) Maximum measured con-
centrations of the
parameters and model
compound selection 40
—pH .............. 40
—complexation ......... 42
—redox potential ....... 44
—organic solvents ....... 47
—ionic strength ........ 48
(5) Limitations of the
synthetic leachate ....... 52
(6) A non-anaerobic modi-
fied synthetic leachate .... 52
(7) Concluding statement 53
Solid-liquid ratio . ......... 53
A. General considerations ......... 53
B. Experimental results and
discussion .......... 54
vi
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CONTENTS (concluded)
Agitation methods .... 80
Influence of time per elution . 87
Influence of number of elutions .... 90
Influence of temperature and biological
aspects 101
7. Suggested procedure for a standard leaching
test . . • 108
The leaching test procedure 110
Presentation of the results
from the standard leaching
test ...................... 115
A. Example of presentation and
discussion of results from
a standard leaching test 118
Interpretation of leaching test
results 123
References 129
Appendices 131
vii
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FIGURES
Number Page
1 Types of release in long term leaching test
mentioned by Lee and Plumb with examples from
their leaching experiment using taconite
tailings ......................... 12
2 Differences in conductivity and pH in leachate
from two fly ash particle size fractions ........... 20
3 Differences in iron in leachate from two fly
ash particle size fractions .using a variety
of agitation techniques .'................ 21
4 Effect of cubic particle size on surface area „
per unit volume particles ........ ..... . . .
5 Long term drying characteristics of health and
beauty care waste ........ ............
6 Long term drying characteristics of paint and
ink waste . . .............. ..
7 Long term drying characteristics of water layer
from an oil -water tank with various amounts of
water added .......... ..... ...
8 Movement of moisture from waste in a landfill ....... 28
30
9 Solid-liquid separation scheme ......
10 Comparison of the "dissolved" iron concentrations
in municipal refuse leachate after filtration ..
through various pore sizes ................
11 Theoretical degradation curves of a theoretical
landfill . J/
12 The trends in th.e identified fractions; of
leachate TOC versus the age of the landfill ....... 39
13 Changes in the redox potential of leachate
during storage and after filtration ........... 45
14 Change in synthetic leachate redox potential
with pH ................ ... 46
15 Landfill situations modelled in series V,
procedures 1 and 5 • 55
16 A diagram of test series V
56
viii
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FIGURES (continued)
Number
17 pH and redox results from series V using
paint waste .............. ......... 59
18 COD results from series V using paint waste
19 Specific conductance results from series V
using paint waste .................. • • 61
20 Summary of results from series V: COD . ........ 65
21 Summary of results from series V: K .......... g6
22 Summary of results from series V: Fe .......... 57
23 Summary of results from series V: Zn .......... 68
24 Summary of results from series V: Mg .......... 69
25 Summary of results from series V: Cu .......... 70
26 Effect of solid-liquid ratio on three-
day Fe, K, and COD release ......... ...... 73
27 Effect of solid-liquid ratio on three-
day Zn, Ma, and Mg- release . . ............. 74
28 pH, Mg, Na, Fe concentrations for differ-
ent elutions when fly ash is leached with
0.1N H2 S04, series R2 ........ . ........ 75
29 K, Pb, Cu, and Zn concentrations for differ-
ent elutions when fly ash is leached with
0.1N H2S04, series R2 .................. 77
30 Zinc concentration from paint waste leached
with synthetic leachate in Series Rl for
different elutions and at different solid-
liquid ratios ......... . ............ 73
31 Zn concentration from paint waste leached
with synthetic leachate in series Rl for
more elutions at a 1:10 solid-liquid
ratio (duplicate runs) ..... ............ 79
32 Series R2, maximum concentration after
three days for paint waste and fly ash
at various solid-liquid ratios ............. 31
33 The Ca and Mg results from series PV
using papermill sludge (N) and differ-
ent agitation techniques ................ 83
ix
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FIGURES (continued)
Number Page
34 The Ca and Mg results from series PV using
municipal refuse and different agitation
techniques ......................... 84
35 Diagram of the swing shaker and the rotating
disc device used in series PV ....... „ . . .. . . . . 85
36 Cumulative release after three elutions for
Series PI (COD, Na, K) for different reaction
times ..... .....''....„.......„.... 88
37 Cumulative release after three elutions for
series PI (Mg, Fe, Zn) for different reaction
times ...... ..................... 89
38 Fe concentrations from long term leaching
experiments in series Rl with fly ash and
0.1N H2S04 at various solid-liquid ratios . ........ 92
39 Fe concentrations from long term leaching
experiments in series Rl with fly ash at
solid-liquid ratio of 1:10 (long term
results, duplicate runs) ...... ...... ..... 93
40 Zn concentrations from long term leaching
experiments in series Rl with fly ash and
0.1N H^SO^ at various solid-liquid ratios ......... 94
41 Zn concentrations from long term leaching
experiments in series Rl with fly ash at
solid-liquid ratio of 1:10 (long term re-
sults, duplicate runs) .................. 95
42 Conceptual basis for calcualtion of the
percentage of cumulative release for each
elution in Figures 43 and 44S and Table 19,
as indicated by (1) stable concentration
levels attained or (2) no stable values
attained before the test was terminated .......... 96
43 Cumulative release as a percentage of the
basic or steady state concentration for
various parameters leached from paint
waste and fly ash in series Rl . . ..... . ..... .97
44 Cumulative release as a percentage of the
basic or steady stage concentration for
various parameters leached from paint waste
and fly ash in series Rl (continued) . ..... ..... 98
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FIGURES (concluded)
Number Page
45 A diagram of the toxicity test apparatus 103
46 The volume of methane produced versus time
by a municipal refuse-sewage sludge slurry ........ 104
47 Cumulative releases of several parameters
for municipal refuse leached with distilled
water containing bacterial inhibiting agents,
series B2 106
48 Maximum concentrations of several parameters
for municipal refuse leached with, distilled
water containing bacterial inhibiting agents,
series 83 and B4 ............. 107
49 Waste handling process ........ 109
50 The recommended standard leaching test flow
scheme . H2
51 Suggested presentation of leach test results
for species X from a waste . 116
52 pH and redox from copper oxide-sodium sulfate
sludge 119
53 K concentration and release from copper oxide-
sodium sulfate sludge 120
54 Cu concentration and release from copper oxide-
sodium sulfate sludge 121
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APPENDIX FIGURES
Number Page
A-1 Correction of the moisture content when using the
synthetic leachate .......... ........ 131
A-2 ' Test 82 on the effects of various biologically
inhibiting agents on leaching of municipal wastes.
(See text for procedure.) Redox and pH ........ 132
A-3 Test 82 on the effects of various biologically
inhibiting agents on Leaching of municipal wastes.
Specific conductance ... ........ ...... 133
A-4 Test B2 on the effects of various biologically
inhibiting agents on leaching of municipal wastes.
COD, Mg, and Fe ................... 134
A=5 Test B2 on the effects of various biologically
inhibiting agents on leaching of municipal wastes.
Zn, Pb, K, Cu .................... 135
A-6 Test 84 on the effects of various biologically
inhibiting agents on leaching of municipal wastes.
(See text for procedure.) Redox and pH ....... 136
A-7 Test 84 on the effects of various biologically
inhibiting agents on leaching of municipal wastes.
Specific conductance .......... ....... 137
A-8 Test 84 on the effects of various biologically
inhibiting agents on leaching of municipal wastes.
Na, K, Cus Cd .................... 138
A-9 Test 84 on the effects of various biologically
inhibiting agents on leaching of municipal wastes.
Fe, Mg, Zn, COD ...... . ...... . . ..... 139
A-10 Comparison of tests 82, 83, and 84. (See text
for procedure.) COD, K, Mg ............. 140
A-ll Comparison of tests 82, 83, and 84. (See text
for procedure.) Fe, Zn ............... 141
A-1 2 Test PI on the effect of time per elution using
procedure R on fly ash with distilled water. (See
text for procedure.) pH, Redox, Na, K ........ 142
A-1 3 Test PI with fly ash and distilled water (Mg and
COD) and synthetic leachate (Mg) ........ ... H3
xn
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, APPENDIX FIGURES (continued)
Number Page
A-14 Test PI with fly ash and synthetic leachate.
pHs Redox, Zn, and K . . . 144
A-15 Test PI with fly ash and 0.1N H.SO,.
pH, Redoxs Na, K ........ 7 145
A-16 Test PI with fly ash and 0.1N H7SOd.
Cu, Fe, Mg, COD 7 146
A-17 Test PI on the effect of'time per elution using
procedure R on paint waste with distilled water.
pH, Redoxs Na, K . . . 147
A-18 Test PI with paint waste and distilled water
(Zn, COD, Mg) and synthetic leachate (Mg) 148
A-19 Test PI with paint waste and synthetic
leachate. pH, Redox, Zn, and K 149
A-20 Test PI with paint waste and 0.1N H,SO..
pH, Redox, Na, K . . f 150
A-21 Test PI with paint waste and 0.1N HUSO..
Zn, COD, Mg, Fe 151
A-22 Test PV1 using different agitation techniques
on fly ash with distilled water. (See text
for procedure.) K 152
A-23 Test PV1 using different agitation techniques
on fly ash with distilled water. COD 153
A-24 Test PV2 using different agitation techniques
on papermill sludge with distilled water. (See
text for procedure.) Redox, pH 154
A-25 Test PV2 using different agitation techniques
on papermill sludge with distilled water.
Specific conductance 155
A-26 Test PV2 using different agitation techniques
on papermi11 sludge with distilled water.
K, COD 156
A-27 Test PV3 using different agitation techniques
on shredded municipal refuse with distilled
water. (See text for procedure.) Redox, pH 157
A-28 Test PV3 using different agitation techniques
on shredded municipal refuse with distilled
water. Specific conductance 158
xiii
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APPENDIX FIGURES (continued)
Number - page
A-29 Test PV3 using different agitation techniques
on shredded municipal refuse with distilled
water. Fe, K . . „ . „ . ......... . . . . „ , 159
A-30 Test PV 3 using different agitation techniques
on shredded municipal refuse with distilled
water. K (repeat), Mn ................ 160
A-31 Test PV3 using different agitation techniques
on shredded municipal refuse with distilled
water. Zn ...................... 161
A-32 Test PV3 using different agitation techniques
on shredded municipal refuse with distilled
water. BOD ............ . . 152
A-33 Test PV3 using different agitation techniques
on shredded municipal refuse with distilled
water. COD . 153
A-34 Test PV3 using different agitation techniques
on shredded municipal refuse with distilled
water. Comparison of BOD and COD concentra-
tions .......................... 164
A-35 Test PV4 comparing different agitation techniques
on four wastes with distilled water. (See text
for procedure.) pH and Redox 165
A=36 Test PV4 comparing different agitation tech-
niques on four wastes with distilled water.
Specific conductance .................. 166
A-37 Test PV4 comparing different agitation tech-
niques on four wastes with distilled water. Na .... 167
A-38 Test PV4 comparing different agitation tech-
niques on four wastes with distilled water.
Cu, Zn, Fe ................. 168
A-39 Test PV4 comparing different agitation tech-
niques on four wastes with distilled water.
COD, K. Mg ................ 169
A-40 Test PV4 comparing different agitation tech-
niques on four wastes with distilled water.
COD, Mg, K 170
A-41 Test PV4 comparing the cumulative release of
all measured parameters after 3 elutions
using the rotating disc and intermittent
shaking agitation techniques .............. 171
xiv
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APPENDIX FIGURES (continued)
Number * Page
A-42 Test PV5 comparing different agitation tech-
niques on several wastes with 0.1 N HgSO^.
(See text for procedure.) pH ....... ...... 172
A-43 Test PV5 comparing different agitation techniques
on several wastes with 0.1N H2S04- Redox ....... 173
A-44 Test PV5 comparing different agitation techniques
on several wastes with 0.1N H2S04- Specific
conductance - 174
A-45 Test PV5 comparing different agitation techniques
on several wastes with 0.1N H2S04> Na ........ 175
A-46 Test PV5 comparing different agitation techniques
on several wastes with 0.1N H2S04. COD 176
A-47 Test PV5 comparing different agitation techniques
on several wastes with 0.1N H2S04- K 177
A-48 Test PV5 comparing different agitation techniques
on several wastes with 0.1N H2S04- Mg 178
A-49 Test PV5 comparing different agitation techniques
on several wastes with 0.1N H2S04. Fe 179
A-50 Test PV5 comparing different agitation techniques
with 0.1N H2S04- Cu and Zn . 180
A-51 Test PV5 comparing different agitation techniques
on several wastes with 0.1N H2S04> Pb and Cd 181
A-52 Test PV5 comparing the cumulative release of
all measured parameters after 3 elutions using the
rotating disc and intermittent shaking agitation
techniques ....... ... 182
A-53 Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with fly
ash and synthetic leachate and 0.1N H2S04« pH .... 183
A-54 Expansion of Figure A-53 for a solid-liquid ratio
of 1:10 over more elutions. Duplicate runs 184
A-55 Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with fly
ash and synthetic leachate and 0.1N H-SO,.
Redox ..?....... 185
A-56 Expansion of Figure A-55 for a solid-liquid
ratio of 1:10 over more elutions. Duplicate
runs 186
xv
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APPENDIX FIGURES (continued)
Number Page
A-57 Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with fly
ash and 0.1N H2S04. Na ................ 187
A-58 Expansion of Figure A-57 for a solid-liquid ratio
of 1:10 over more elutions. Duplicate runs ....... 188
A-59 Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with fly
ash and 0.1N H2S04. K -.:................. .,-.- 189
A-60 Expansion of Figure A-59 for a solid-liquid ratio
of 1:10 over more elutions. Duplicate runs ....... 190
A-61 Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with fly
ash and 0.1N HS0. Mg . ...... .....'.... 191
A-62 Expansion of Figure A-61 for a solid-liquid ratio
of 1:10 over more elutions. Duplicate runs ...... 192
A-63 Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with fly
ash and 0.1N HgSO^ Cu ................ 193
A-64 Expansion of Figure A-63 for a solid-liquid ratio
of 1:10 over more elutions. Duplicate runs ...... 194
A-65 Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with fly
ash and 0.1N H2S04. COD ............... 195
A-66 Expansion of Figure A-65 for a solid-liquid ratio
of 1:10 over more elutions. Duplicate runs 196
A-.67 Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with fly
ash and synthetic leachate. K ....... 197
A-68 Expansion of Figure A-67 for a solid-liquid ratio
of 1:10 over more elutions. Duplicate runs ...... 198
A-69 Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with fly
ash and synthetic leachate. Mg ............ 199
A-70 Expansion of Figure A-69 for a solid-liquid ratio
of 1:10 over more elutions. Duplicate runs 200
xvi
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APPENDIX FIGURES (continued)
Number
A-71 Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with fly
ash and synthetic leachate. Zn • • • 201
A-72 Expansion of Figure A-71 for a solid-liquid ratio
of 1:10 over more elutions. Duplicate runs 202
A-73 Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with
paint waste and synthetic leachate and
0.1N H2S04. pH • • • 203
A-74 Expansion of Figure A-73 for a solid-liquid ratio
of 1:10 over more elutions. Duplicate runs . . 204
A-75 Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with
paint waste and synthetic leachate and
0.1N HS0. Redox • •
A-76 Expansion of Figure A-75 for a solid-liquid ratio
of 1:10 over more elutions. Duplicate runs . . .
A-77 Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with
paint waste and 0.1N H2S04- Na .........
A-78 Expansion of Figure A-77 for a solid-liquid ratio
of 1:10 over more elutions. Duplicate runs . . .
A-79 Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with
paint waste and 0.1N H2S04- K
A-80 Expansion of Figure A-79 for a solid-liquid ratio
of 1:10 over more elutions. Duplicate runs . . .
A-81 Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with
paint waste and 0.1N H2S04. Mg *' '
A-82 Expansion of Figure A-81 for a solid-liquid ratio
of 1:10 over more elutions. Duplicate runs L\
-------
APPENDIX FIGURES (continued)
Number Paqe
~""~' ~ " ""--•>• Till I g--| I -|?JL_L J
A-85 Test R1 using procedure R to evaluate different
solid-liquid ratios over five elutions with
paint waste and 0.1N HLSO.. Zn . . . . . „ . . „ . . . . 215
c,
A-86 Expansion of Figure A-85 for a solid-liquid ratio
of 1:10 over more elutions. Duplicate runs ....... 216
A-87 Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with
paint waste and 0.1N H2S04. COD ............ 217
A-88 Expansion of Figure A-87 for a solid-liquid ratio
of 1:10 over more elutions. Duplicate runs ....... 218
A-89 Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with
paint waste and synthetic leachate. K ......... 219
A-90 Expansion of Figure A-89 for a solid-liquid ratio of
1:10 over more elutions. Duplicate runs ... 220
A-91 Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with
paint waste and synthetic leachate. Mg .......... 221
A-92 Expansion of Figure A-91 for a solid-liquid ratio
of 1:10 over more elutions. Duplicate runs . . 222
A»93 Test R2 using procedure C to evaluate different
solid-liquid ratios over five elutions with
paint waste and synthetic leachate. pH, K,
Redox, Pb . . ................. 223
A-94 Test R2 using procedure C to evaluate different
solid-liquid ratios over five elutions with
paint waste and fly ash using synthetic leach-
ate. Mg, Zn, pH, K, Cu ................. 224
A-9S Test R2 using procedure C to evaluate different
solid-liquid ratios over five elutions with
paint waste and 0.1N HgSO^. pH, Fe, Redox, K ...... 225
A-96 Test VI evaluating different contact procedures
with fly ash (EPA) and distilled water. (See
text for procedure.) Specific conductance and
pH .......... .......... 226
A-97 Test VI evaluating different contact procedures
with fly ash (EPA) and distilled water. K and
COD . ... 227
xvm
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APPENDIX FIGURES (continued)
Number
A-98 Test V2 evaluating different contact procedures with
papermin sludge (N) and distilled water. (See text
for procedure.) pH . 228
A-99 Test V2 evaluating different contact procedures with
papermill sludge (N) and distilled water. Specific
conductance 229
A-100 Test V2 evaluating different contact procedures with
papermin sludge (N) and distilled water. Fe 230
A-101 Test V2 evaluating different contact procedures with
papermill sludge (N) and distilled water. K ...... 231
A-102 Test V2 evaluating different contact procedures with
papermill sludge (N) and distilled water. Ca 232
A-103 Test V2 evaluating different contact procedures with
papermill sludge (N) and distilled water. Mg 233
A-104 Test V2 evaluating different contact procedures with
papermill sludge (N) and distilled water. COD 234
A-105 Test V3 evaluating different contact procedures with
paint waste and distilled water. (See text for
procedure.) Zn 235
A-106 Test V4 evaluating different contact procedures with
fly ash and distilled water. (See text for
procedure.) pH and Redox 236
A-107 Test V4 evaluating different contact procedures with
fly ash and distilled water. Specific conductance ... 237
A-108 Test V4 evaluating different contact procedures with
fly ash and distilled water. K . 238
A-109 Test V4 evaluating different contact procedures with
fly ash and distilled water. COD 239
A-110 Test V5 evaluating different contact procedures with
shredded municipal solid waste and distilled water.
(See text for procedure). pH and Redox 240
A-lll Test V5 evaluating difference contact procedures with
shredded municipal solid waste and distilled water.
Specific conductance 241
xix
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APPENDIX FIGURES (concluded)
Number Page
A-112 Test V5 evaluating different contact procedures with
shredded municipal solid waste and distilled water.
K ................ . . . . . . . . . . . . 242
A-113 Test V5 evaluating different contact procedures with
shredded municipal solid waste and distilled water.
Fe ........................... 243
A-114 Test VS evaluating different contact procedures with
shredded municipal solid-waste and distilled water.
Mg ...•.-..'.„....„.... 244
A-115 Test V5 evaluating different contact procedures with
shredded municipal solid waste and distilled water.
A-116 Test VS evaluating different contact procedures with
shredded municipal solid waste and distilled water.
Zn ............................ 246
A-117 Test V5 evaluating different contact procedures with
shredded municipal solid waste and distilled water.
Ca ............................. 247
A-118 Test V5 evaluating different contact procedures with
shredded municipal solid waste and distilled water.
COD ........................... 248
xx
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TABLES
Number Page
1 Factors affecting parameter concentrations
in a batch test ................ 8
2 Classifications of landfills as related to
leachate composition ...... 8
3 Summary of existing leaching test variables . 16
4 A list of several particle separation tech-
niques ' 28
5 Leaching solution for various types of land-
fills ................. 34
6 pH ranges reported by various authors from
landfill or literature surveys 40
7 Minimum pH values found in leachate studies . 41
8 Volatile acid concentrations found in
leachate 41
9 Calculated carbon concentrations of
aromatic hydroxyl compounds found in
leachate .................. 42
10 Organic nitrogen concentrations found
in leachate • • 43
11 Organic compounds or classes identified
in landfill leachate 47
12 Concentrations of the common inorganic
ions found in leachate 49
13 Charge balance calculations for leach-
ate data given by Chian et al (10) ........... 50
14 Directions for preparing the synthetic
leachate ......... 51
15 Maximum concentrations and release 62
16 Statistical results for test series V
for solid-liquid ratio of 1:7 (wet
weight) after one day 71
17 Solid-liquid ratios during test series
R2 75
xxi
-------
TABLES (concluded)
Number
18 Solid-liquid ratios in subsequent elutions
for Procedure C ..............
19 Comparison of the cumulative release when
stable levels are reached to the cumulative
release after a test period of 11 weeks (28
elutions} in percent .................. 99
20 Calculation of the release after 28 elutions
(11 weeks) as a percentage 'of the amount
obtained by total digestion of fly ash ........ 100
21 Leaching media selection according to
landfill conditions .................. 113
22 Calculation of cumulative release for
procedures C and R .................. 117
23 Percentage release results for paper-
mill sludge 118
24 Maximum concentrations after three
elutions of soil, municipal refuse,
and sewage sludge, in mg/1, Procedure C ......... 125
25 Cumulative release after three elutions
of soils municipal refuse, and sewage
sludge in mg/kg dry waste, Procedure R ........ 126
xx 11
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ABBREVIATIONS AND SYMBOLS
A. List of experimental test series and
principal objectives of each
Series B—Biological effects
Series P—Elution time
Series PV—Agitation methods
Series R-Sol1d-liqu1d ratios: $I
Series V—Different landfill situations and solid-liquid ratios
B. List of wastes and designations' used
(see more complete list with sources in Chapter 5)
K Shredded municipal refuse, City of Madison
2. Fly ash (unspecified further), power plant in Wisconsin
3. Paper-mill sludge (N or unspecified further), papermill in
Wisconsin
4. Paint waste (AA), automobile assembly plant
5. Clarifier sludge (AA), automobile assembly plant
6. Fly ash (AA), automobile assembly plant
7. Fly ash (EPA), provided by EPA
8. Papermill sludge (EPA), provided by EPA
9. CuO-Na2S04 slurry, provided by EPA
10. Wastewater treatment sludge, provided by EPA
11. Health and beauty care waste, provided by EPA
(used in Figure 5 only, for this report)
12. Paint and ink waste, provided by EPA (used in Figure 6
only, for this report)
13. Oil/water waste, provided by EPA (used in Figure 7 only,
for this report)
C. Other abbreviations
i
S.L. s Synthetic leachate modeled on municipal refuse landfill leachate
S.L.T. = Standard leaching test (i.e., of specified procedure)
0 = particle size as determined by sieving, mm.
xxm
-------
ACKNOWLEDGMENT
This work was supported by the U. S. Environmental Protection Agency,
Office of Solid Waste Management Programs, under Grant Number R-804773-01-C
Mr. Michael Gruenfeld of the EPA Edison, New Jersey laboratories was the
Project Officer. The authors wish to acknowledge the excellent working
relationship with Messrs. A. Corson, D. Viviani, and D. Sanning of the EPA
who worked closely with project personnel, and especiallys the help and
support of Mr. Gruenfeld.
xxiv
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SECTION 1
INTRODUCTION
Recently an increased awareness of the potential for ground water
pollution from industrial wastes disposed in landfills has become
evident. Since many wastes will not produce polluting leachates when
landfilled, there is need for criteria to discriminate between wastes
that will produce hazardous leachates and those that will not. One
such criterion is a short standardized leaching test which subjects
the waste in the laboratory to simulated landfill conditions or to
test conditions that can be related to landfill conditions. The test
would evaluate the leaching potential of the waste under landfill con-
ditions by indicating what constituents would leach out of the waste,
how much of that material would leach out and under what conditions
they will leach. This report summarizes a background study performed
to develop such a leaching test.
-------
SECTION 2
CONCLUSIONS
Subject to the scope and limitations of this study, the following
conclusions have been reached.
1= Column tests are too time consuming and difficult to perform
for a routine, widely used leaching test. A flask or batch
test is preferred.
2. Solid-liquid separation is necessary prior to a leaching test
in order to handle readi-ly the wide variety of wastes and
solids contents to be encountered.
3. Filtration with a 0.45 micron filter, along with appropriate
filter aids, is adequate for solid-liquid separation prior to
and between elutions of the recommended batch leaching test.
4. Because of the major differences in a waste's leaching char-
acteristics as a result of the leaching media composition,
no one media can give results adequate to describe properly
the leaching characteristics of a waste. The use of distilled
water to model mono-landfill conditions, municipal refuse land-
fill leachate to model co-disposal with municipal refuse, and
appropriate special leachates to model co-disposal with other
industrial wastes is recommended. These landfill possibilities
represent the extremes which may occur in a municipal sanitary
landfill, in which leachate composition may be controlled by
the waste itself, actively decomposing municipal solid waste
or another specific waste present in the landfill.
5. The leaching characteristics of an actively decomposing municip
refuse landfill leachate are greatly different from those of
distilled water. A synthetic municipal refuse leachate has
been developed which models the pH, redox potential, ionic
strength, and complexing capability of actual leachate.
6. Information regarding both concentration and release of leached
components from a waste is necessary for an understanding of
the potential effect of landfill ing that waste on water quality
No one leaching test procedure is adequate for providing both
concentration and release information; therefore, separate batcl
procedures should be used, one providing information on maximum
concentration, the other on maximum likely release of contami-
nants from a waste.
-------
7. The operating conditions and test variables as evaluated and
recommended were reasonable and adequate for the wastes tested
(e.g., three elutions, 24 hours per elution, 1 to 10 dry weight
waste to liquid volume ratio, etc.).
8. Proper interpretation of the results from the recommended pro-
cedure is critical to its usefulness. The test was designed
to be aggressive; the numbers obtained are expected to be
maximum values which will not be attained normally in an
actual landfill.
-------
SECTION 3
RECOMMENDATIONS
Many additional studies could be suggested as a result of this
project, of which the following four are felt to be of particular
importance.
1= The recommended leaching procedure should be used on a wider
variety of wastes than was possible in the present study, and
revised if warranted.
2. The procedure should be-used on identical wastes by different
laboratories to check on reproducibility from laboratory to
laboratory.
3. There is a lack of data regarding leachate generation at full-
scale industrial waste landfills with which results from the
laboratory leaching procedure can be compared. Field verifica-
tion studies are needed in which unattenuated and indiluted
leachate from specific industrial wastes in mono- as well as
co-landfill situations can be compared with appropriate leach-
ing test results9 preferably on a long term basis.
4. Additional methods of interpretation of leaching test results
should be sought and refined as new data (especially from fielc
verification work as in point (3)) become available.
-------
SECTION 4
BASIC CONCEPTS
This chapter will discuss the philosophy of leaching tests and the
test variables affectinq the leaching test, review some of the leaching
tests that have been developed, and discuss briefly the procedure which
evolved from this work.
Intensive vs. Quick Tests
Two general approaches can be use.d to evaluate the Teachability of
waste material: (1) a very intensive study of waste leaching charac-
teristics, or (2) a quick test using standardized procedures. The inten-
sive study gives more information about the leaching characterists of a
waste. Test conditions can be varied as needed, and the effects of differ-
ent variables on the leaching characteristics can be studied. Such a
test takes considerable time, money and personnel. The standardized test
uses only predetermined testing conditions, and so cannot show the effects
of the different variables of the waste leaching pattern. It can, however,
give useful information in a short time which when properly interpreted
can give an indication of the leaching characteristics of a waste. It
is much cheaper, faster, and simpler than the intensive study.
Wastes generated in large quantities should be subjected to the
intensive study, particularly wastes that are generated at different
sites throughout the country but are of relatively uniform composition,
e.g., fly ash or scrubber sludge. However, for the many wastes that are
produced in relatively small amounts, a standard leaching test is more
appropriate. The small amount of waste produced does not justify the
expense involved in the intensive study unless the waste is of particular
concern because of its characteristics or landfilling situation.
In an intensive test, factors affecting the test results will be
varied and their effects observed and analyzed. In the standard test
these factors will be set beforehand and their effects on the test
results will not be observed. It is important to be aware of the test
factors which are set in the standard test and their potential effect
on the test results so that a proper interpretation can be made of the
results.
Ideal and Practical Leaching Tests
Ideally"a leaching test would determine four characteristics regard-
ing the release of a parameter, A, from a waste:
1. the highest concentration of A to be found in the leachate;
2. the factors controlling this concentration,
3. the total amount of A available from a give amount of waste, and
4. the release pattern of A with time.
5
-------
The last characteristic includes the kinetics of the release, physical
or chemical changes occurring in the waste as it is leached, any effects
of these changes on the release of A, and the influence of the waste on
the leachate. Water quality standards are given in terms of concentra-
tion and since many toxic effects are concentration dependent as are
most chemical reactions, concentration is of obvious interest. Maximum
release is Important when predicting the total amounts of A that may be
leached from the waste in a landfill. It is also of importance when A
may be accumulated, whether due to biological uptake or chemical proc-
esses (e.g., sorption onto soil, precipitation, etc.). Accumulated mate-
rials may be released at high concentrations if conditions change. With
the four characteristics determined by the leaching test, the potential
hazard of a waste can be evaluated, and the suitability of landfill ing
as a disposal technique assessed.. The information from the test could
also be used along with other information, to design waste processing
or landfill ing procedures so as to minimize the release of A from the
waste.
A standard leaching test, as defined herein, will not give enough
information to predict completely the four characteristics mentioned
above; however, it will show the behavior of a waste under a prescribed
set of conditions. These conditions can then be related to landfill
conditions through modeling and careful selection of test conditions,
and through correlation studies between test and actual landfill results
Correlation studies serve both to relate the non-modeled conditions to
landfills and to verify the modeled conditions. With careful interpre-
tation of results, an estimation of the behavior of a waste in a landfil
can be made from standard test results.
Since the purpose of the test is to evaluate the leaching potential
of a waste, it is reasonable to use an aggressive test to model a worst
case situation. This is a conservative rationale. Further testing can
then be done, if warranted, using conditions more typical of the long-
term landfill situation.
A test which extracts only those components that would be leached
in a landfill and extracts them in the same pattern that they would be
extracted in a landfill is needed. A chemical solvent or series of
solutions which would extract only Teachable components would be ideal.
Serial extraction procedures have been developed for soils and sediments
however, such procedures are based on a comprehensive understanding of
the extraction process. This understanding requires that the chemical
composition of the leached material and the chemical interactions be-
tween the material and the leaching solution be understood, and that
the composition of the leached material be fairly consistent. Most of
the wide array of landfilled wastes do not meet these criteria. The
leaching test must then attempt to model landfill conditions, so the
results are more readily related to full-scale landfill situations.
-------
Batch and Column Tests
Two types of tests are commonly employed for determining the leach-
ing potential of a landfilled waste—batch and column tests. In batch
tests, a properly prepared sample of the waste to be tested is placed
in a container along with leaching media. After a suitable period of
time, and under conditions specified as being appropriate to the test,
the elutriate or leachate is separated from the waste and analyzed to
determine the material leached from the waste. Column tests, in which
the waste is packed in a column and the leaching solution passed through,
is a closer approximation of landfill conditions than a batch test, at
least at first glance. The column test simulates both the waste—leach-
ate contact (except around the column edge) and the rate of leachate
migration found in landfills. The column test also is good for predict-
ing the release pattern of A with time,' since it models the continuous
leaching and long time periods found in landfills. However, column tests
have several disadvantages, such as the following:
1. problems arising from channeling and nonuniform packing,
2. potential unnatural clogging,
3. possibly unnatural biological effects,
4. edge effects,
5. long time requirements, and
6. difficulty in obtaining reproducible results even if done by
experienced lab personnel.
All of these difficulties, but particularly the time requirements for
an adequate column test (months to years), suggest that a batch test
be chosen as the standard testing procedure. Both batch and column
tests might be used in an intensive study.
Factors tn a Batch Test
There are several factors affecting a parameter's concentration in
the batch test elutriate which need to be considered in designing a
leaching test. These factors are given in Table 1.
Even though specific values for each factor must be set or reported
in order to obtain reproducible batch test results, the factors are
interdependent, and values chosen for one may limit the range of reason-
able values which may be selected for another. For example, a very high
solid to liquid ratio may result in saturation concentrations for many
elutions for species leached from a waste, unless the time per elution
is shortened.
Of particular interest in the development of a leaching test are
the test conditions. These are discussed individually below.
-------
The leachate produced in a mixed municipal/industrial landfill is the
most difficult to model, since the material entering the landfill will
likely vary in composition. In this case, two approaches may be used
in the selection of leaching media. If the wastes in the landfill are
known, a synthetic leachate can be developed based on characteristics
of those wastes. Alternatively, a series of leaching, solutions can be
used, each emphasizing a single leaching parameter—i.e., acid base,
complexer, organic solvent, etc. Results obtained using different
leaching solutions would indicate what types of wastes might be co-
disposed with the waste in question. For example, a waste which
released large amounts of an undesirable parameter under acidic leaching
conditions should not be landfilled with acid or acid producing wastes.
The use of distilled water or. other mild leaching solutions allows
the waste to create its own leaching environment, whereas, a synthetic
leachate or strong chemical solution essentially controls the leaching
environment. For example, a waste containing small amounts of a leach-
able basic salt will raise the pH of a distilled water leachate, and
only materials that are soluble in basic solutions will be found in the
leachate. Conversely, use of a synthetic municipal leachate which is
heavily buffered, or an acid leaching solution, will probably neutralize
the basic salt while maintaining an acidic pH. In the first case the
waste controls the pH of the solution, while in the second case the
leaching media is the controlling factor.
B. Solid to Liquid Ratio
Solid to liquid ratios (or waste to eluent ratios) used in the test
can have profound effects on test results. The concentration of a very
soluble parameter will be directly dependent on the solid to liquid ratio
(3/1). On the other hand, parameters for which concentrations are con-
trolled by solubility will not show S/L ratio effects, but rather will
have the same concentration at all S/L ratios, provided enough solid is
present to saturate the system. S/L ratios can also affect concentration
if adsorption or desorption processes are controlling the concentration.
In a given waste, several chemical constituents may be of interest.
These may have different factors controlling their concentrations, and so
may show different dependencies on the S/L ratio. Several currently
available leaching or elutriation tests start with high S/L ratios and
saturated conditions, then decrease the ratio until unsaturated condi-
tions are reached. This procedure could be complicated if more than
one parameter of interest reached saturation at different S/L ratios.
The S/L ratio encountered by a drop of leachate percolating through
a landfill will be very high, by the very nature of percolation. If there
were extensive channeling in the landfill, however, this would not be true
The choice of a solid/liquid ratio for use in the test is based on
practical considerations. A very high S/L ratio, such as is used in
the saturation test, is most likely to result in many components being
saturated. This makes it difficult to estimate the total release of a
10
-------
component from the waste, since many elutions will be necessary to elute
the Teachable fraction of the component. Also, it is often difficult to
obtain enough leachate for analysis with a high S/L ratio. On the other
hand, a very low S/L ratio can produce very low concentations of the
parameters of interest, leading to analytical problems.
An interesting approach to the selection of an S/L ratio is used
in the State of Illinois E.P.A. test as reported in reference (1). The
ratio to be used for Waste R is calculated from the equation R = 5.34 D,
using the waste density (D) for the wet waste and a constant based on
the average annual rainfall in Illinois. Thus, the S/L ratio is based
on volume rather than weight, and can be readily interpreted in terms
of landfill conditions and annual rainfall. If the results of a teaching
test are to be directly related to landfrll conditions, a correlation
between the annual rainfall, the waste density, and the test S/L ratio
will need to be made in order to determine how much leachate a unit area
of waste will contact per unit time, and thus the time span to which the
S/L ratio used in the test corresponds. The Illinois test is interesting
in that the correlation is determined before rather than after the test
is performed.
C. Time per Elution
Ideally, either each elution would allow the parameter of interest
to come to equilibrium, or it would be designed to study the release
kinetics of the parameter. In practice both situations are difficult to
obtain. Different parameters may equilibrate at different rates. Lee
and Plumb (2) found four release patterns in a Teaching study using
taconite tailings, as shown in Figure 1. The time span for their experi-
ment was 500 days. The experiment used a very low S/L ratio (5 to 35 gm
taconite per 10 liters distilled water), with periodic samplinq. Not only
did equilibration times for different parameters vary widely, but for some
parameters a series of reactions occurred which produced concentration
maxima with subsequent concentration decreases. The varieties of release
patterns found make it apparent that no one sampling time could be chosen
which is the best for each of the release patterns. Nor can a short
leaching test be assumed to measure equilibrium concentrations of a param-
eter, or even to determine all the parameters that would be released from
a waste. Of course, the four patterns found by Lee and Plumb are not the
only release patterns possible; different wastes may have different and
possibly unique release patterns.
The selection of an elution time is arbitrary. Some considerations
to apply, however. The test should be long enough to allow rapidly
equilibrating species to approach equilibrium and analytically deter-
minable amount of most species to be released, yet short enough to mini-
mize biological growth in the test chamber, secondary effects, and con-
sistent saturation of species of interest. Biological growth can produce
constantly changing conditions and could make test results very difficult
to interpret. Consistent saturation of chemical species would require
many elutions to be performed. Finally, the time chosen should be con-
venient to personnel, if possible.
11
-------
Graph
Type
Asymptotic Release
Example
Specific Conductance.
Alkalinity Ca, Mg
and others
Exponential Release
Silica (a slow
hydrolysis step
needed before Si is
solubilized)
Release followed
by loss from
solution.
Cu, Zn-loss due
either to rising
pH in solution, or
absorption back onto
solids
£
•M
-------
By removing samples at various times during an elution, one obtains
information about the release kinetics of a rapidly equilibrating specie.
However, unless the contact time between the waste and leachate in ths
Jandfill are known, this information may be difficult to apply to a land-
fill situation. It could be used to determine the equilibrium concentra-
tion of a parameter. The additional work involved makes this determina-
tion more appropriate in an intensive test rather than a standard leach-
ing test.
D. Number of Elutions
The information obtained from more than one elution often justifies
the extra work involved. Successive elutions can indicate the release
pattern of a parameter over time, and'often can give an idea of the
factors affecting the release of the parameter. Successive elutions
are particularly important when the release of one parameter, A, is
inhibited by the release of another parameter, B. For example, imagine
a leaching situation with a waste containing a soluble basic parameter
(e.g., a carbonate) and an acid soluble-base insoluble component (e.g.,
a trace metal), being leached by an acidic leachate. The carbonates
in the waste will neutralize the acid leachate until the carbonates have
been leached from the waste. Incoming acidic leachate will then reestab-
lish acidic conditions and bring the trace metal into solution. If only
one elution was used, or if the test was ended before the acidic pH
had been reestablished, the potential for trace metal leaching would be
completely overlooked. More than one elution can also-sometimes indi-
cate the factors controlling the release of a soluble parameter—steady
concentrations over several elutions may indicate solubility or desorp-
tion control, whereas, a rapidly falling concentration indicates washout.
The additional information obtained from repeated Teachings needs
to be balanced against the extra work involved. The experience of the
authors is that the most useful information is obtained in the first
several Teachings. One reasonable approach is to set a set number of
elutions, say three to five, with more elutions suggested if an indi-
cator parameter, e.g., pH, has not returned to a baseline value.
In the discussion above, it has been assumed that the same waste
sample has been eluted several times with fresh leachate. An alterna-
tive approach is to use the same leachate sample to elute several fresh
samples of waste. This procedure provides information regarding the
maximum concentrations that a parameter can reach in the leachate,
rather than indicating release characteristics. By using both elution
techniques—replacing either the leaching media or the waste in subse-
quent elutions—one can obtain considerably more information about the
waste than by using either procedure alone.
13
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E. Temperature
Temperature should have an effect on the leaching pattern of a
waste due to its effects on solubility and reaction kinetics. Gener-
ally, however, leaching tests have been conducted at room temperature.,
and the effects of temperature on the leaching pattern of a waste
within the range of average laboratory temperatures may not be great
enough to justify specially controlled temperature conditions. Tem-
perature-should be measured and reported, however. Occasionally,
temperature control can be very important if the waste itself is
affected by temperature. For example, if a solid component of the
waste melts at room temperature, constant temperature conditons are
important.
F. Agitation Technique
An agitation technique which promotes mixing without causing waste
particle or container abrasion is needed. Agitation is needed to avoid
concentration gradients between the leachate in contact with the waste
and that at a distance; however, overly vigorous agitation can cause
particle abrasion (Boyle, et. al. (3)) and give unnaturally high
results. One agitation technique, used in some tests, involves shaking
for a short time followed by settling. The authors found that this
procedure results in the development of significant concentration
gradients between the settled waste and the leaching solution, and thus
is not aggressive enough for a good leaching test. Other methods, such
as reciprocal shaking, wrist action shaking or circular shaking are more
suitable provided they produce well-mixed systems and are slow enough so
as to not promote abrasion.
6. Surface Area Contact Between Waste and Leachate
For some wastes, the amount of surface area in contact with the lead
ing solution can be important in controlling parameter concentrations in
the leachate. For example, viscous liquid or solid wastes which are
water-impervious but which contain water soluble parameters, can show
this behavior. Such species can be leached from the surface of the
waste, where they are in contact with the water, but not from the
interior of the waste since the waste is impervious to water. Dif-
fusion through the waste is generally too slow for these species to
reach the surface.
If this situation is known to occur with a particular waste, the
surface area of the waste in the test should be measured and the re-
lease calculated per unit surface area as well as per gram. Interpre-
tation of this data, however, may be difficult unless it is known how
the waste is going to be landfilled and whether physical breakdown of
the waste occurs with time. The surface area of a waste may be con-
trolled initially during sample preparation before the test by grind-
ing, cutting, etc., or by the agitation technique.
14
-------
Summary of Existing Tests
Several batch leaching tests have been developed. A survey of
some of the existing tests has been done by the Mitre Corporation (1).
A summary of the surveyed tests (plus two additional tests) is given
in Table 3. The table provides both the range and the frequency at
which values occur within the range for each of the various test vari-
ables discussed in this section. For those factors for which the
selection of a value is somewhat arbitrary, as in the S/L ratio or the
elution time, the range of values reported might be given consideration
in the specification of values to be used in a test, and an average
value (median or mode) used. For other factors (especially the number
of elutions, for example), average values have little meaning. The
wide variety in all the specified factors indicates the need for a
standardized test so that results on different wastes and by different
laboratories would be comparable.
Concluding Statement
This section has discussed concepts leading to the general test
procedure recommended as a result of this study. Also presented were
discussions about each of the major test variables and how the selec-
tion of a particular value for each variable relates to the outcome of
the procedure with a given waste. The remainder of this report will
consider each aspect of the recommended leaching test in detail, start-
ing with sample preparation and the solid-liquid separation. Next will
be a discussion of each of the leaching procedure variables, including
data representative of those used to study the effect of each variable
on the leaching test results and eventually to set recommended operat-
ing levels for each variable. Finally, a section summarizing the
recommended procedure and methods of data presentation and interpreta-
tion will conclude this report.
The amount of data obtained in this study is too much to incorporate
in the body of the report without making it difficult to follow. Accord-
ingly, examples of data are presented as appropriate, but the bulk of the
data is presented in the Appendix. Typically, the Appendix presents
results from different wastes or additional chemical species beyond
those incorporated in the body of the report.
15
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TABLE 3. SUMMARY OF EXISTING LEACHING TEST VARIABLES
(NUMBER OF TESTS SPECIFYING EACH OPERATING VARIABLE INDICATED)
Leachates
H20 (dist, deion, dist-deion or unspecified)
H?0 with pH adjustment or simple acid base
Site specific
Acetate buffer
Synthetic municipal landfill leachate
Synthetic natural rainwater
Bacterial nutrient media
Tests with more than one leachate
No.
17.
5
1
Solid-liquid ratio
Time per elution
No. of elutions
Agitation
range 1:1-1:500
range 30 min-
10 days
range 1-10
<1:4 1:4
4 4
<1 hr 1-24
hrs
1 3
1 3
15 1
shaker, stirring & gas agitation
with extended settling times.
1:5
3
24
hrs
7
5
1
used.
1:10
5
48
hrs
3
7
1
Two tests
>1:10 varied calculated
2 2 1
72 >72 to
hrs hrs "equil."
232
10
2
use short agitation times
Surface area
unspecified
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SECTION 5
SAMPLE PREPARATION AND SOLID-LIQUID SEPARATION
Overview of Leaching Test Procedure and Hastes Tested
The organization of this report is such that the reader will not
have a complete picture of the recommended leaching test until after
a discussion of the many test variables. To avoid this, and to provide
a basis for understanding the discussion and test procedures used in
describing work related to each test element, it is necessary at this
point to define in broad terms the batch leaching test procedure used
and discuss the industrial wastes us-ed. Details regarding the pro-
cedure, and the experimental background which determined the recom-
mended operating conditions, will be presented throughout the remainder
of this report.
Unless specified otherwise, leaching tests were run on whatever
portion of a waste was not filterable through a 0.45 micron membrane
filter. The waste was contacted with leaching media (normally dis-
tilled water) in a flask in the ratio of 1 part waste (wet weight) to
7 parts media, by weight. In later experiments, after it was found nec-
essary to work with dry weight for consistency in working with a variety
of wastes, a ratio of 1 part waste (dry weight) to 10 parts media was
used. Usually 200 ml of media were required for each elution in order
to obtain sufficient leachate for analytical purposes. The mixture was
agitated by one of many methods evaluated during the study, all of
which were designed to mix the waste and leaching media to promote the
leaching process. After each 24 hour elution, the waste and leachate
were separated with a 0.45 micron filter, the leachate analyzed, and
the waste returned to the container and fresh media added for Procedure
R. In Procedure C the waste was replaced with fresh waste and a portion
of the leachate removed for analysis. Three elutions were performed,
and standard analytical procedures were followed for leachate analysis
as specified in Standard Methods (4). Most elemental analyses were done
by atomic absorption. Because of the type of data read-out with this
instrument, conentration values were obtained even though they were below
the detection limits cited by the manufacturer. In such cases the mea-
sured values will be presented, as well as the cited detection limits, but
they must be considered unreliable and approximate (e.g., Figure 25).
The wastes were obtained from several sources. They were selected
to provide a range fn chemical species and levels of solids contents.
The wastes, and the symbols used in this report to identify them, were
as follows:
1. shredded municipal refuse (residential and light commercial)
obtained from the City of Madison shredding facility;
2. fly ash (unspecified further) from a power plant in Wisconsin;
3. paper mill sludge (N or unspecified further) from a paper mill
in Wisconsin;
17
-------
4. paint waste (AA) from an automobile assembly plant;
5. clarffier sludge (AA) from an automobile assemWy plant;
6. fly ash (AA) from an automobile assembly plant;
7. fly ash (EPA) provided by EPA via Chem-Trol Pollution Services,
Inc. of Model City, New York;
8. paper mill sludge (EPA) similarly provided by Chem-Trol;
9. a CuO-Na«S04 slurry provided by Chem-Trol; and
10. wastewater treatment s-ludge (EPA) provided by Chem-Trol.
Most of the test development work utilized wastes 2 through 6 because
these wastes were readily available in large amounts, and were expected
to be reasonably constant in composition from one sampling date to the
next. Fortunately, sufficient amounts of wastes were obtained the
first time to avoid the need for resampling. Wastes 7 through 10 were
supplied by EPA and were used only for major experiments to avoid the
need for resampling. The wastes were stored in a cold room at 4°C.
It should be noted that once developmental work had been accomplished
and the recommended procedure established in the first phase of this
research, many other wastes were tested to provide experience using a
wider variety of wastes. The results of -the second phase are reported
separately.
Sample Preparation
Developing sampling and sample preparation techniques for obtaining
representative and reproducible samples of industrial wastes was not a
part of this project, except for the development of a solid/liquid sepa-
ration procedure. Sample preparation is very important however. Stand-
ardized methods for sampling many industrial wastes are available, e.g.,
ASTM standards for various wastes, and it is suggested that these be
used where possible.
In working with the various wastes used in the background study,
a number of problems regarding sample preparation were experienced.
These are discussed to illustrate some of the types of problems which
may be encountered.
• The problems encountered fall into the following main areas:
1. representative sampling,
2. particle size reduction,
3. leachate absorption by the solid,
18
-------
4. homogenization, and
^ 5. determination of dry weight.
These problems will be discussed separately.
A. Representative Sampling
If a waste consists of particles of different sizes, obtaining
representative samples can be difficult. For example, the copper oxide-
sodium sulfate slurry contained large crystals (softball size) in a thick,
particle-laden slurry. In order to obtain representative samples, it was
necessary to divide the whole bucket.into the crystal and syrup fractions,
weigh each fraction, grind the crystals with a mortar and pestle, then
recombine the ground crystals and syrup in their original proportions.
The problem of wastes containing large bulky solids in a slurry will
probably not be uncommon.
Another example of a particle size related problem occurred with
the fly ash samples. Although fly ash consists of relatively small
particles, sieve analysis shows that the ash contains several different
size fractions. The smallest particles are difficult to sample consist-
ently when interspersed with the larger particles. One way to obtain
consistent and representative samples is to separate the fly ash into
different size fractions using a sieve, weigh each fraction, then recom-
bine each sample according to the weight.distribution of the original
waste. A sand splitter may also be used for obtaining representative
samples. The fly ash may need to be dried before sieve analysis.
The need for accurate particle size analysis and sampling is shown
in Figures 2 and 3. Two fly ash particle sizes, less than 0.5 mm and
between 0.5 and 1.00 mm, were leached with distilled water, using
different types of agitation to be described later, and at different
temperatures. It is apparent from the results presented in the fig-
ures that the pH, specific conductance and iron concentrations in the
leachate are a function of the particle size of the fly ash. The
elution rate is higher for the smaller particles, presumably due to
the higher surface area of the smaller particles.
B. Particle Size Reduction
Bulky solids need to be reduced to smaller size, primarily to make
handling easier and to promote leaching. A variety of different tech-
niques can be used for the reduction. The crystallized solids in the
copper oxide-sodium sulfate sludge were ground with a mortar and pestle.
Some harder wastes, such as bottom ash, iron slag, etc. may need to be
cut to proper size, perhaps a 1 cm diameter particle. However, if such
wastes can be shown not to break down in a landfill, then the surface
area of the waste in the test should be determined, and release calculated
on the basis of surface area as well as weight. Evaluation of the leach-
ing potential of such wastes should take into account the probable
surface area of the waste in a landfill and the corresponding release.
19
-------
1.2
I.!--
1.0
SERIES PVI FLYASH
CONDUCTIVITY x 104
!.3T
TEST NO.*
3
4
2
DAYS
1.0
6-
5
pH
44
3
i a
DAYS
pH
4
I 2
DAYS
Figure 2. Differences in conductivity and pH in leachate
from two fly ash particle size fractions.
*Note: see Figure 3 for key.
20
-------
SERIES PVI FLY ASH
ISOmL OF H2O+• 15 g/L NnHSO,-*- Co-i-2i.5g FLY ASH, (l:?f
REFILLED EACH DAY WITH 150 mL OF HO
6000T
5000- •
en
< 4000-
3000 ••
if
S
Ul
2000 ••
1000- •
^
UJ
u
tn
ui
X
CO
23
u. -•
e>
DAYS
DAYS
TEST NO. AGITATION 0" VALUE LINE TEST NO. AGITATION j6 VALUE
I I SHAKE .5<0
-------
Several processes for reducing Teachability of waste have been
developed, either through incorporating the waste in a solid matrix
or by covering the waste with a stable impervious coating. These
wastes may need special consideration with regard to sample prepara-
tion. If it can be shown that these wastes do not physically break
down in a landfill or in the process of landfilling, the wastes should
not be ground or cut up any more than necessary as the leaching char-
acteristics of the ground waste in the test may be completely different
from the characteristics of the containerized waste in the landfill.
Although not specifically tested as part of this study, it seems
reasonable to cut9 crush, or specially make wastes originally existing
as large blocks to yield particles approximating the size equivalent
to a 1 cm cube9 for example. Th.is- particle size is small enough to
work in the procedure, yet large enough to not increase drastically
the surface area per unit weight waste exposed to leaching (see
Figure 4). This is observed by plotting the surface area per volume
contained for cubes of varying dimension (a/v = 6s2/s3 - 6/s). In
interpreting the resultss the use of a factor describing the change
in surface area as a result of particle size reduction might be help-
ful. For example, reducing a unit weight of waste originally in 10 cm
cubes to 1 cm cubes multiplies the exposed surface 10 times.
i 25
E
o
— 20
UJ
UJ
or
15
10
0
0 0.5 1.0 1.5 2.0 2.5 3.0
CUBE SIDE DIMENSION
(cm)
Figure 4. Effect of cubic particle size on surface
area per unit volume particles.
22
-------
C. Leaching Media Absorption by Wastes
Absorbent wastes that are significantly below field capacity may
need to be brought to field capacity, either with distilled water or
with the original liquid associated with the solid, if any. Otherwise,
the leaching media may be absorbed by the waste and not available for
leaching analysis. This was found to be a particular problem with
paper mill sludge and the municipal waste where the latter had to be
dried before grinding, then rewetted after grinding. Dry fly ash was
also prewetted before leaching for this reason.
D. Homogenization
With a few wastes, a phase separation had occurred by the time the
sample had reached the laboratory. One such waste used in the second
phase of the study and not reported here was a coal tar sludge, in which
the coal tar was floating on a water layer. The coal tar had the con-
sistency of road tar, and stuck to anything it contacted. It would be
next to impossible to homogenize the water and tar layers in this waste.
Rather than homogenize the waste, the coal tar was used by itself in the
leaching test, and the water layer could have been analyzed directly.
The same situation occurred with a food waste and a grain-processing
lipids waste, also tested in the second phase of the study. In both
cases a solid organic material was floating on a water layer. Homog-
enization in such cases can be very difficult, and it is suggested that
the organic portion be tested separately from the aqueous portion, in
each case beginning with solid-liquid separation, etc. as appropriate.
E. Determination of Dry Weight
In order to accommodate wastes of different solids contents, to be
able to compare the leaching potential of different wastes, and for leach-
ing test procedural purposes, as will be discussed later, it is neces-
sary to be able to define the dry weight of a waste. This turned out
to be one of the more perplexing problems encountered. One would think
that a routine procedure for determining the dry weight of a waste
could be developed easily. With wastes containing non-volatile solids
and water, the procedure is in fact routine. The waste is dried at a
specified temperature either for a specified time or until constant
weight is obtained (e.g.. Standard Methods, 13 ed. (4)). Depending
on the temperature, a portion of the water will be driven off (e.g.,
interstitial water, water of crystallization, etc.). However, for
wastes containing volatile or semi-volatile organic compounds, the
procedures given ambiguous results. The weight continues to drop even
after long drying times as the partially volatile components are slowly
driven off. Examples of this situation are given in Figures 5,6, and
7 for three wastes (from phase 2). Even after 500 hours' drying at
105°C, the weight of these wastes continues to drop. It is not obvious
what the dry weight of the waste is in these situations.
23
-------
ro
100
8-
I
19'
80
^60
40
HEALTH a BEAUTY CARE WASTES
WASTE NO. 4 CHICAGO
70° C
100
200 300
TIME, hrs
400
500
Figure 5. Long term drying characteristics of health and beauty care waste.
-------
100
ro
en
I 1 1
LONG TERM DRYING CHARACTERISTICS
PAINT a INK WASTES, WASTE N0.2 CHICAGO
200
300
TIME, hrs
400
500
Figure 6. Long term drying characteristics of paint and ink waste.
-------
ro
en
WATER LAYER FROM OIL/WATER TANK +> SPECIFIED
AMOUNTS OF HgO, 105° C
• 0 % H20
• 25% H20
A 50% H20
90% H20
200 300
TIME, hrs
400
500
Figure 7, Long term drying characteristics of water layer from an oil-water tank
with various amounts of water added.
-------
Dry weight rather than wet weight is used to avoid problems of
variable drying of the waste. For example, a 10 gm sample of a waste
containing 50% water contains 5 gms of the waste itself. If the waste
should dry so that it has a 10% water content, 10 gms of the waste now
contain 9 gms dry weight. Since the release of materials from the waste
is often dependent on the amount of waste present, these two samples might
not behave the same in a leaching test. However, if a 10 gm dry weight
of sample is used in the test, the same amount of waste is present no
matter what the water content. The same problem can occur with volatile
organic solvents as well as with water. Logically, to avoid problems
due to drying, these solvents should be treated in the same manner as
is water, i.e., removed from the sample before the determination of the
weight. However, there is no clear distinction between volatile and
nonvolatile organic compounds, as there-is between common inorganic mate-
rials. It is interesting that the standard method suggested by ASTM for
determining the moisture content in wood (D 1860 63 (reapproved 1976))
involves distillation rather than drying. Possibly, different drying
procedures need to be prescribed for aqueous and organic samples.
Dry weights for the wastes tested were determined by drying at
105°C for 24 hours. Since the same procedure was used for each test,
the results are comparable. For several wastes, particularly those
mentioned in Figures 5 through 7, the dry weight is test condition
specific, and is not an inherent property of the waste.
Solid-Liquid Separation
A preliminary step in the leaching test is the separation of the solid
and liquid components of the waste. "Solid" and "liquid" in this context
are defined by the separation. The rationale for the separation process
is that the solid and liquid components of the waste will probably separate
in a landfill. As illustrated in the following example, three separation
processes might occur (Figure 8). After the waste is deposited in the
landfill, the liquid components could flow downward due to gravity, be
absorbed by surrounding materials, or move away from the waste by capil-
lary action. In municipal refuse, the predominant identified material is
often paper so that the absorption process is probably important. The
solid material remaining after the liquid components have moved will be
subjected to leaching by whatever leaching media is available in the land-
fill. Thus, it is more realistic to use only the solid portion of the
waste in the leaching test, and to analyze the liquid portion separately,
than to use the whole waste in the leaching test. The movement of the
liquid portions of a waste from a landfill is not necessarily dependent
on the leaching process.
Separations occurring in landfills will depend on the environment
immediately adjacent to the waste and on the landfill conditions and
design. Modeling such potentially varied conditions in the laboratory
is very difficult. Therefore, it was considered more useful to develop
a widely applicable and relatively easy solid-liquid separation scheme.
Although the separation scheme is not unrealistic with regard to the
separation that might occur in a landfill, it should not be considered
an attempt to model that separation.
27
-------
municipal
refuse
capillary action and liquid absorpti
municipal refuse
absorption and capillary
flow
gravity flow to
underlying soil
Figure 8. Movement of moisture from waste in a landfill.
TABLE 4. A List of Several Particle Separation Techniques
Filtration
Sedimentation
Elutriation
Centrifugation
Particle Electrophoresis
Electrostatic Precipitation
Flotation
Screening
Several particle separation techniques are given in Table 4. Of
these, screening, filtration and centrifugation where chosen as being
the most appropriate for the test scheme. Filtration was chosen as a
final step in the scheme, since it is easily applied, readily available
and standardized, inexpensive, and roughly approximates the separation
processes in the landfill., Filtration operationally defines solids and
liquids—anything that will pass through the filter is liquid, and all
that does not is solid. It is important that the nature of waste com-
ponents not be changed, but rather that they simply be separated. This
precludes addition of coagulating or deemulsifying agents, for example.
-------
The separation scheme, in Figure 9, can be described as follows:
If the sample is not obviously a solid, an attempt is made to filter
the waste through a 0.45 micron filter. If the liquid portion of the
waste is not water soluble, the filter paper and support frit should be dry
when the sample is placed in the filter allowing the liquid portion of
the waste to wet both. If the sample will not filter, various other
separation techniques are used to aid in the filtration. First, pres-
sure filtration is employed using pressures up to 80 psi. This merely
speeds up the filtration process and does not alter the nature of the
separation. Anything that does not separate during filtration is cen-
trifuged. If separation occurs during centrifugation, the liquid por-
tion (centrifugate) is filtered through a 0.45 micron filter. Anything
that will not filter after centrifugation or separate during centrifuga-
tion is considered a solid and is used -in the leaching test. Occasionally,
other techniques may be used if there are obvious reasons for their use.
For example, sieving can be used to remove large particles that would
result in clogged filters. In cases where the sample has previously
separated through sedimentation or flotation, the solid and liquid
portions of the separated waste can be treated separately. With all
wastes, however, any liquid portion used for direct analysis must have
been filtered through a 0.45 micron filter.
The selection of filter pore size is an important consideration.
A small pore size will retain particles in the solid portion that might
be considered liquid if a larger pore size were used. For example,
hydrous ferric oxide (ferric hydroxide precipitate in water) precipitates
in colloidal sized particles. A 0.45 micron pore sized filter will trap
many of the colloidal sized particles in the solid portion, whereas a
larger pore sized filter, e.g., 8.0 micron, will allow most of the
colloidal sized particles to pass through the filter and so be considered
liquid. Analysis for iron in the filtrates from the two pore sizes would
give different values for the iron concentration in the "liquid" portion.
An example of this situation is shown in Figure 10. A leachate contain-
ing hydrous ferric oxide precipitate was filtered through filters of dif-
ferent pore sizes, with the resulting "dissolved" iron concentrations
presented in the figure. As can be seen, the dissolved iron concentration
is much higher in the 8.0 micron and glass filter filtrate. Many mate-
rials may occur in or be associated with colloidal sized particles, so
it is important to standardize the pore size used and to keep in mind
the importance of the pore size on the designated liquid and solid frac-
tions.
A filter pore size of 0.45 micron was selected for the final filtra-
tion step on the basis of its wide use in water and wastewater analysis,
its availability in filters with carefully controlled pore sizes, and
since it is not an unreasonable pore size for modeling landfill siutations.
Particles larger than 0.45 micron~occur in leachate, as evidenced by
suspended solids measurements and the presence of bacteria, yet such
materials are usually removed by passage through soils, as evidenced by
the low suspended solids content of most groundwaters.
29
-------
YES
IS SAMPLE OBVIOUSLY A SOLID ]
NO
pro SLT I
CAN SAMPLE BE FILTERED USING
SOLVENT TO WET FILTER
YES
NO
USE SOLID FOR SLT,
ANALYZE LIQUID AS
AVAILABLE
YES
CAN SAMPLE BE FILTERED
USING A PRESSURE FILTER
NO
USE SOLID FOR SLT,
ANALYZE LIQUID AS
AVAILABLE
YES
CAN SAMPLE BE SEPARATED
USING CENTRIFUGATION
SOLID
LIQUID
TO SLT
CAN SAMPLE BE RLTERED
USING SOLVENT TO WET FILTER
YES
NO
-L
USE SOLID FOR SLT,
ANALYZE LIQUID AS
AVAILABLE
TO SLT
Figure 9. Solid-Liquid separation, scheme.
30
-------
Fe, ppm
50 -r
40-
30--
20--
IO--
0
A pH~2
a H/v7
GLASS FIBER
FILTER
FILTER SIZE
0.45A
Figure 10. Comparison of the "dissolved" iron concentrations
in municipal refuse leachate after filtration through
various pore sizes.
31
-------
The purpose of the centrifugation step is twofold: (1) to remove
particles of diameter larger than approximately Q.4S micron from solu-
tion; and (2) to aid the removal of any emulsions that may be present
in the wastes. Emulsions can be absorbed by dry solids in the same way
a nonemulsified liquid can, yet will behave on a filter as a solid.
The choice of centrifugation time and speed is made with these ojectives
in mind. If the specific gravity of the particles are known, and if the
suspending liquid is basically water, the centrifuge time and space
needed to separate a 0.45 micron particle a distance equal to the length
of the centrifuge tube can be calculated from Stoke's law and the Relative
Centrifugal Force tables that accompany most centrifuges. If the par-
ticle density is unknown, a centrifuge speed of 2000 RPM-for ten minutes
for separating particles, and 10SQOO RPM for ten minutes for separating
emulsions is suggested. • •
The separation scheme has been applied to the wide variety of
wastes used in the development of the Teaching test. The wastes were
successfully separated into solid and liquid components, with the solid
components used subsequently in the leaching test. Use of unseparated
wastes in the leaching test would have been much more difficult than use
of solid components only, since many of the wastes were emulsion—solid
mixtures which would be very difficult to separate and could absorb
the leaching solution. If a solid-liquid separation is not performed
prior to the actual leaching test, most if not all of the difficulties
in performing such a separation are simply postponed to the point the
leachate must be separated from the remaining solids for analysis after
each elution. Thus, in addition to being more representative of land-
fill conditions, the separation also makes the leaching test easier to
perform.
32
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SECTION 6
INVESTIGATIONS AND DETERMINATION OF TEST CONDITIONS
Among the many test conditions and procedures which must be specified
in a standardized leaching procedure, certain ones were deemed of suffi-
cient importance to require specific investigations. They are listed below.
1. Leachate Composition
2. Solid-Liquid Ratio
3. Agitation Methods
4. Time per Elution
5. Number of Elutions
6. Temperature and Biological Aspects
These are discussed in order in the following sections for ease of presen-
tation. It should be noted, however, that the test conditions and proce-
dures are interdependent, and that laboratory work was not done to set one
condition, then another, etc. Work was performed regarding the various
conditions more or less simultaneously, with as many wastes as possible,
in order to accumulate the experience and evidence necessary to set rea-
sonable values or requirements for each.
Leaching Media Composition
A. Selection of Leaching Media
The original objective of this study was to quantify and model the
leaching situation occurring in sanitary landfills. Because of changing
leaching conditions as a result of decomposition process changes occurring
as a landfill ages, and because of the likelihood of wastes other than
municipal solid wastes being present in a landfill and affecting leaching
conditions for the waste being tested, it was felt necessary to consider
some of the extreme situations which could occur. If the subject waste
is landfilled with only municipal solid waste, it could be subject to
leaching media ranging in composition from leachate typical of young
{actively decomposing) to aged (stabilized) municipal waste sanitary
landfills. Further, depending on the relative amounts of the subject
waste and municipal solid waste, the leaching media will take on charac-
teristics ranging from municipal waste landfill leachate to leachate aris-
ing from the industrial waste itself, as in a monolandfill. Finally,
since many wastes are particularly susceptible to certain leaching condi-
tions (e.g., inorganic components are generally more readily leached -
under acidic pH conditions), and since wastes other than normal municipal
(residential and light commercial) solid wastes may be in a municipal
landfill as well, it was felt necessary to incorporate sufficient flexi-
bility in the leaching test procedure to examine the effect on leaching
of the subject waste of peculiar leaching conditions, as would be possible
if other industrial wastes would control leaching media composition.
33
-------
The extremes of the landfill situations discussed above are repre-
sented by monolandfills sanitary landfill, and industrial landfill situ-
ations, as shown in Table 5. The monolandfill situation describes 'land-
TABLE 5. LEACHING SOLUTION FOR VARIOUS TYPES OF LANDFILLS
Representative Landfill Situation Leaching Solution
Monolandfill Distilled, deionized water or leach-
ate produced from the waste
itself.
Sanitary landfill Municipal refuse sanitary landfill
leachate.
Industrial landfill Either a leachate based on the
characteristics of the wastes
in the landfill or a series
of leaching solutions as
described in the text.
filling of the waste in question by itself, or in a landfill where it
controls the leaching media composition either by being present in large
•amounts, or the municipal refuse being basically decomposed., An appro-
priate leaching media in this situation can be obtained by contact of
distilled water and the subject waste, by which the distilled water takes
on characteristics derived from the waste itself. Leaching media modeled
on actively decomposing municipal solid waste landfill leachate relates
to leaching of the industrial waste in an actively decomposing sanitary
landfill, where the municipal solid waste controls leachate composition.
Co-disposal with another industrial waste represents the extreme situa-
tion if the leachate characteristics are controlled by another waste,
whether it be in a so-called municipal waste sanitary landfill, or in
co-disposal in an industrial waste landfill. The leaching solution for
the industrial landfill could either be based on the composition of the
landfilled wastes and hence the leachate, if known, or consist of a
number of leaching solutions. The different leaching solutions would
emphasize a single leaching parameter—acid, base, complexing, etc. A
reasonable leaching media could also be obtained by contacting the other
wastes with distilled water, separating the spent waste, and using the
resulting leachate as the leaching media in contact with the waste under
study. If biodegradation is likely, a synthetic or laboratory-derived
leachate may be desired, similar to that which will be discussed for co-
disposal with municipal refuse. The results from the different leaching
34
-------
solutions would indicate with what other types of wastes the waste in
question could or could not be landfilled. Thus, a waste which releases
large amounts of an undesirable parameter under acid leaching conditions
should not be landfilled with an acid or acid-producing waste.
The emphasis of the remainder of this section is the development of
a municipal refuse sanitary landfill leachate, to model co-disposal of
the waste in question with municipal refuse.
B. Development of a Synthetic Municipal Landfill Leachate
To model the leaching occurring in municipal landfills, a synthetic
municipal landfill leachate (hereafter cal-led synthetic leachate) is
needed. The characteristics of municipal landfill leachate are such
that it cannot be modeled adequately by distilled water or by a simple
solution (e.g., 0.1 N acid). Rather, the aggressive characteristics of
the real municipal leachate need to be analyzed, and a synthetic leachate
modeling these characteristics developed. While it might be possible to
produce a real leachate in the laboratory, using municipal refuse and
water, the difficulty of producing reproducible solutions, the instabil-
ity of real leachate, and the high and often unstable background values
for many parameters of interest, favor the use of a more stable and
controlled synthetic leachate. The designation of a "standard" landfill,
from which a "standard" leachate could be obtained, is likewise unrealistic.
Unfortunately for the modeler, municipal landfill leacliates are
far from being homogeneous solutions. The pH can range from acidic (<4)
to basic (>8), while the measured ranges for many other parameters can
span six orders of magnitude or more. Obviously, one synthetic leachate
cannot model all municipal leachates. Since it is the aggressiveness of
the leachate that is of interest, it is reasonable to model leachates of
maximum aggressiveness.
The model development was as follows:
1. aggressive parameters in leachate were identified,
2. landfill degradation processes affecting these param-
eters were studied,
3. maximum measured concentrations of the parameters were
obtained from the literature and model compounds were
chosen,
4. the compounds were combined into a synthetic leachate at
concentrations based on the common maximum concentrations
in real leachate.
The maximum likely concentrations rather than the mean or weighted
average concentrations were used to give a reasonable worst case analy-
sis. In order to model the maximum Teachability of industrial wastes,
the chemical parameters in leachate representing the most aggressive
leaching media (e.g., low pH, low redox potential, high complexation
ability, etc) the waste would probably encounter were chosen. It is
necessary to keep this in mind when interpreting the results.
35
-------
(1) Aggressive parameters considered
Of the parameters judged to be of importance in bringing materials
into solution from solidss the following were chosen for consideration:
PH
complexing capacity
redox status
organic solvents
ionic strength
During the aging cycle of a landfill, these parameters will vary in
strength due to changes in the concentrations of materials producing
them. In order to understand and evaluate the variations found in the
parameters being considered for the synthetic leachate, some understand-
ing of the processes occurring in landfills is necessary.
(2) Theoretical degradation of a landfill
Imagine a hypothetical landfill with no external influences except
for a constant water input. As the landfill ages, a succession of stages
will occur.
Little or no leachate is produced until the landfill reaches field
capacity (becomes saturated with water). The composition of any leachate
produced prior to saturation, due to compaction and squeezing, will depend
on the composition of the water initially landfilled, and may vary greatly.
Three major bacterial processes primarily responsible for degrading
refuse are shown in Figure 11. Initially, aerobic decomposition pre-
dominates. This phase will generally be very short, given the limited
amount of oxygen in the landfill and the high BOD of the refuse. During
this phase, a large amount of heat is produced, raising the landfill
temperature well above ambient temperature.* Leachate produced during
this phase would be expected to dissolve very soluble salts (e.g., NaClt)
landfilled with the refuse.
As oxygen Is depleted, decomposition caused by facultative anaero-
bic bacteria will predominate. During this first stage of anaerobic
degradation, large amounts of volatile fatty acids (e.g., acetic acid)
and C0£ are produced. These acids reduce the pH to low as 4.5 to 5.
The low pH helps to solubilize inorganic materials which, along with the
high volatile acid concentrations, produce a high ionic strength (spe-
cific conductance). The high volatile acid concentrations also contribute
to the high CODs often found during this phase. The oxidation-reduction
potential (redox is reduced to below 0 mv (with respect to a Standard
Calomel Electrode).
*
Assuming an initial temprature high enough to start the dearadation
processes. One landfill, started during the winter, was found to be
still partially frozen over a year later.
36
-------
THEORETICAL DEGRADATION CURVES
H-
55
o
o
en
3
VOLATILE
ACIDS,
ppm
2 *
Z o
O -=
OXIDATION
REDUCTION
POTENTIAL. mV
CO
min. 4~5
max."-60%
~50% CH48CO
max. -viS.OOO ppm, ACETIC ACID
salts solubilized at low
PH
AEROBIC
PHASE
FIRST STAGE
ANAEROBIC
PHASE
solubilized by
decomposition
.-200
SECOND STAGE
ANAEROBIC DEGRADATION
TIME
Figure 11. Theoretical degradation curves of a theoretical
landfill.
37
-------
The second stage of anaerobic decomposition occurs when methane
producing bacteria complement the facultative anaerobes. Methane bac-
teria are strict anaerobes and require neutral pH levels. Volatile
acids produced by facultative anaerobes and other organic matter are
converted to methane and C0£. Thus, the volatile acid concentration
is reduced, and the gas composition becomes a mixture of CO;? and CH4.
With the neutral pH necessary for the bacteria to live, fewer inor-
ganic materials will be solubilized9 and specific conductance will fall.
The redox potential should be lower than the potential during the first
stage of anaerobic processes, reflecting the low potential needed for
methane production and the higher pH. Eventually, bacterial action may
decrease as the substrate is depleted and higher redox potentials may
be reestablished by oxygenated water.
(3) Actual degradation of a landfill
Environmental conditions may alter the theoretical degradation
pattern considerably. The amount of water input has a very important
effect on the rate of degradation. Obviously, the composition of the
refuse landfilled also has important effects as do landfilling practices
and seasonal variations in temperature. To complicate matters further,
different microenvironments in the landfill may undergo different stages
of decomposition at the same time. For example, Emcon Associates (5)
found high volatile acid production, low pH, and methane production
•occurring simultaneously. Since the low pH is toxic to the methane
producing bacteria, it is apparent that different areas of the landfill
had different and mutually exclusive conditions, with the leachate
reflecting both.
The data used in evaluating the parameters of interest came prima-
rily from the relatively few studies that have done detailed analysis
on leachate from a single landfill over a long time period (6-9), or
from work by Chian et al (10) relating leachate composition from dif-
ferent landfills to landfill age. Analysis of a single leachate sample
from a landfill was generally found not to be very useful, since the
concentration of a given parameter could not be related to the aging
process in the landfill.
Chian et al (10) analyzed several classes of organic compounds
and related variations in their concentrations to landfill age. Fig-
ure 12, based on their work, shows the variations of these classes as
a percentage of the total organic carbon with landfill age. The age
axis should be regarded as approximate, since landfill degradation
rates vary with environmental conditions. Their results will be dis-
cussed in the sections below dealing with the aggressive parameters.
a
38
-------
100
90-
80-
70
o
Ci
H
60-
50-
40-
20-
10-
CURVE KEY
I TOTAL % OF TOG IDENTIFIED
2 VOLATILE ACIDS
3 PROTEINS 8 AMINO ACIDS
4 CARBOHYDRATES
5 AROMATIC HYOROXYL COMPOUNDS
6 8 10
TIME, YEARS
14
1.6
Figure 12, The trends in the identified fractions of leachate TOC
vs. the age of the landfill. (From Reference (10).)
39
-------
(4) Maximum measured concentrations of the parameters
and model compound selection
-pH
There are two factors of importance in modeling pH and redox;
the measured value and the buffering capacity that maintains that value.
The buffering capacity indicates how resistant the measured value will
be to change. The minimum pH found in leachate comes during the period
of volatile acid production in first stage anaerobic decomposition,,
Chian et al (10) show that the pH and volatile acid trends in real
landfills follow the theoretical trends fairly closely. The pH com-
monly reaches four or five and is heavily buffered by volatile acids
Table 6 gives the pH ranges reported by various authors from their
TABLE 6. pH RANGES REPORTED BY VARIOUS AUTHORS FROM
LANDFILL OR LITERATURE SURVEYS
Source Range
Chian et al (10) 3.7 - 8.5
Steiner et al (11) 4.0 - 8.5
Clark et al (12) 1.5* - 9.5
Encom Associates (6) 3.0 - 8.5
Pohland (7) 4.9 - 8.4
*Site received acidic industrial wastes
literature reviews, while Table 7 gives the minimum pH values reported
in various studies. A pH of 4.5 was selected for the synthetic leach-
ate. As can be seen from Tables 6 and 79 a pH of 4.5 is not uncommon
in leachates. Furthermore, both C02 and volatile acid solutions achieve
maximum buffering capacity near this pH. An "average" landfill probably
does not maintain this low a pH for an extended period of time, but,
rather, maintains a pH of between 5 and 5.5. The emphasis here is leach-
ate aggressiveness, which warrants the use of the low pH value.
Relatively few investigators have studied volatile acid concentra-
tions in leachate. From the data available, given in Table 8, a value
of 300 mM (or 18,000 mg/1 as acetic acid) was selected as a reasonable
approximation for the highest concentrations commonly found in leachates.
Acetic acid is used as a representative volatile acid, since it is gen-
erally the acid in highest concentration in leachate during this stage
of landfill decomposition. Since the concern is with pH and buffering
capacity, use of a single acid to model the different volatile acids
poses no problem. The synthetic leachate contains 0.15 M acetic acid
and 0.15 M sodium acetate. The sodium is additionaly used in modeling
ionic strength.
40
-------
TABLE 7. MINIMUM pH VALUES FOUND IN LEACHATE STUDIES
Source
Emcon Associates (5,6) A
B
C
Qasim et al (9)
Fungaroli (8)
Pohland, Fill 1 (7)
Hughes et al (13)
U. IL* . •
Boon Co. *
Madison MUNC*
Madison UMC*
4.6
4.2
4.3
5.3
5.0
5.1
6.5
5.6
5.3
6.0
*From Chian et al (10). Single leachate sample.
TABLE 8. VOLATILE ACID CONCENTRATIONS FOUND IN LEACHATE
Concentration,
Landfill or Author fnMTT
Emcon Associates (5,6)
Cell A* 456
Cell B* 307
Cell C* 192
Pohland* (7) . 155
Madison, MUNC 300
Madison, UMCf 26
Boon County"1" 73
U. IL** 200
Burrows et al (14) 850*
*
Maximum.
'From Chian et al (10).
seems very high, especially since no acetic acid was found
found in the leachate.
41
-------
—complexation
Many different Ugands, both organic and inorganic, can complex
metals and leach them from industrial wastes. Organic compounds con-
taining nitrogen, oxygen, or sulfur in the proper configuration can be
very strong complexers. Data is available on the aging patterns of
aromatic hydroxyl groups in humic and fulvic acids and of N in proteins
and amino acids (Figure 12). Other complexing ligands may be of import-
ance in leachate, but the data available is not sufficient for modeling.
Humic and fulvic acids are general terms given to the heterogeneous
aromatic acids found in natural waters. They are often of high molecu-
lar weight and may contain N or S groups.• Since these materials are of
heterogeneous composition, they are. somewhat difficult to model with a
single compound. Chian et al (10) estimate that approximately 3% of the
TOC of leachates is in aromatic hydroxyl compounds (see Figure 12).
Based on the leachate data available, given in Table 9, a value for the
TABLE 9. CALCULATED CARBON CONCENTRATIONS OF AROMATIC
HYDROXYL COMPOUNDS FOUND IN LEACHATE
As 3% TQC, from Chian et al (10)
Sample (mMC)
MUNC 69.2
UMC 14.8
Boon County 34.6
U. IL 42.7
Calculated from Tannin and Lignin Data, Qasim et al (9)
Cyl. A 17.4
Cyl. B 33.8
Cyl. C 50.0
VALUE USED 50.0 mM C
42
-------
fulvic acid associated carbon of 0.05 M seems a reasonable approximation
of the fulvic and humic acid hydroxyl group concentration. The actual
concentration of the compound used to model these acids depends on the
carbon content of that compound.
Several aromatic hydroxyl compounds were tested as suitable com-
plexing agents. Tannic acid (C76H52046) and gallic acid (3,4,5-tri-
hydroxybenzoic acid) were found to precipitate with time. Pyrogallol
(1,2,3-trihydroxybenzene) was tried and was found to be an excellent
complexer, and a good reducing agent, as well. It is stable in solution
if kept from air contact. Other compounds were tried, including salicylic
acid, a-resorcylic acid (3,5-dihydroxybenzoic acid), benzoquinone, quinone,
and phthalic acid, but none were found to have the solubility and stabil-
ity in solution and the reducing capability of pyrogallol. Pyrogallol is
included in the synthetic leachate at 8mM.
The other complexing group being modeled is the amine group on
proteins and amino acids. Chian et al (10) found that a maximum per-
centage of the TOC as amino acids and proteins occurred early in the
life of the landfill (Figure 12). They ascribed this peak to single
amino acids. Glycine (H2NCH2C02H), the simplest of the amino acids,
was selected to model organic N in leachate. The concentration used,
50 mM, is based on organic N concentrations in leachate found by var-
ious researchers, which are given in Table 10. This assumes that all
the organic N is in amino acid form.
TABLE 10. ORGANIC NITROGREN CONCENTRATIONS
FOUND IN LEACHATE
Landfill Concentration, mM
Pohland (7), Fill 1
Fungaroli (8)
Emcon Assoc. (5,6)
A
B
C
Madison, MUNCt
Madison, UMCt
Boon Co.'f
U. ILf-
VALUE USED
12.6
15.0*
35.9
55.3
57.1
73.4
5.6
2.2
38.9
50.
*
Ignoring an initial peak.
"From Chian et al (10).
43
-------
—redox potential
Reactions controlling redox potential in leachate are not as well
understood as those controlling pH, and are correspondingly more diffi-
cult to model. Bacteria in the landfill and in the leachate itself play
a major role in controlling redox potential. Not only do bacterial proc-
esses in the landfill reduce the redox potential ofjthe leachate, but
bacteria in the leachate itself appear to maintain ^ low redox potential
in the leachate even after it is separated from the landfill. It was
found that the redox potential in unfiltered leachate would maintain a
steadier value when exposed to air than would filtered leachate, as
shown in Figure 13. Further, adding phenol to the unfiltered leachate
to inhibit or kill the bacteria caused the redox potential to rise
rapidly, paralleling the rise in the'unfiltered leafchate. Stirring
also had an effect. If the unfiltered leachate wer^ allowed to settle,
the redox potential in the supernatant rose. Upon stirring, the redox
potential fell to around its previous value. One plausible explanation
for this behavior is that the facultative anaerobes in the unfiltered
leachate remove any oxygen that enters the sample and, thus, maintain
anaerobic conditions. Killing microorganisms with phenol or allowing
them to settle out allows oxygen to enter and raise the redox potential.
In both filtered and unfiltered sampless a brown flocculant precipitate
was present, presumably an iron salt, indicating that the potential mea-
sured in both samples may not have been the potential found in the land-
fill.
Similarly to modeling pH, it is important not only to model the
redox potential itself, but also to model the redox buffering capacity.
While it is possible chemically to model redox potentials found in leach-
atess it is quite difficult to model the buffering capacity produced by
the bacteria. The ability of bacteria to maintain ja redox potential
when in contact with an industrial waste may be quite different from the
ability of a chemical redox couple to sustain the same redox potential.
Chian et al (10) predicted a redox potential between 0 and -200 mv for
leachate from a young landfill.
A pyrogallol - Fe2+ complex was selected to control redox potential
in the synthetic leachate. Pyrogallol is used also as a complexing agent
and, as such, its concentration is set at 8 mM. Ferrous iron was chosen
because it is a good redox control agent, especially when complexed with
the pyrogallol, is natural to leachates in high concentrations, and can
be used to model divalent cations. Other metals and complexing agents
2+ ' 2+
were tried as redox control agents, including Sn j Mn , ascorbic acid,
and the complexing agents mentioned previously. None of these gave the
2+
desired redox potentials in synthetic leachate. A Fe concentration of
24 mM was chosen to give a redox potential of -30 mV (vs SCE) at a pH of
4.5. Redox potential varies with pH, as shown in figure 14, and the
-30 mv quickly drops to lower values as the pH rises.
44
-------
_j 6 UNFILTERED, D FILTERED, A UNFILTERED-f-PHENOL
< — CHIAN S DE WALLS (10)
P 100
o
o
ui
oc,
X
o
-200
0 10' I02 I03
TIME, MINUTES
CHANGES IN OXIDATION-REDUCTION POTENTIAL
DURING STORAGE
Figure 13. Changes in the redox potential of leachate
during storage and after filtation.
45
-------
o--
o
O-
I
o
o-
CM
I
o
o-
ff)
I
o
o-
o
o-
o
o-
(0
1
o
?"
>
E
g
Q
SYNTHETIC LEACHATE
8-mM PYROGALLOL. 24 mM
@
©«
0 UNDER Nj
* UNDER N
-.
fc
no. 1
no. 2
©
III
©
A
©
£3'
A
A
32 mM PYROGALLOL. 96 mM
A UNDER AIR
H UNDER N«
A
A
A
EJ
A
PH
4.0
4.5
5.0
5.5
6.0
6.5
7.O
Figure 14. Change in synthetic leachate redox potential with pH.
46
-------
Redox potential modeling is both one of the more difficult aspects
of leachate to model and one that generates a lot of interest. The dif-
ficulty comes from tying to model a biological process chemically and
trying to use as simple a procedure as possible.
—organic solvents
Only limited data is available on the ability of leachate to solu-
bilize water-immiscible organic compounds. Burrows et al (14)5 Robert-
son et al (15), and Khare et al (16) have identified a number of organic
constituents in leachate of interest for modeling the organic solubilizing
capability. A summary of their data is given in Table 11. Unfortunately,
TABLE 11. ORGANIC COMPOUNDS OR CLASSES IDENTIFIED IN
LANDFILL LEACHATE
Author
Burrows & Row (14)
Khare & Dundero (16)
Robertson, Toussaint &
Jorqne (15)
Compounds
Acetone
short chain alcohols
short chain acids
Alkanes
Ketones (Acetone,
2-butanone)
CHC13, CC14
Aromatic solvents
(benzene, toluene,
xylene)
short chain alcohols
short chain amines
short chain acids
phthalate esters
Aromatic solvents
(cresol, xylene)
toluo ethyl-toluene
sulfonamide
alcohols
methylpyridine
ethers
short chain acids
Comments
leachate COD was 170,000 mg/a,
a very high value
Total carbon in leachate
was 767 mg/2,, a rela-
tively low value
very small percentage of
leachate T.O.C. identified
of these studies is useful for this modeling since none relate the various
jntrations to landfill aging processes. However, identification of a
none
concentrations
number of organic solvents in leachate indicates the need for further
research in order to determine the origins and concentrations of these
materials in leachates, and their change in concentration as the landfill ages.
47
-------
The majority of the known organic constituents in young leachate
have been modeled already in the other sections. Thuss the synthetic
leachate should provide a reasonable model for the organic solubilizing
capability of leachate until further data becomes available.
—ionic strength
Ionic strength may affect the leaching of materials in three ways:
by increasing the solubility through lowered activity coefficients, by
ion exchange processes replacing an ion bound to an ion exchange site
with one of the more predominant ions in solution, and by decreasing
the size of the double layer around colloidal particles and promoting
coagulation. • •
The ionic strength of leachate can be very high, but it is basically
2_
the result of only a few major species: Cl , HC03, SO. , and volatile
acid anions, and Na+, K+, NHj, Ca , Mg + , and Fe2+ cations. Values for
the maximum concentrations of these species reported in the literature
are given in Table 12.
Unfortunately, charge balances for these major ions for some of the
leachates reported in the literature indicate major charge inbalance-,
i.e., more plus charges than minus charges or vice versa. These calcula-
tions are shown in Table 13. While perfect charge balance would not be
expected due to analytical errors in measuring the many parameters used,
the magnitude of the difference in positive and negative charges indicates
that many ions, particularly anions, are not being accounted for. Pos-
sibly some of the differences are due to (a) ionized organic hydroxyl
groups, (b) association of some of the cations (particularly Fe) with OH
groups, (c) incorrect estimations of the percentage of the volatile acid
anions which are ionized, and (d) estimation of the HC03 concentration
from the bicarbonate alkalinity since some of the volatile acids are also
measured in the test for alkalinity. Whatever the reasons for the differ-
ences, it is important to keep in mind that knowledge of the composition
of leachate, both inorganic and organic, is incomplete. Our understand-
ing of the forms of the various parameters in the leachate is also, of
course, very hazy. Chi an et al (10) data presented in Table 13 was used
since these samples have been analyzed thoroughly for both organic and
inorganic constituents. Calculations using data from other researchers,
Emcon Associates (5) and Pohland (7), also show major charge inbalances,
with some positive and some negative residuals.
In modeling ionic strength, both sodium acetate-and ferrous sulfate
salts are used. The sodium, 150 mM, accounts for the ionic strength of
both sodium and potassium ions. The iron, 24 mM, models the divalent
cations. Its concentration is controlled by redox considerations and,
so, is somewhat lower than the concentration which would be used if
ionic strength alone dictated the concentration. The concentration of
the primary anion present, acetate, is controlled by the buffering con-
siderations for pH. Sulfate is added as the counter ion for iron.
48
-------
TABLE 12. CONCENTRATIONS OF THE COMMON INORGANIC
IONS FOUND IN LEACHATE
Source
Emeon Assoc. (5,6) A
B
C
Calif. Lab*
Calif. Fid*
Qasim et al (9)
Fungaroli (8)
Pohland (7), Fill 1
Hughes et al (13)
Stegmann (17)
Merzf
Meichtry
U. IL1"
Boon Co.
Mad. MUNCf
Mad. UMC1"
Value which could
be used
Na
39.1
74.3
41.3
78.5
30.9
62.6
165
7.8
52.2
109.3
78.5
33.3
59.1
32.6
68.7
14.3
100
K. •
23,4
41.2
21.6
47.6
4.9
96.4
20.2
61.4
47.6
1.7
29.2
22.0
58.8
23.0
50
Ca
56.0
74.8
42.4
64.3
8.9
101.7
31.3
7.5
8.4
64.1
180
93.5
58.0
97.5
14.3
100
Mg
mM
43.6
37.0
44.0
16.9
4.5
17.3
10.7
12.3
49.4
16.9
642
26.7
21.8
46.9
9.1
50
ca
117
113
36.6
66.2
24.4
65.1
56.3
10.8
43.3
106.6
66.2
18.6
41.7
59.0
69.5
13.4
100
S04
2.6
16.5
9.2
7.6
7.3
10.4
4.2
1.6
8.3
14.6
12.4
11.6
9.5
16.2
0.8
15
From Emcon Associates (6),
'From Chian et al (10).
49
-------
TABLE'13. CHARGE BALANCE CALCULATIONS FOR LEACHATE DATA
GIVEN BY CHIAN ET AL (10)
U.I. 2/1 MUNC UMC
mequiv/liter
Positive Ions
Na+
K*
NHj
Ca^
Mg4"*
Zn**
Fe**
Total Positive
Charge
Negative Ions
Volatile Acids
-Completely
Ionized*
-Using pKf
HOT/
SO"
Cl"
NO"
H2PO°
Total Negative Charge
Apparent Net Charge
59.1
29.2 .
28
187
53.4
3.2
78.8
438.7
(199.5)
159.6
5.7
23.2
41.7
0.0
0.2
231.4
207.3+
68.7
58.8
73.4
195
93.8
11.4
37.4
538.5
(300.1)
257.1
4.6
32.4
69.5
0.0
0.9
364.5
174.0+
14.3
23.0
20.4
28.6
18.2
0.0
3.2
107.7
(25.7)
20.6
2.8
1.6
13.4
0.0
2.7
41.1
66.6+
32.6
22.0
17.7
116.0
43.6
1.6
26.4
259.9
(73.4)
55.1
1.8
19.0
59.0
0.7
0.0
135.6
124.3+
*
Assuming all measured volatile acids are ionized. Value not used
in calculation.
Assuming partly ionized, in accordance with pKa values.
^Assuming all bicarbonate alkalinity as
50
-------
The complete composition and directions for the synthetic leachate
are given in Table 14. The Fe-Pyrogallol complex will oxidize and pre-
cipitate if exposed to air for very long. Therefore, experimental ves-
sels need to be either filled almost completely or purged with N£ before
sealing. Containers should be sealed tightly during experiments. For
long term experiments, glass containers should be used to avoid dif-
fusion of oxygen through the walls of the container. If kept from
oxidizing, the solution is stable for several weeks.
TABLE 14. DIRECTIONS FOR PREPARING THE SYNTHETIC LEACHATE
Composition:
0.15 M sodium acetate
0.15 M acetic acid
0.050 M glycine
0.008 M pyrogallol (1 ,2,3-trihydroxybenzene)
0.024 M ferrous sulfate
Directions:
I. Concentrated acetate buffer - glycine solution (10X)
Dissolve 204.1 gm NaC2H302- 3H20 and 37.5 gm glycine in
approximately 500 ml deaerated distilled water in a 1 liter
volumetric. Add 86.2 ml glacial acetic acid. Bring to room
temp, then dilute to volume. Solution is stable for at
least a week (probably more).
II. SL-A solution (synthetic leachate without the Fe)
Place 100 ml acetate-glycine solution in a 1 liter volumetric.
Add 1.05 gm pyrogallol and approximately 500 ml deaerated
water. After pyrogallol dissolves, bring to volume with deaer-
ated water. Prepare fresh daily and store in a stoppered bot-
tle or volumetric flask.
III. Synthetic leachate
Add 200 ml of SL-A solution to weighed waste in appropriate
flask. Add 1.38 gm FeS04 • 7H20 to solution, seal and shake.
If an amount of synthetic leachate other than 200 ml is
required, use 0.69 gm FeS04 • 7H20 per 100 ml.
51
-------
(5) Limitations of the synthetic leachate
There are two known limitations of the synthetic leachate (SL) as
presently formulated. First, the synthetic leachate is based on the
data currently available, this data being limited or nonexistent in some
areas. For example, data regarding organic solvents in leachate is very
limited. Many solvents have been found, as discussed previously, but
neither their concentrations nor their dynamics in the life cycle of the
landfill have been investigated. As another example, one might expect
some organic sulfur compounds to occur in leachate and to be very strong
complexing agents, but these compounds have not been measured in leach-
ate and, so, cannot be modeled. Second, the synthetic leachate does not
model the biota or particulate matter found in leachate. It is impos-
sible to model the diverse effects-of the bacteria chemically, and to
include bacteria in the synthetic leachate involves a much more com-
plicated and unstable leachate than was desired. Materials that will
leach from the waste in a landfill through sorption onto particulate
matter will not be leached by the synthetic leachate.
(6) A non-anaerobic modified synthetic leachate
The anaerobic nature of the synthetic leachate necessitates careful
handling of the leachate to minimize air contact. Oxidation of the
leachate results in the possibility of errors due to coprecipitation and
adsorption of the measured species on the precipitate. To avoid these
problems, a non-anaerobic synthetic leachate has been designed. Sali-
cylic acid (2-hydroxybenzoic acid) is used instead of pyrogallol as a
complexing agent, with the C content in the leachate from the complex-
ing agent at 0.05 M. Ferrous sulfate is left out. Otherwise the leach-
ate remains the same. The composition of the non-anaerobic leachate is
as follows:
0.15 M sodium acetate
0.15 M acetic acid
0.050 M glycine
0.007 M salicylic acid.
This is not as complete a model of municipal landfill leachate as
the anaerobic synthetic leachate, since it does not rcodel a significant
feature of municipal landfill leachate. It is, however, much easier to
use. The modified leachate has not been extensively tested, as has the
synthetic leachate, and is offered only as a suggested non-anaerobic
synthetic leachate.
52
-------
(7) Concluding statement
A synthetic leachate has been produced which is modeled after a
very aggressive municipal refuse landfill leachate. In order to verify
the leaching aggressiveness of the synthetic leachate towards industrial
wastes, it is necessary to use aggressive real leachate as a comparison.
Verification could be accomplished best by comparing the behavior of a
waste leached with the synthetic leachate with the behavior of the same
waste in an actively decomposing landfill.
The synthetic leachate provides a first generation model of aggress-
ive municipal leachate for use in a leaching test. Using the synthetic
leachate makes it possible to predict the waste constituents which would
dissolve in aggressive municipal leachate and, further, to estimate the
constituent concentrations which might be found in the real leachate.
Note that if the waste being tested is to be co-disposed with a biolog-
ically decomposable industrial waste, the synthetic leachate or a varia-
tion of it may be the best leaching media to simulate landfill conditions
Solid-Liquid Ratio
A. General Considerations
The solid-liquid ratio (waste/leachate) is very important in the
design of a standard leaching test. The ratio can determine whether or
not saturated conditions are reached and, if not, can affect the con-
centrations of the unsaturated parameters.
Two practical considerations are of importance. If the solid-liquid
ratio is very low, sampling and analytical errors will be magnified when
the release rate is normalized per gram of waste F^thermore the ""'
centrations of some interesting trace contaminants may fal below detec-
tion limits. At the other extreme, a very high ratio can lead to diffi
culties in stirring or separation techniques and can take a long time to
stabilize. Since landfills have high solid-liquid ratios over the short
term, the values chosen for testing were on the high solid-! qu d ratio
end of the spectrum when choices were necessary In most existing leach
ing tests the solid-liquid ratio is based on waste we ght anj J^u"Lf
volume or waste surface area-liquid volume ratios could be used. Surface
area is waste specific.
The solid-liquid ratio influences the results from a leaching test
and so should be standard for all wastes. If the solid-liquid ratio is
based on weight, the surface area-ljquid ratio then depends on the
specific weight of the waste. For two wastes with the same Article
size but ver? different specific gravities, e.g., lead and styrofoam,
the surface area of the lighter waste would be muc h 9^er in the test
if the solid-liquid ratio is based on weight. If the elution rate is
dependent on surface area, it would be more realistic to keep the waste
surface area-leachate volume ratio constant rather than the waste weight-
eachate volume ratio. Leaching will be controlled by surface area when
desorption and diffusion are the major factors controlling release, and
over the short term when solubility is ^controlling fac tor. It is
very difficult to determine when leaching is controlled by surfaces for
53
-------
different wastes. Also the surface area of a waste (e.g., styrofoam)
may change when the waste is landfilled, compressed by the weight of
overlaying wastes and decomposes. Original densities of the solid
portions of the different wastes used during the project are estimated
to have ranged from 0.8 to 2.5 gr/cm3. Therefore, the change in the
solid-liquid ratio, based on weight, would not have been expected to vary
over a factor of 2.5, if the surface area-leachate volume ratio was kept
constant. Unfortunately, it is very difficult to determine the surface
area of different kinds of wastes, especially if these wastes are
sludges, oils, or mixtures of different components.
In summary, the effect of using a constant waste surface area-
leachate ratio in a test rather than using a constant waste weight-
leachate ratio is difficult to predict, and to apply to a full size
landfill. Determination of surface area is difficult for many wastes.
Furthermore, for viscous liquids which are non-filterable and therefore
treated as solids in the test, surface area will depend on the shape of
the container. Therefore, in this project, solid-liquid ratios are
always based on weight.
In addition to simple solid-liquid ratios, two different landfill
situations were modeled and tested. These two situations, shown in
Figure 15, are as follows:
1. The landfill contains a very thick layer of waste, such that
a drop of liquid traveling through the waste will come in
contact with a large amount of waste (lower drawing).
2. The landfill contains only a thin layer of waste, such that a
drop of liquid traveling through the waste comes in contact
with only a small amount of waste (upper drawing).
Tests simulating Situation 1 will give values indicative of the maximum
concentration, while tests modeling Situation 2 will give an indication
of the maximum release of Teachable matter from a unit amount of waste.
B. Experimental Results and Discussion
Test Series V and R addressed the solid-liquid ratio effects and
modeled the different landfill situations described above. In Series V
distilled water was used as the leaching medium, with intermittent shaking
(further defined in the next section) as an agitation method. Each
elution lasted 24 hours, was run at room temperature, and was followed
by 0.45 micron filtration to separate the leachate and solids. The
different procedures within Series V are shown in Figure 16. Procedures
(tests) 6, 7, and 8 studied directly the effects of the solid-liquid
ratio. Three separate replicate flasks were set up at a given ratio,
with one flask removed for analysis daily. Three ratios based on weight
were tested, namely 1:10 (#6), 1:7 (#7), and 1:4.8 (#8).
54
-------
I 1 111
GROUND LINE
r••.'
sol
INDUSTRIAL
WASTE
LEACHATE
1 I i 1 1 1 i
GROUND LINE
DISTRIBUTION OF INDUSTRIAL WASTE IN
A MUNICIPAL LANDFILL
Figure 15. Landfill situations modelled in series V,
procedures 1 and 5.
55
-------
TEST SERIES V
TEST
NO.
i
3
4
§
DAY I
600 mL
1 «7
~8 6"g~ "~
600 mL
1: 2.3
257 g
600 mL
l;7
86 g
600 mL
1:7
86 g
200 mL
1:7
28.6 9
1
DAY 2
400 mL-
1 : 4.7
86 g*
400 mL
l;l.6
2S7 g
400 mL
_J'-±2 __
86 g
|
200 mut"
400 mL
1:7
86 g
200 mL1'
l:7
28.6 9
DAYS
200 mL
I. -2.3
86 fi*
200 mL
_h0.8
257 g
200 mL
1:2.3
86 g
200 mut
400mL
1:7
86 g
200 mu,1"
1:7
28.69
(
DAY 4
AFTER SAMPL
REMOVAL)
Til"™"
257 g
86 g
400 mL
86g
28.6 5
Figure 16. A diagram of test series V.
Fresh solids.
Fresh eluent.
56
-------
TEST SERIES V, CONTINUED
TEST
NO.
6
SAMPLE 1
200 mL
1:10
"~20~g~
DAT I —
2
200 mL
~20~g~"
3
200 mL
~20~"g
i Dfl
I
200 mL
1:10
"~2<5~g~
T
Z 1
2
200 mL
~20~g~
•DAY 3 ^
I
200 rnl.
1:10
2O g
200 mL
1:7
28.6 g
200 mL
28.6 g
200 mL
28.6 g
200 mL
1:7
28.6 g
200mL
23.6 g
200 mL
1:7
28.6 g
8
20OmL
1:4.8
42. 8g
200mL
42.8 g
200 mL
42. 8 g
200 mL
1:4.8
42.8 g
200 mL
42.8 g
20O mL
1:4.8
42.8 g
Figure 16. A diagram of test series V (continued).
57
-------
Landfill Situation 1, described above, was modeled in procedure
number 1. Initially, 86 gm of waste were mixed with 600 ml of eluent
(1:7 ratio). After 24 hours, the mixture was filtered, 200 ml of the
filtrate removed for analysis and the remaining 400 ml were mixed with
86 gm of fresh waste (1:4.7 ratio). The flask was again intermittently
shaken for 24 hours and the separation process repeated. 200 ml of the
filtrate were removed for analysis and the final 200 ml mixed with 86 gm
of fresh waste (1:2.3 ratio). The mixture was intermittently shaken
24 hours, then the final filtration was made. A total of 257 gm of waste
were used.
Procedures 2 and 3 were slight modifications of procedure 1. In
both cases, the filtered eluent was mixed with the same waste with which
it was initially contacted rather than replacing the waste each day.
257 gm of the waste were used in procedure 2, while in procedure 3,
86 gm were used.
Procedure 5 models landfill Situation 2 described above. Initially,
200 ml of distilled water were mixed with 28.6 gm of waste (1:7 ratio)
and intermittently shaken. After 24 hours, the mixture was filtered,
the filtrate analyzed and the solids returned to the flask. 200 ml of
fresh eluent were added and the mixture again intermittently shaken for
24 hours. After filtration, 200 ml of fresh eluent were again added to
the same waste sample. After 24 more hours, the sample was filtered
and the experiment ended. This procedure was determined to be the best
for foundry sand (Kunes, et al. 13)..
Procedure 4 is a cross between 3 and 5. It is similar to procedure
3, except that the 200 ml of solution removed for analysis were replaced
with fresh eluent, thus maintaining a constant solid-liquid ratio.
Representative results for Series V are presented in Figures 17,
18, and 19 in which paint waste (AA) was used. COD results are given
both as concentration and as the amount leached per unit mass of
waste. As can be seen from the results presented, the various proce-
dures (tests) used may influence the results. Redox and pH are par-
ticularly interesting parameters, since changes in these parameters may
affect the leaching of other parameters. The choice of procedure may
have an important effect on the leaching characteristics of the waste.
The results for COD (Figure 18) and Conductivity (Figure 19)
illustrate the information obtainable from the different tests. In
procedure 1, the COD concentration increases linearly, indicating
unsaturated conditions in the leachate. Procedure 5 shows that the
COD is not completely leached from the waste on the first day, since
subsequent elutions also have significant COD concentrations. Normal-
izing the COD release on a per weight basis shows that in procedure 1,
adding fresh waste does not change the COD released per kilogram of
waste, while the successive elutions in procedure 5 increase the release
per kilogram of waste. Procedures designed to give maximum concentra-
tions (#1) and maximum release (#5) are both important in a standard
leaching test; unfortunately, one test cannot give both. Data on the
maximum concentrations and maximum releases after three days for the
various wastes tested in Series V, including the paint waste, are given
in Table 15.
58
-------
pH
6.0
TEST NO.
SERIES V3 PAINT WASTE
PH
9.0-• 4——
8.0"
7.0
I I
6.0
TEST NO.
6 .—
7—-—
9.04 8— •
8.0- •
7.0-•
REDOX. mV
IOO--
50
O.
I 2 3
DAYS
,«,. REDOX. mV
I5OT
IOO--
50- -
O.
I 1
DAYS
Figure 17. pH and redox results from series V using paint waste.
59
-------
SERIES V3 PAINT WASTE
COD-
ppm
8000" 3 —-
6OOO- =
4000
2000- •
ppm
8000- • ^
6OOO
400O
2000-
TEST NO.
Gi -~™i —rf -jn.-r^,
30.0TE3 COD/kg PW
I5.O
0
DAYS
30.0
15.0
8 COO/kfl PW
i a 3
DAYS
Figure 18. COD results from series V using paint waste.
60
-------
SERIES V3, CONDUCTIVITY x 10 j^MHOS/CM
TEST NO. PAINT WASTE TEST N(X
^ _____ n
—._ 3
, A
.
5
6
______ •»
8
i.o -
.7 -
.4
o..
O.I -
.07 -
I.O
.7
.4--
.2--
0.1-
.07
•f-
•f
I 2
DAYS
I 2
DAYS
Figure 19. Specific conductance results from series V using paint waste.
-------
TABLE 15. MAXIMUM CONCENTRATIONS AND RELEASE
1.
cr>
Haste
Fly Ash (EPA)
Paper Mill Sludge (N)
Municipal Refuse
(City of Madison)
Paint Waste (AA)
Fly Ash
Test
Procedure
1
5
1
5
1
5
1
5
1
5
COD
[ppm]
-
61
7
1012
80
2990
160
8500
1090
875*
34*
Conduct.
x 10s
[pmhos/cm]
0.82
0.21
1.41
0.11
3.4
OJ35
0.67
.12
6.6
0.3
K
[ppm]
7
Oc
.5
6.6
2.0
190
2.8
108
.5
Ca
[ppm]
4.3
1.3
116
5.5
350
oc
£3
Fe
[ppm]
0.37
Q.12
11.0
0.2
Mg
[ppm]
150
8
58
3
Zn
[ppm]
5.7
0.32
0.84
0.19
After two days
-------
2.
TABLE 15 (continued)
Waste
Fly Ash (EPA)
o. Paper Mill Sludge (N)
Municipal Refuse
(City of Madison)
Paint Waste (AA)
Fly Ash
1
5
1
5
1
5
1
5
1
5
COD
[mg/kg]
105
259
1200
4000
5040
11190
12100
31500
2380
3000
K
[mg/kg]
18.4
21.7
13
51.3
289
513
138
199
Ca
[mg/kg]
7.3
27.4
175
296
671
1855
Fe
[mg/kg]
0.5
2 6
14.3
15.4
Mg
[mg/kg]
157
238
87
153
Zn
[mg/kg]
10.8
39.8
1 c
1 . D
51
. 1
-------
As might be expected, the COD concentration increases as the solid-
liquid ratio increases (#6 < #7 < #8), while the release per kg decreases
with increasing solid-liquid ratio.
In the following figures, the results from test series V are sum-
marized by chemical parameters (Figure 20—CODs Figure 21— Ks Figure 22
—Fe, Figure 23—Zn, Figure 24—Mg, Figure 25—Cu). The different curves
on each graph relate to the different wastes used:
#1 Fly Ash (EPA)
#2 Papermill Sludge (N)
#3 Paint Waste (AA)
#4 Fly Ash
#5 Shredded Municipal Waste (City of Madison)
The upper two graphs on each figure relate to the concentrations of
the various parameters, and the lower two graphs to the release of each
parameter per weight of waste. The two graphs on the left summarize
the results after one day for different solid-liquid ratios, and the
two graphs on the right for test procedures 1 and 5 after three days.
These are the two procedures suggested to best indicate maximum con-
centration (procedure 1) and release (procedure 5), and will be termed
Procedures C and R, respectively, for the remainder of this report.
These results suggest that all six chemical parameters measured
for the five wastes are influenced in a similar manner by variations
in the solid-liquid ratio. Concentrations decrease with decreasing
solid-liquid ratio while the quantity of release increases. The differ-
ences in results from test procedures #1 and #5 are noteworthy. This
summary shows that it is necessary to determine a standard solid-liquid
ratio for a standard leaching test. It also shows that the results from
procedures 1 (C) and 5 (R) are very different, and that determination of
both the maximum concentration and maximum release are important in
understanding the leaching characteristics of a specific waste.
Tests (procedures) 1, 3, 4, 5, and 7 in test series V all have
solid-liquid ratios of 1:7 on the first day, and concentrations would
be expected to be very similar for a given waste. Table 16 provides a
statistical evaluation of the test series V data, which shows that the
deviations from the means are generally small compared with the means,
indicating fairly good reproducibility. Some results are approaching
accurate detection limits for the analytical procedures used, and do
not relate so much to the reproducibility of the test procedure itself.
After performing these preliminary tests on the influence of the
solid-liquid ratio upon the Teachability of wastes, two more test series
(Rl and R2) were designed. In the first of these (Rl), the range of
solid-liquid ratios was larger than in series V (1:4, 1:2, 1:10, 1:20,
1:100), with waste weight measured as dry weight of the solids. This
was necessary because.the moisture content after the solid-liquid-
separation step will vary depending on the waste characteristics. For
example, a waste that has 90% moisture content will subject a smaller
amount of solids to the leaching media than a waste that has a 50%
moisture content, as shown in the following example.
64
-------
SERIES V, COD
LEGEND- VI •. V2 B, V3 A, V4 O. V5 V.
CONCENTRATION - I DAY, ppm CONCENTRATION - 3 DAYS, ppm
V3.V5
6250--1000
5OOO- -8OO
3750--600
2500--40O
I2SO- -200
VI.V2.V4
1 ^ f__
1-2.33 1-4.6 1-7
CUMULATIVE RELEASE-I DAY
V3.V5
25000- -3000
20 000- -2400
15000- -1800
10 OOO- -1200
5000
VI.V2.V4
600
V3.V5
10 OOO- -1000
80OO--800
6000 "SOO
4 000 "400
2000- • 200
VI.V2.V4
1-10
CUMULATIVE RELEASE-3 DAYS
V3.V5
37500--4250
30 000- -3400
2250O--2550
W I500O--I700
7 500- -800
VI.V2.V4
1-2.33 1-4.6 1-7 MO
SOLID-LIQUID RATIO
Figure 20. Summary of results from series V: COD.
65
-------
SERIES V, K
LEGEND" VI •. VtH, V4 O, V5
CONCENTRATION-! DAY, ppm
V4.V5
150° -7.5
120- -6.0
90- -4.5
60
30- -1.5
0
VI.V2
1-2.33 t-4.6
CUMULATIVE RELEASE-IDAT
V4.VS
8OO--4O
6QO
g 400 -
200- -10
VI.V2
30
1-10
CONCENTRATION-3 DAYS, ppm
V4.V5 VI.V2
200- -20
160
I2O
80- -8
40- -4
CUMULATIVE RELEASE-3 DAYS
V4.V5
500--5O.O
375- -37.3
2SO
0
VI.V2
2S.O
125- H2.S
I-2J3 1-4.6 I'7 MO
SOLID-LIQUID RATIO
I 5
TEST NO.
Figurt 21. Summary of results from series V: K.
66
-------
SERIES V, Fe
LEGEND- V2 •. V5 2.33 1-4.6
CUMULATIVE RELEASE-1 DAY
CUMULATIVE RELEASE-3 DAYS
1-2.33 1-4.6 1-7
SOLID- LIQUID RATIO
V5
16- -24
I2--I.S
w
V2
•-I.2
4--O.6
1-10
I 5
TEST NO.
Figure 22. Summary of results from series V: Fe.
67
-------
SERIES V, Zn
LEGEND- V3 A.V5
CONCENTRATION -I DAY, ppm
V5 V3
7.5--I.O
6.0
4.5 -•
V5
45
30.0- -6jO
J3» 22.5
+4.5
V3
7.5
IS.O- -3.O
7.5- 1.5
CONCENTRATION-3 DAYS, ppm
" V3
1-2.33 1-4.6 1-7 MO
CUMULATIVE RELEASE-1 DAY
0
CUMULATIVE RELEASE-3 DAYS
V5
375 • =7.5
3O.O-
o» 22.5 --4.5
a>
15.0'
7.5 -=1.5
V3
6.0
3.0
1-2.33 1-4.6 1-7 MO
SOLID-LIQUID RATIO
I 5
TEST NO.
Figure 23. Summary of results from series V: Zn.
68
-------
SERIES V, Mg
LEGEND- V2 B, VS V
CONCENTRATION- I DAY, ppm CONCENTRATION-3 DAYS, ppm
50T 200T
40
30--
2O--
10-•
1-2.33 I-4B l>7
CUMULATIVE RELEASE- I DAY
200T
160-•
120 --
1-10
o>
£ 80--
40--
CUMULATIVE RELEASE —3 DAYS
250T
200--
150- •
01
IOO--
50--
•f-
1*2.33 1-4.6 1-7 MO I !
SOLID • LIQUID RATIO TEST NO.
Figure 24. Summary of results from series V: Mg.
69
-------
SERIES V, Cu • V§
CONCENTRATION-1 DAY, ppm
I.O-r
0.8
0.6- •
0.4
0.2- =
O.OS
DETECTION LIMIT
1-2.33 1-4.6 1-7
CUMULATIVE RELEASE -I DAY
3.0-
2.25-
i
0.7S
0
I-1.33 I-4.6 1-7
SOLID-LIQUID RATIO
I'lO
CONCENTRATION-3 DAYS, ppm
1.0-
0.8
0.6- -
0.4--
0.2-
0.09+X
V
H
I
CUMULATIVE RELEASE-3DAYS
3.0-r
2.25- •
0.78+
0
I'lO
I 5
TEST NO.
Figure 25. Summary of results from series V: Cu.
70
-------
TABLE 16. STATISTICAL RESULTS FOR TEST SERIES V
FOR SOLID-LIQUID RATIO.OF 1:7 (WET WEIGHT)
AFTER ONE DAY
Eluent
Mg
Zn
Cu
Fe
K
COD
*Waste 1:
2:
3:
4:
5:
Waste* No. Samples
2
5
3
5
5
2
5
1
2
4
5
1
2
3
4
5
Fly Ash (EPA)
Paper-mill Sludge
Paint Waste (AA)
Fly Ash
Municipal Waste
j T 77* . ** *»
5
5
5
5
5
5
5
4
5
5
5
5
5
5
5
5
(N)
X S
18.6 2.3
23.2 14.9
0.274 0.025
2.76 0.47
0.298 0.047
0.124 0.0134
1.3 0.276
2.3 1.0
2.97 1.95
20.4 1.69
59.8 4.21
29.2 1.64
280 19.7
2390 192
362 42.8
1200 39.8
J - mean
S%
+12
+64
+ 9
+17
+16
+11
+21
+43
+66
+ 8
+ 7
+ 6
+ 7
+ 7
+12
+ 3
X + 2Sf
14, 23.2
-6.6, 53
0.22, 0.32
1.8, 3.7
0.2, 0.39
0.097, 0.15
0.75, 1.85
0.3, 4.3
-0.9, 6.9
17, 23.8
51.4, 68.2
25.9, 32.5
241, 320
2010, 2770
276, 448
1120, 1280
S = standard deviation
S% = standard deviation as
centage of X
a per-
In the interval X + 2S are
95% of all values (n = <-),
assuming values are normally
distributed.
71
-------
Assume the solid-liquid ratio is based on wet weight
and is 1:1.0. Also assume the spcific weight of the
solids is 1 kg/1 for two wastes, A and B, which dif-
fer in initial moisture content after filtration.
The amount of dry solids would be:
Moisture Wet weight of Dry weight of
Waste Content waste waste
100 ml leach- 100 ml leach-
ing solution ing solution
A 90% lOg lg
B 50% • lOg 5g
Therefore, the amount of solids used with waste B is
5 times higher than the amount used with waste A.
Initially, it was assumed that all wet wastes could be dewatered to
approximately the same moisture content, avoiding such problems.
Experience has indicated that this is not the case, and that dry weight
must be used.
Series Rl was performed with fly ash (particle size <0.5 mm) and
paint waste (AA). The procedure used was #5(R) from series V, where
the liquid is replaced every 24 hours to maximize release. Five elu-
tions were used. 0.1 N H2$04 and synthetic leachate were used as
leaching media. The composition and other characteristics of the
synthetic leachate were described in the previous chapter.
The influence of solid-liquid ratio on release after three days
can be seen from Figures 26 and 27. As seen previously (series V),
release generally is greater with lower solid-liquid ratios, although
some parameters do not show much influence over the range of ratios
1:4, 1:7, 1:10, and 1:20. Based on results for the series Rl, a 1:10
ratio based on dry weight appears reasonable. This ratio represents
a compromise which generally provides concentrations above detection
limits without the lower release of materials observed with the 1:7 and
1:4 ratios.
In the second test, series R2, the influence of the solid-liquid
ratio was tested again, but this time with test procedure 1 (C) of
series V, where the waste is replaced after each elution to maximize
the concentrations of leached substances. Three different ratios were
used: 1:5, 1:10, 1:20. Lower ratios were not tested because the objec-
tive of the test procedure was to achieve maximum concentration. Up to
five elutions were made in test series R2. The amount of waste that was
replaced each 24 hours was constant, but the leachate volume decreased
because samples were extracted for analysis after each elution. There-
fore, the solid-liquid ratio was not constant during the test. Table 17
shows the different solid-liquid ratios.
72
-------
SERIES R I, CUMULATIVE RELEASE-3 DAYS
Fe, ZgAg
»w.i.2Ti20 F.A.
K, Zg/kg
RW.0.7T7.0 KA.
Xrr—*—* *—
COD, Eg/kg
FA.I4-J-70P.W.
12- -60
O--SO
6- 3O
4- -20
2- IO
I I
1-4 1-7 MO 1-20
SOLID- LIQUID RATIO
MOO
Figure 26. Effect of solid-liquid ratio on
three-day Fe, K, and COD release.
73
-------
SERIES Rl, CUMULATIVE RELEASE - 3 DAYS
Zn.Smg /kg
PW 70O-J-35 F.A.
600- -30
5OO- '25
4OO- -20
30O- -IS
200- 10
10O--S
O.In HgSO,, SYNTHETIC LEACHATg
* FLY ASH m
& PAINT WASTE V
! mg/kg
Mg, 2mg/kg
P.W.35OT2800 F.A
>4 1-7 I»IO 1-20
SOLID • LIQUID RATIO
MOO
Figure 27. Effect of solid-liquid ratio on
three-day Zn, Nas and Mg release.
74
-------
TABLE 17. SOLID-LIQUID RATIOS DURING TEST SERIES R2
(BASED Of! DRY WEIGHT)
Elution Solid-liquid Ratios
1
2
3
4
5
1:10
1:8.5
1:6.9
1:5.4
1:3.8
1:5
1:4.2
1:3.5
1:2.7
1:1.9
1:20
1:17
1:12.8
1:10.4
1:7.6
The tests were performed with 0.1 N H2S04 and synthetic leachate
using fly ash (particle size<0.5 mm) and paint waste (AA) as solids.
In the case of fly ash the test could not be continued for 5 elutions
because of leachate loss due to absorption by fly ash and other losses.
In this case, when so many elutions were desired, fly ash should have
been wetted to field capacity with additional amounts of 0.1 N H2S04
or synthetic leachate.
pH and Na, Mg, and Fe concentration results for fly ash in 0.1 N
H2S04 from series R2 are presented in Figure 28. K, Cu, Pb, and Zn
concentration results are shown in Figure 29. Representative Zn con-
centration results using procedure R in series Rl from paint waste
using synthetic leachate are presented in Figures 30 and 31. Figure 30
provides more accurate representation of the results of the first few
elutions at the various solid-liquid ratios tested, whereas Figure 31
shows the data for more elutions at the 1:10 solid-liquid ratio. The
remaining results are in the Appendix.
The results from series R2 indicate that several parameters (Na,K)
reached their highest concentrations at the highest solid-liquid ratio.
Other parameters (Mg, Fe, Cu, Pb, Zn) display more complex leaching .
patterns and seem to be influenced by pH. The effect of fly ash solid-
liquid ratio on pH is shown in Figure 28. Fly ash neutralizes the acid
leachate, and increasing solid-liquid ratios of fly ash increases the
pH of the leachate. For a waste which influences the leachate pH, an
ideal solid-liquid ratio in a waste replacement procedure would be such
that the waste affects the leachate pH during the second or third elution
and comes to control pH by the end of the test. More information about
the leaching characteristics of such a waste is gained if this occurs.
For fly ash in 0.1 N H2S04, 1:10 or 1:20 are good solid-liquid ratios.
Figures 30 and 31 also indicate that higher solid-liquid ratios
result in higher concentrations of Zn, at least for this system, and
that this effect continues for several elutions. The low concentrations
achieved after 3 to 4 elutions were maintained for many additional
elutions for this waste-leaching media system, and continuing single
elutions over a longer period (over weekends in this case) had little
effect on concentrations obtained. Additional data and discussion on
elution time in initial elutions will be found in the section titled
Influence of Time per Elution.
75
-------
SERIES R2S FLY ASH
S/L RATIO'OI«5,AI'IO,DI'20, O.I n H2S04 LIQUID
pH Mg CONCENTRATION, ppm
10.0-
7.5--
§.©•
2.5- •
No CONCENTRATION, ppm
100-
80-•
60
40--
20'
Fe CONCENTRATION
60-r
4—f
2345
ELUTIONS
12345
ELUTIONS
Figure 28. pHs Mg, Nas Fe concentrations for different
elutions when fly ash is leached with 0.1N
HS0, series R2.
76
-------
SERIES R2, FLY ASH
S/L RATIO'01=5, AHO.G 1=20, O.ln H2S04 LIQUID
K CONCENTRATION, ppm Pb CONCENTRATION,ppm
200T
I50--
100-
50-1-
Cu CONCENTRATION, ppm
0.5T
0.37- •
0.25- •
0.12- •
Zn CONCENTRATION, ppm
8T
DETECTION
X
I I °
4—4—4
LIMIT'
12345
ELUTIONS
1234
ELUTIONS
Figure 29. K, Pb, Cu and Zn concentrations for different
elutions when fly ash is leached with 0.1N
HgSO^, series R2.
*A11 points below detection limits are approximate.
77
-------
Zn, ppm
21
SERIES Rl PAINT WASTE
SYNTHETIC LEACHATE
MARCH 22
Figure 30. Zinc concentration from paint waste leached
with synthetic leachate in series Rl for
different elutions. and at different solid-
liquid ratios.
78
-------
SERIES Rl PAINT WASTE
Zn, ppm SYNTHETIC LEACHATE
!2T A COINCIDENT VALUES
9"
3--
3/22 4/1 4/20 4/25 5/2 5/9 5/16 5/23
Figure 31. Zn concentration from paint waste leached with synthetic leachate in
Series Rl for more elutions at a 1:10 solid-liquid ratio (duplicate runs).
-------
Figure 32 shows the effect of solid liquid ratio on the Na and K
concentrations in the third elution leachates from fly ash and paint
waste using 0.1 N H2S04 and synthetic leachate. The dotted lines indi-
cate the concentrations expected if the concentrations were directly
dependent on solid-liquid ratio, using the concentration at a 1:10
solid-liquid ratio as a basis for calculation. In most cases the
experimental results at 1:5 and 1:20 solid-liquid ratios are close to
those calculated assuming a direct concentration dependence on solid-
liquid ratio, indicating that the concentrations are dependent on
solid-liquid ratio.
The results from all of the test series described in this chapter
show very clearly the value of using two different test procedures, such
as procedures 1 and 5 (C and R) from'series V. The importance of keep-
ing the solid-liquid ratio constant and relating it on a dry weight basis
for consistency is also shown. It is suggested that a solid-liquid ratio
of-1:10 (based on dry weight) be used for Procedures C and R (replacing
the waste and replacing the liquid, respectively) in the standard leach-
ing test. The quantity of waste that has to be replaced in Procedure C
should be enough to provide the ratios shown in Table 18. Of course,
the total quantity of leaching media and waste (ratio 1:10 initially
for both procedures) to be used will depend primarily on analytical sample
size requirements, but waste availability, and physical and equipment
limitations in the laboratory may also be important.
TABLE 18. SOLID-LIQUID RATIOS IN SUBSEQUENT ELUTIONS
FOR PROCEDURE C
Elution
1 l:10f
2 1:7.5
3 1:5
4* 1:2.5
*If required.
j,
'Based on dry weight.
Agitation Methods
In order to obtain uniform solid-liquid contact and representative
and reproducible results, a thorough but nondestructive agitation method
is needed. Ideally, the method would keep the waste suspended, yet not
cause abrasion of the waste particles.
80
-------
co
c
n>
CO
ro
-s -h to
01 O CD
O T3 (B
W O> l/>
ct- ro
w
pi ^
(/> O>
r*- X
(0 -<•
(u C
=J 3
O.
O
-h o
n>
3- -s
fa
O> rt
ri- -"•
O
< 3
O>
-J 0»
-i. -»,
O rt-
c n>
O 3-
—• ~i
a. ro
i
—• a.
-o'^c
C l/>
_J.
a.
CALCULATED VALUES FROM I«IO SOLID/LIQUID RATIO
K.ppm
160-t-
128-- R
96--
64--
32--
SERIES R2, MAXIMUM CONCENTRATION AFTER 3 DAYS
A A
a n
PAINT WASTE Na, ppm O.ln
100-r ||26
^
A O.I n H2S04
SYNTHETIC LEACHATE
80 -
60--
40-•
20--
-»
K, ppm
375-r
FLY ASH
A PAINT WASTE
B FLY ASH
l>5 MO l'20
SOLID/LIQUID RATIO
300--
225--
150-•
75--
-1
A O.ln H2S04
• SYNTHETIC LEACHATE
>5 NO I-2O
SOLID/LIQUID RATIO
^
1=5 J' 10 I =20
SOLID/LIQUID RATIO
-------
The influences of different agitation methods were tested in
series PV. Five agitation methods were used, selected on the basis
of ease of use, availability, and different agitation motions.
1. Continuous shaking (Gyrotory Shaker, New Brunswick Scientific
Co.).
2. Continuous mechanical paddle stirring (Phipps and Bird, Inc.,
Richmond, VA).
3. Intermittent shaking by hand,
4. Swing type shaking.
5. Rotating at two different angles.
Methods 4 and 5 will be discussed in detail later. For the first
group of tests (PV1-PV3), agitation methods 1, 2 and 3 were used. The
test procedure was that of Procedure R (replacing leaching media). For
each elution, 28.6 gm of waste were leached with 200 ml distilled water
for 24 hours. Intermittent shaking involves a brief, thorough shaking
of a 300 ml Erlmeyer flask by hand three times per day (morning, noon,
and late afternoon). Continuous shaking also involved use of a 300 ml
Erlmeyer flask, while continuous stirring used a 1000 ml beaker. In
both cases speeds sufficient to suspend most of the waste were used.
Typical results using paper-mill sludge (N) and municipal refuse
are presented in Figures 33 and 34. None of the first three agitation
methods gave consistently higher leaching rates than the other methods.
Stirring gave the highest Ca and Mg release from the papermill sludge and
the lowest Ca and Mg release from the municipal waste. With continuous
mechanical shaking, the Ca and Mg releases were the highest from the
municipal waste and lowest from the paper mill sludge.
Visual observations of the first three mixing methods tested in
series PV suggested that none of the three methods provided an optimal
solid-liquid contact. In the continuous shaker, the solids often re-
mained at the bottom of the flasks, particularly if a slow shake speed
was chosen. Higher speeds seemed to cause changes in the physical
properties of some wastes probably due to abrasion. Continuous mechanical
stirring may also have caused abrasion for certain of the wastes (i.e.,
papermill sludge and shredded refuse). Abrasion problems are expected
to be of even more concern with grannular materials, as has been expe-
rienced with foundry wastes (3). It was also observed that the waste
and the liquid tended to move at the same speed as the stirrer in the
continuously stirred flask, without optimal mixing.
These observations and the test results caused an examination of
other mixing procedures. A swing type shaker that moves slowly over a
small angle (approximately 180° every 30 seconds) was test in
PV4 and 5. A schematic of this unit is shown in Figure 35. Although
this mixer resembles the continuous shaking in the Gyrotory Shaker,
the basic idea of a swing type agitation method was- found to be worthy
of further testing. A machine was designed and constructed specifically
for this purpose.
82
-------
Mg
ppm
80-
SO
40-
20--
SERIES PV2, PAPER MILL SLUDGE
1500-r mg Mg /kg PMS
I20O--
900-
600--
300--
AGITATION
I SHAKE,INTERMIT, 20°C.
3 SHAKE, 20° C.
— . — 5 STIR
Co 8
ppm
6-.
2--
i 2
DAYS
120-r £ mg Co/kg PMS
SO--
SO--
I 2
DAYS
Figure 33.
The Ca and Mg results from series PV using papermill
sludge (N) and different agitation techniques.
83
-------
SERIES PV3, MUNICIPAL WASTE
2oo
ISO
120 ••
80
40-•
0
0
£mg Mg/kg M.W.
AGITATION, TEST NO.
I SHAKE. INTERMITTENTLY —
3 STIR
5 SHAKE, 20" C.
Co
ppm
30--
2O-•
10--
\
\
\\\
560 m9 Ca/
420
28Q-
\
\
\
\ 140
\
DAYS
DAYS
Figure 34. The Ca and Mg results from series PV using
municipal refuse and different agitation
techniques.
84
-------
180° SWING SHAKER
O • O SLOWLY
ROTATING DISK SHAKER
Figure 35. Diagram of the swing shaker and the rotating disc
device used in series PV.
85
-------
Another type of agitation method was also tested in series PV4.
This consisted of a rotating disk, which could be tilted at an angle
of 20° to 30° from the horizontal (Figure 35). Flasks holding the
samples and leaching media were mounted around the periphery of the disk.
In series PV4, a solid-liquid ratio of 1:10 based on dry weight
was used. Paper mill sludge (N), clarifier sludge (AA) from an auto-
mobile assembly plants paint waste (AA)S and fly ash (0 < 0.5 mm, AA)
were the wastes tested, and distilled water was used as the leaching
media. No major differences could be found in the results from the
three different agitation methods used. The results are presented in
the Appendix. The data were analyzed statistically, but no significant
differences between the test results with the three different agitation
methods could be found. The statistical tests wpre made at the 95%
confidence level. For example, the mean deviation was 5.75% comparing
intermittent with the swing-shaken and 1.41% comparing the intermittent
shaking to the rotated samples for the cumulative release of all mea-
sured parameters. By observing the mixing in the flasks moving on the
rotating disk, it was noted that no visible distinct mixing took place
under these conditions. The waste remained in clumps at the bottoms
of the flasks. Mixing in the swing-type shaker did not seem to provide
good mixing either. The solid often remained on the bottom and on the
side walls of the flask without real mixing.
It was possible to tilt the rotating disk such that the angle
against the horizontal was 90°. Watching the mixing process of different
wastes under these conditions, one noticed a good contact between solids
and the liquid especially when square bottles were employed. In round
flasks, the waste occasionally slid on the sidewalls and did not mix well.
In square bottles this effect did not take place. The rotating speed was
in the range of 2-5 rpm.
Vertical rotating disk mixing was tested together with intermittent
and swing-shaking (Figure 35) in test series PV5. The same wastes used
in series PV4 were used along with shredded refuse from the city of
Madison. The procedure was identical with that of series PV4. Square
plastic bottles were used in the rotating machine. The liquid in the
flasks was 0.1 N ^SO^, in order to have a very aggressive leachate, so
that eventual differences in the test results could be more readily
detected.
Another device tested in this test series was a pressure release
valve. During the leaching process, gas production may occur. In order
to release the pressure which could damage the flasks or cause leakage,
pressure release valves were installed which opened when the pressure in
the flask exceeded 1 psi. These were essentially spring loaded ball
release valves, with adjustable spring compression. As long as the
solid-liquid mixture did not contact the valve, the valve would function
properly. If contact was made, the liquid could interfere with the
operation of the valve. With the wastes tested, of which the municipal
refuse could be considered prone to biological activity, gas production
sufficient to warrant the release valve was not observed. Even if a
86
-------
small amount of gas production is anticipated with a particularly biolog-
ically active waste, pressure relief valves or frequent manual venting
should be used.
The results from series PV5 can also be found in the Appendix. A
statistical analysis of the results comparing intermittent and swing-
shaking indicates that the cumulative release from all wastes and all
parameters measured was 10.9% higher using the swing-shaking procedure.
This is at the 95% confidence level. If the agitation procedures of
intermittent shaking and rotating are compared, the cumulative release
after three days was significantly higher using the rotator (23% more
release).
The results from the series PV -show that the different agitation
methods provide nearly equal release, but that the rotator seemed to be
the most effective agitation method, both from visual observations with
different wastes, and from somewhat higher release figures. Equipment
capable of doing this is commercially available* for a reasonable price,
and different rotator heads are available so that different kinds of
flasks may be used. The motor did not overheat even after many days of
operation. The rotating speed can be varied, but a speed of 3.5 rpm
was used for this study. The rotator head should be balanced when per-
forming these tests. The angle of incline of the disk or head is adjust-
able; the angle of the circle of rotation to the horizontal was set at
approximately 70° for this research. Visual observations should be used
to set the angle and speed so wastes are mixed and turned to provide
good media-waste contact without causing any more abrasion than necessary.
Influence of Time per Elution (Series PI)
Fly ash with a particle size smaller than 0.5 mm and paint waste (AA)
were used in series PI to investigate the influence of reaction time on
the rest results. Three elutions of various durations were used. After
each elution, the liquid was filtered for analysis, and the waste was
contacted with fresh leachate (Procedure R). Three different leachates
were used: 0.1 N ^$04, synthetic leachate, and distilled water. The
following reaction times were used for each elution: 2 hours, 24 hours,
48 hours, and 72 hours.
The cumulative release after 3 elutions for each parameter is plot-
ted in Figures 36 and 37. There is no consistent trend in cumulative
release after 3 elutions with respect to reaction time. In particular,
there was an increase in cumulative release with reaction time for the
test with fly ash in 0.1 N H2S04- This tendency is obvious for K, Mg,
and Fe. In this case, it is possible that parts of the fly ash are
dissolved more readily by the acid with increasing reaction time, which
suggests that the fly ash may change its composition and pore size during
*
Such as the Rugged Rotator, model RD-250, manufactured by Kraft
Apparatus, Inc., of Mineola, New York, as used in this study.
87
-------
SERIES PL CUMULATIVE RELEASE AFTER 3 ELUTIONS
oo
00
COD, £mg/kf) K, £mg/k$
2500
2000
1500
1000
500
0
60000
45000
30000
15000
0
^ —• — • 750,
/ \ LEGEND
j/ \ PAINT WASTE •
\ FLY ASH • goo
• DISTILLED H20
SYNTHETIC LEACHATE 450
O.I N H2S04
— — — — — JQQ
• |5()
.x- X.
• s.
'" No, Img/kg
A
/ \ 500
/ \
/ A. \ .-•• 375
/ / x **""
/ ~~""~* 25O
/
*
125
iii i « 0
^"^ 60.0
S
^r^*"^ -« 375-
^^^^•vT ^
^ / ~~~* 25.0
j
12.5
,„ i .,«., — i 1 0
^f
J*"
f^^
1
/
^*~*-^*
^*~
10- p
*"^*~~~O •••• ffii
B
A /
/ 'x- -/
/ \
*/ 'V--
/ A v
/ =x* — ^.
/ ^
— « — _« — — i — — — «
24 48 72
2 24 48 72
REACTION TIMES, HRS
2 24 48 72
Figure 36. Cumulative release after three elutions for series PI (COD9 Nas 1} for
different reaction times.
-------
CO
10
Mg. Img/kg
500
SERIES PI. CUMULATIVE RELEASE AFTER 3 ELUTIONS
LEGEND-tPAINT WASTE, • FLY ASH, DBTjLLrajl^ SYNTHETIC LEACHATE. OJNjfeS^
Emg/kg Zn. Emg/kg
400
300
200
100
V
24 48 72
3000.
2250
1500
750
I60
120
8°
40-
s
/
A
\
\
v
200
ISO
K)0
50
Zn,£mg/k9
2 24 48 72
REACTION TIMES, HRS
24 48 72
Figure 37. Cumulative release after three elutions for series PI (Mg, Fe, Zn) for different
reaction times.
-------
the test. This does not happen to the same degree when distilled water
and synthetic leachate are used. With the paint waste, the cumulative
release is more independent of elution time.
In practically all cases with both wastes, the cumulative release
is lower with a two-hour reaction time, suggesting the use of a longer
time. For reaction times 24 hours or greater, the cumulative release
is varied—sometimes rising, sometimes falling—indicating that the
effect of reaction times greater than 24 hours are not consistent.
Therefore, selection of a leaching time within this 24-72 hour range
should be made on factors other than approach to equilibrium conditions,
since these systems do not appear to be in equilibrium within this time
frame.
A 24-hour elution time is normally convenient for laboratory organ-
ization and personnel. Since 3 elutions are required by this test, an
elution time of 48 hours would make the total test 144 hours long and
would necessitate weekend laboratory activity. Also 48-hour or 72-hour
elutions would introduce greater possibility of biological effects in the
test system. If higher leaching rates are desired, it is more effective
to use more elutions of 24 hours reaction time each than to have a longer
reaction time with fewer elutions. (Note that the number of elutions
and the total test time will be discussed later.)
Influence of Number of Elutions
Ideally, a test should run until no further material leaches out
of the waste. This is not practical because small amounts of material
may leach from a waste for years.
The number of elutions required to establish release patterns is a
function of the test procedure (i.e., Procedures R or C), the solid-
liquid ratio, the kind of eluent used, agitation method, the length of
each elution, etc. From previous sections, information is available
to set reasonable values for these test variables so the influence of
the number of elutions can now be evaluated.
Test series Rl was run to investigate the influence of the solid-
liquid ratio and the number of elutions on the results of the leaching
test. Portions of these results were cited previously in the section
on solid-liquid ratio. In this test series, Procedure C was used for
fly ash (AA) and paint waste (AA). This procedure uses a solid-liquid
ratio of 1:10 on a dry weight basis, and the waste is replaced for suc-
cessive elutions. A total of 31 elutions over a 14-week period were made.
The first 21 elutions, done in 4 weeks, used an elution time of 24 hours,
except on weekends when a 72-hour elution was performed. For elutions
after the 21st, the elution time was extended to one week. Longer elution
times were used to reduce the number of samples and yet retain a long test
duration. The results from test series R are presented in the Appendix.
90
-------
Two examples of the results are shown in Figures 38 through 41 to
illustrate the results that were obtained. Figures 38 and 40 provide
results for the solid-liquid ratios tested for the first few elutions.
Figures 39 and 41 show the results at a solid-liquid ratio of 1:10 over
more elutions. Figures 38 and 39 indicate that the release of Fe from
fly ash by using 0.1 N H2S04 takes a long time. The release pattern
suggests that fly ash is not a uniform waste. The increase of the Fe
concentrations after 3 elutions is difficult to explain, because this
did not occur when solid-liquid ratios other than 1:10 were used. On
the other hand, the test at a 1:10 ratio was performed in duplicate and
the results were the same in both. In Figures 40 and 41, the results
for Zn indicate that for paint waste and 0.1 N H2S04, a steady state is
reached after three or four elutions. For the fly ash, a more complex
.release pattern is indicated.
An evaluation of the percentage of the total release found by each
elution was made intfie following manner. First, the number of elutions
needed to reach steady state conditions was determined. Steady state
conditions were assumed to exist when the concentration stooped falling
and maintained a relatively stable level (see Figure 42). The total
release up to the time when steady state conditions were reached was
calculated, and the percentage of the total released by each elution
determined. In cases where steady state conditions were not reached,
total release at the end of the test was used at 100%. The percentage
released by each elution for series Rl is shown in Figures 43 and 44.
As seen in Figures 43 and 44, some parameters (e.g., Zn in paint
waste) approach 100% release within a few elutions, while others (e.g.,
Fe in fly ash) release very slowly. Therefore, the ideal number of
elutions varies with the parameter observed. In two cases (Fe and K
from fly ash in 0.1 N 82804), steady state (basic) conditions were not
reached by the end of the test. Percentage cumulative release curves are
either straight lines or have decreasing slope with increasing elution
numbers. The fastest release, which corresponds to the steepest slope,
occurs in the first test elutions.
In Table 19 the results from test series Rl are summarized. Cumu-
lative release from elutions before steady state values are reached is
compared with the total release after 28 elutions (11 weeks). The
results indicate that before the steady state values are reached, the
cumulative release as a percentage of the total release over the whole
test period, varies between 40 and 100%.
The total release from series Rl after 11 weeks (28 elutions) was
also compared with the results from total digestion of the fly ash.
Although it was not possible to dissolve completely all solids (residue
~l-5%), the total release after 28 elutions was relatively low compared
with the amount of each component in the original fly ash. The results
are presented in Table 20. The total release from the fly ash was
higher when 0.1 N H2S04 was used in the leaching test.
91
-------
ppm
/
SERIES Rl FLY ASH
O.I N. H2S04
• I-100 * h!0
» l« 20 * |i 7
* l« 10' ' x l« 4 /
/ X*
/ /
/ /
/
MARCH 22
Figure 38. Fe concentrations from long-term leaching
experiments in series Rl with fly ash and
0.1N H^SCK at various solid-liquid ratios,
92
-------
Fe, ppm
2400-r
2000--
I600--
1200--
800--
400--
.:•
SERIES Rl FLY ASH
o.i N H2S04
SOLID-LIQUID RATIO I'10
& COINCIDENT VALUES
111 IN mill III II II III I HUM I
A
h
3/22
4/1
4/20 4/25 5/2 5/9 5/16 5/23
Figure 39. Fe concentrations from long-term leaching experiments in series Rl with fly ash
at solid-liquid ratio of 1:10 (long-term results, duplicate runs).
-------
FLY ASH
0.0184=
MARCH 22
Figure 40. In concentrations from long-term leaching
experiments in series R1 with fly ash and
0.1N H2S04 at various solid-liquid ratios.
94
-------
UD
en
Zn, ppm
2.0 T
1.6
1.2 -
0.8--
0.4--
SERIES Rl FLY ASH
O.I N
SOLID -LIQUID RATIO I- 10
A COINCIDENT VALUES
VALUES < 0.018 ppm
« mA»AA A
ll mill 18 ll ITTTTTIITTTTTIITTT t-
I
4-
3/22
4/1
4/20 4/25 5/2
5/9
5/16
5/23
Figure 41. Zn concentrations from long-term leaching experiments in series Rl with
fly ash at solid-liquid ratio of 1:10 (long-term results, duplicate runs).
-------
cumulative release
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I
2
2
3
3
4
4
567
789
BASIC CONCENTRATION REACHED
* COD (I) I2E/I6DAYS
OCOD(2) I2E/I6DAYS
v Fe (I) P.W..A
V Fe (2) 22E/30DAYS FLY ASH, A
•t-Zn(l) 9E/IIDAYS FLY ASH, A
QZn(2) 6E/8DAYS FLY ASH, SL
A Zn(3) 6E/8DAYS P.W..A
D Zn(4) 7E/9 DAYS P.W., SL
NO BASIC CONCENTRATION
REACHED
P.W. PAINT WASTE
A O.ln H2S04
SL SYNTHETIC LEACHATE
E ELUTIONS
8 9 ELUTIONS
10 II DAYS
Figure 43. Cumulative release as a percentage of the basic or steady state concentration
for various parameters leached from paint waste and fly ash in series Rl.
*Basic concentration equals steady state or end of test concentration, as defined in Figure 42.
-------
00
100 T
80--
60
8
DC
111
40 -
20--
•i h-H
BASIC CONCENTRATION REACHED
K (I) -— FLY ASH, A
K(2) 9E/IIDAYS FLY ASH, SL
K(3) HE/I5 DAYS P.W..A
K(4) 8E/10 DAYS P.W., SL
Mg(l) 82E/I6 DAYS FLY ASH, A
Mg(2) 7E/9 DAYS FLY ASH, SL
Mg(3) 3E/3 DAYS P.W., A
Mg(4) 5E/7DAYS P.W., SL
NO BASIC CONCENTRATION
REACHED
PAINT WASTE
O.ln H2S04
SYNTHETIC LEACHATE
ELUTIONS
4-H
23456789 ELUTIONS
2 347 8 9 10 It DAYS
Figure 44. Cumulative release as a percentage of the basic or steady state concentration for
various parameters leached from paint waste and fly ash in series Rl (continued).
Basic concentration equals steady state or end of test concentration, as defined in Figure 42.
-------
TABLE 19. COMPARISON OF THE CUMULATIVE RELEASE WHEN STABLE LEVELS ARE REACHED TO THE
CUMULATIVE RELEASE AFTER A TEST PERIOD OF 11 WEEKS (28 ELUTIOfIS) IN PERCENT
IO
Parameter
COD
COD
Na
Na
Mg
Mg
Mg
Mg
K
K
K
K
Fe
Fe
Zn
Zn
Zn
Zn
Eluent
0.1 N H2S04
0.1 N H2S04
0.1 N H2S04
0.1 N H9SO.
i 4
0.1 N H2S04
Synth. Leach.
0.1 N H2S04
Synth. Leach.
0.1 N H2S04
Synth. Leach.
0.1 N H2S04
Synth. Leach.
0.1 N H2S04
0.1 N H2S04
0.1 N H2S04
Synth. Leach.
0.1 N H2S04
Synth. Leach.
Waste
Fly Ash
Paint Waste
Fly Ash
Paint Waste
Fly Ash
Fly Ash
Paint Waste
Paint Waste
Fly Ash
Paint Waste
Fly Ash
Paint Waste
Fly Ash
Paint Waste
Fly Ash
Paint Waste
Fly Ash
Paint Waste
No. of elutions (days) Release when stable levels
to reach stable levels attained as a percentage of
total cumulative release
Elutions Days after 11 weeks (28 elutions)
12
12
not reached
9
12
7
3
5
not reached
9
11
8
not reached
8
9
6
6
7
16
16
11
16
9
3
7
11
15
10
11
11
8
8
9
72.8%
87%
40.5%
69.8%
51.6%
; 100%
78.8%
46.2%
63.7%
46.9%
41.8%
79.2%
70%
98.6%
83.4%
-------
CD
O
TABLE 20. CALCULATION OF THE RELEASE AFTER 28 ELUTIONS (11 WEEKS) AS.A PERCENTAGE
OF THE AMOUNT OBTAINED BY TOTAL DIGESTION OF FLY ASH
Percentage of Dry
Weight of Differ- Absolute Content in
ent Parameters in 25 gm Fly Ash
Fly Ash* (mg)
Na =
K =
Pb =
Fe =
Mg =
Cu =
Zn =
Total
18.5% 4625
1 . 54% 385
0.12% 30
8.66% 2165
0.51% 127.5
0.03% 7-5
0.047% 11.75
29.4%
Cumulative Release
[mg/25 gm]
Over Test Period
(11 weeks)
(1)
.(1)
(2)
(1)
(1)
(2)
(1)
(2)
3.22
6.59
1.13
150.11
1.63
0.52
0.025
0.024
Percentage Release
After 11 Weeks and
28 Elutions
0.07%
1.71%
0.29%
6.93%
1.28%
0.41%
0.21%
0.20%
(1) 0.1 N H2S04
(2) Synthetic leachate.
*Measured after total digestion according to procedure specially developed for fly ash digestion
-------
The results indicate that with some wastes, elution at steady state
conditions may continue over a very long time period or that portions
of the chemical constituents are not Teachable (i.e., bound in the par-
ticles and not available for leaching). It is clear, at leas't for the
wastes tested, that total release is not a realistic goal for any
reasonable leaching test. A complete digestion procedure, if available,
would not relate to landfill practice unless the particular waste in
question does in fact dissolve or decompose completely in the landfill.
Conversely, more elutions than 3 to 5 were found in previous results
to provide little or no additional information unless complete long-term
leaching procedures are the alternative.
It is clear that there is no ideal number of elutions for all param-
eters in all wastes. Three elutions wer£ 'chosen for the S.L.T. on the
basis of convenience and lack of data suggesting otherwise. Tests can
be started on Monday, elutions finished by Thursday and analytical work
done on Friday. Four elutions could also be used without inconvenience.
Steady state concentrations reached after a large number of elutions are
typically low and are influenced by the background values of the leachate.
Also steady state concentrations are often near parameter detection limits
and analytical errors increase.
If the results from 3 elutions indicate continuing release at about
the same rates, additional elutions might be performed, but the results
must be clearly marked as being from more than 3 elutions and must be
interpreted accordingly. Continuing release probably indicates that
the waste is dissolving or breaking down, and that eventually those
chemical species being leached will be released entirely to the leaching
media. In such a case, a complete analysis, such as would be obtained
by digestion, for example, might be useful.
Influence of Temperature and Biological Aspects
Temperature will have an effect on leaching test results due to its
effect on chemical and biological reactions. Two tests, PV2 and PV3,
which were presented earlier in the discussion on agitation methods,
also examined temperature effects at 20°C and 33°C. Results beyond
those presented in the earlier section can be found in the Appendix.
Statistical evaluation of the results indicates that the variation due
to the 13°C temperature difference was approximately the same as the
variation due to analytical error. In one case (PV2), the deviation
due to temperature was 15.1% lower than that due to analytical error,
while in the other case (PV3), the deviation due to temperature was 6.7%
higher. It is concluded that for the wastes tested, and over the narrow
but realistic temperature range tested, the influence of temperature
was not important. Neverthless, it is obvious that laboratory tempera-
tures should be used as a standard, and unusual test temperatures be
documented and reported. Such might be the case, for example, if the
waste in question is being landfilled under unusual temperature condi-
tions.
101
-------
Two types of tests were conducted to examine biological aspects of
leaching an industrial waste.
The first biochemical test was a toxieity test to determine the
toxicity of the waste to methane producing bacteria, such as would be
found in an actively decomposing sanitary landfill. A diagram of the
apparatus used for the toxicity test is shown in Figure 45. The gas
volume was measured by the displacement of water in the plastic column
shown in Figure 45. The column on the right is used for pressure adjust-
ment.
The industrial waste was mixed with an active culture of methane
producing bacteria in a shredded refuse—sewage sludge slurry (Refuse +
refuse water to sludge weight ratio' of 2:1 )9 incubated at 33°C and the
resulting methane volume produced compared with the volume produced
from an industrial waste-free mixture. A typical gas production curve
from the municipal refuse-sludge mixture is shown in Figure 46, where the
gas production indicates a lack of toxic effects for this waste mixture.
Should another waste prove toxic to the methane producing bacteria in the
test, it would probably also be toxic to the bacterial populations in a
sanitary landfill, and might be better disposed in another type of land-
fill (assuming decomposition is not to be inhibited).
The second biochemical test was a comparison of the leaching char-
acteristics of Madison municipal refuse when leached with distilled
water and distilled water with bacteria inhibiting agents added.
Unfortunately, most bacteria inhibiting agents directly affect the leach-
ing properties of the eluent. Three inhibiting agents—AgNOa, CuS04 and
thymol—were used in separate tests. Test results that are similar in
all inhibited leachates but vary between inhibited and distilled water
leachates can be considered to reflect bacterial inhibition. Test
results that vary between the three inhibited leachates probably reflect
the effects of the inhibiting agents.
Tests B2 and 83 used a solid-liquid ratio of 1:7 based on wet
weight and Procedure R (new leaching media for each elution). The
moisture content of the refuse was approximately 50%. B2 was run at
room temperature for three days, while B3 was run at 33°C for seven
days. The bacterial inhibiting agents were added at the following
concentrations:
AgN03 1.0 g/1
Thymol 1.5 g/1
CuS04 1.5 g/1
In Test B3, it was possible to qualitatively assess anaerobic biological
processes by smell. Only the distilled water leachate had the volatile
organic acid smell typical of anaerobic processes.
102
-------
ANAEROBIC
CONDITIONS
COMPRESSED
GAS
MIXTURE OF—^
MILLED REFUSE
AND WATER
.-'
,VE«T
PLASTIC
AEROBIC CONDITION
MIXTURE OF
MILLED
REFUSE AND
WATER-
COMPRESSOR
Figure 45. A diagram of the toxicity test apparatus,
*Equa1ize water levels during gas volume measurement.
103
-------
o
gtEGAS PRODUCTION,mt GAS PRODUCTION, ANAEROBIC DIGESTER
o
6 7 8 9 10
TIME, DAYS
12 S3 94 15 86
Figure 46. The volume of methane produced versus time by a municipal refuse-
sewage sludge slurry.
-------
The last test for determining biological influences was 84. Here
Procedure C was used (new waste for each elution)with the shredded
refuse being replaced two times. The solid-liquid ratio was 1:10 based
on dry weight. The consentrations of the bacterial inhibiting agents
were 10 g/1 for all agents. At the conclusion of each elution, 200 mis
of the filtered leachate was removed for analysis.
A summary of the cumulative release from test B2 and the maximum
concentrations in tests B3 and B4 are shown in Figures 47 and 48. Com-
plete results are given in the Appendix. As can be seen from the figures,
there is no consistent effect of the bacterial inhibiting agents on the
test results. This indicates that any effects of bacteria on the leach-
ing characteristics of the waste are less than the effects of the bacterial
inhibiting agents or of random test variations. Apparently within the
time span of the leaching tests used, bacterial action did not show an
overwhelming effect on leaching from a biologically active waste, and
so no special precautions are required in the tests to insure inhibition
of bacterial action with wastes that are at least no more active biolog-
ically than shredded refuse.
105
-------
SERIES B2, CUMULATIVE RELEASE AFTER 3 DAYS
Eg/Kg
50O-
400- •
300--
2OO--
100- -
Zn »1
K * | DUPLICATES
MgwJ
50 -r
4O
30"
20--
10--
COD « DUPLICATES
•4 I-
DIST. COPPER THYMOL SILVER
H20 SULFATE
NITRATE
DIST.
H20
COPPER THYMOL SILVER
SULFATE NITRATE
DIST. COPPER THYMOL SILVER
H20 SULFATE NITRATE
Figure 47. Cumulative releases of several parameters for municipal refuse leached with distilled
water containing bacterial inhibiting agents, series B2.
-------
MAXIMUM CONCENTRATIONS AFTER 3 OR 7 DAYS
SERIES B3, 7 DAYS
20--
DIST.
H20
ppm
40OO-T
3000--
2000--
COPPER THYMOL SILVER
SULFATE NITRATE
1000
COO
DIST
HgO
ppm
25O-1-
20O--
150
COPPER THYMOL SILVER
SULFATE NITRATE
Na •
-f-
DIST. COPPER THYMOL.SILVER
H2O SULFATE NITRATE
SERIES 84, 3 DAYS
30--
DIST.
ppm
80O-r
600--
400--
COPPER THYMOL SILVER
SULFATE NITRATE
200
DIST.
H2O
ppm
I2SOO-T
IOOOO--
7SOO
COPPER THYMOL SILVER
SULFATE NITRATE
DIST COPPER THYMOL SILVER
H20 SULFATE NITRATE
Figure 48. Maximum concentrations of several parameters for municipal
refuse leached with distilled water containing bacterial
inhibiting agents, series B3 and 84.
107
-------
SECTION 7
SUGGESTED PROCEDURE FOR A STANDARD LEACHING TEST
This chapter will provide an overview of the suggested leaching
test procedure. Figure 49 shows a flow scheme emphasizing the sample
preparation steps of the suggested standard leaching test. In general,
initial sampling of a waste will be done by non-laboratory personnel.
Obviously, major errors can arise from improper sampling, but this
aspect of the test was not included in the present study. It must be
assumed that the sample is representative of the waste that is to be
tested and possibly landfilled.
Unless the waste is homogeneous3 subsampling must be done care-
fully, and innovative techniques will often be necessary. Several dif-
ferent techniques may be required. Some techniques have proven useful with-
in this study. Sand-splitters are good for dividing solid, granular
wastes. They consist of parallel troughs which alternate in depositing
the material poured onto the splitter to the left or right. Manual mix-
ing of a bucket of fly ash or foundry sand wastes, for example, was not
adequate for the purposes of this study.
Liquid wastes can normally be mixed sufficiently to allow repre-
sentative subsampling. In some cases, what appears to be a mixable
liquid waste may have a sludge or immiscible layer at the bottom. It
is always necessary to check for this with a stick, glass tube sampler,
etc. In such cases it may be necessary to sample each layer separately,
mixing them in the proper proportions for the leaching test.
Suspensions or solid-liquid mixtures can be very difficult to work
with. If mixing does not provide uniformity, it may be necessary to
sample solid and liquid portions separately, combining them for the
leaching test, or even to keep them separate and run the test for each
component, and mathematically synthesizing the results according to the
original amounts of each material in the sample. This technique may
also be necessary with some wastes containing solid components of dif-
ferent composition or leaning characteristics. It may be necessary to
determine the amount of each distinct component present in the original
waste, run the test for each component, and mathematically combine the
results. The problem with running the leaching test separately for
different components of a waste is that any interactions between compo-
nents affecting the leaching patterns can unnaturally affect the results.
This is not felt to be a problem with wastes arising from a single source,
but could be important if different wastes are combined in the sample
sent to the laboratory.
The test utilizes only the solid portion of the waste being studied.
The liquid portion, namely that which will pass through a 0.45 micron
filter, is analyzed directly for the components of interest. The rationale
for the separation is that the liquid component of the waste can move away
from the solid portion in the landfill, either due to gravity or capillary
flow, or to absorption by surrounding materials. The liquid component of
a waste represents an intrinsic potential impact on water quality as a
result of waste disposal which is not dependent on external sources of
water or leachinq media. The solid portion remains behind for leaching,
as simulated by the leaching test.
108
-------
INITIAL SAMPLING IN INDUSTRIAL
PLANT; TRANSPORT TO TESTING
LABORATORY
REPRESENTATIVE SUBSAMPLES TAKEN
OF WASTE OR WASTE COMPONENTS
SOLID-LIQUID SEPARATION
LIQUID
SOLID
PREPARATION FOR SLT;
FURTHER SUBSAMPLING
SELECTION OF
LEACHING MEDIA!
STANDARD LEACHING
TEST
SOLID-LIQUID SEPARATION
LIQUID
SOLID
PRESERVATION
IAN A LYSIS I
Figure 49. Waste handling process.
109
-------
In performing the solid-liquid separation, it is necessary to filter
either the whole amount of waste in the sample, or to take a representa-
tive subsample, and perform the solid-liquid separation sten using a
0.45 micron filter. Figure 9 (page 30, solid-liquid separation section)
summarizes the recommended separation scheme which was found to be
successful for all of the wastes tested. Note that centrifugation
can be used if the filtration speed is too slow, and that the use of a
pressure filter is also recommended if it is necessary to speed filtra-
tion. The final step is always the filtration of the liquid through a
0.45 micron filter. If it is not possible to perform a solid-liquid
separation after using the steps mentioned in Figure 99 the residue on
the filter is declared to be a solid for the purposes of subsequent
testing. If the separated liquid portion of the waste is found to be
hazardous, the test is terminated; otherwise the solids must be homog-
enized so they are representative and can be used in the leaching test.
Bulky materials have to be reduced to smaller particles, e.g., 1 cm
particle size.
The Leaching Test Procedure
The solids obtained from the sampling and solid-liquid separation
processes are next leached in the following recommended procedure. First,
the solid content of the solids has to be determined. This is because the
leaching procedure calls for a set ratio of solids to leaching media
based on dry weight solids. This is no problem with materials that are
basically dry, such as fly ash, or with viscous sludges, etc., in which
case the water content may be assumed negligible and the solids weight
considered the dry weight. If the solids are highly absorptive, or if
they contain volatile organics, problems develop. In the case of
volatile organics, the dry weight, determined by drying to constant
weight at 105°C, is continually changing depending on several factors
including the volatility of the various components. Because the solid-
liquid ratio is not as critical for testing purposes as it is for con-
sistency and interpretation of the results, it is suggested that whatever
weight is obtained after 24 hours drying at 105°C in a forced air convec-
tion oven be considered the dry weight for the purposes of the leaching
test. Note that this "dry" weight, whatever it may be, can always be
related back to the original waste sample as received, as a fraction or
percentage of that sample, for purposes of interpretation.
Absorptive wastes present another problem. Wastes such as paper
mill sludge or municipal refuse have a high absorptive capacity, so that,
if such wastes are dried and mixed with the leaching media in the required
proportions, they will soak up a major fraction of the leaching media,
leaving little media available for analysis after solid-liquid contact.
Further, subsequent elutions will have in effect a high solid-liquid
ratio if the liquid is replaced by only as much leachate as was able to
be separated in the case of procedure R, thereby slowing the release
process. In procedure C, large amounts of waste and liquid must be
handled to provide sufficient leachate for analysis, and replacing the
waste in effect ties up or removes amounts of leaching media necessary
to wet it. In effect, the solid-liquid ratios are not what was originally
specified for test consistency with different wastes, and operational prob-
lems due to leaching media loss result.
110
-------
It is recommended that absorptive wastes be dried to determine the
dry weight, then an amount of wet waste necessary to meet the 1:10 solid-
liquid ratio requirement (dry weight) be used in the various elutions.
Note that the test results can still be related to the dry weight of the
waste as received. Note also that the final composition of the liquid
added to the leaching media in the form of liquid content of the waste
(of known composition because it is analyzed earlier as immediately
available) can be assumed equal to that removed at the end of each elu-
tion for analysis. Thus, this amount may be included in the total
release obtained in the test. If the waste is very wet, so the liquid
portion dilutes the leaching media to a significant degree, a more con-
centrated leaching media stock solution can be used, such that dilution
by the liquid in the waste results in the normal concentrations. A cor-
rection curve to account for dilution o'f leaching media other than dis-
tilled water is included in the Appendix as Figure A-l.
Two elution procedures are used in the test, as shown in Figure 50;
one in which the waste is replaced in each solution (Procedure C) and
one in which the leaching media or eluent is replaced (Procedure R).
Procedure C is designed to estimate the maximum concentrations of leach-
able species arising in the leachate as a result of leaching media con-
tact with the solid portion of a waste, while Procedure R estimates the
amounts of leachable species to be released. The latter may be expressed
with most wastes on a weight of each constituent released per unit weight
of waste basis, for example. The results of Procedure C are especially
influenced by the waste, while Procedure R is more influenced by the
leaching media. Both procedures use three 24-hour elutions with appro-
priate leaching media.
The choice of the leaching media used in the standard leaching test
depends on the purposes of the test. Distilled water is to be used in
all cases. It provides a data base for comparing different wastes, test
procedures, and leaching media. Distilled water simulates rainwater
and, so, it simulates the leaching capability of the waste when landfilled
by itself or in situations where it controls leaching media composition.
It also simulates contact with very old landfill leachate. As long as an
industrial waste is landfilled in the open air, it will always be con-
tacted for a certain time period with rainwater. Table 21 snows the
relationship between the choice of the leaching media and the kind of
landfill of interest for a specific waste.
The choice of the leading media is very important for it has a
substantial effect on the results. The interpretation of the standard
leaching test has to be done very carefully, taking into account the
leaching media. The synthetic landfill leachate should be used if a
certain waste is to be landfilled together with municipal waste. Direc-
tions for its preparation were presented in Table 14. It may be difficult
to decide what leaching media should be used when the waste is to be
landfilled with other kinds of industrial wastes which may control the
leaching media composition, whether in an industrial or municipal landfill.
Acid, base, or other leachates should be used, depending on the specific
situation, or a leaching media obtained by prior contact of the other
waste(s) and distilled water can ae used. If the other wastes are biologi-
cal ly decomposable, a leaching media similar to the synthetic landfill
leachate may be most appropraite.
m
-------
THE STANDARD LEACHING TEST FLOW SCHEME |
JDETERMINE~MQISTURE CONTENT]
Procedure C
EQUILIBRIUM CONCENTRATION
TEST
[SOUP-LIQUID RATIO MO
SEPARATE,
SOLIDS REMOVED
PORTION OF LIQUID
REMOVED FOR ANALYSIS
REPLACE SOLIDS
SOLID-LIQUID RATIO l'7.3
SEPARATE,
SOLIDS REMOVED
PORTION OF LIQUID
REMOVED FOR ANALYSIS
REPLACE SOLIDS
SOLID-LIQUID RATIO I'5.0
SEPARATE
LIQUID REMOVED
|DAY2]
DAY 3
Procedure R
MAXIMUM RELEASE TEST
SOLID-LIQUID RATIO I'10
SEPARATE,
LIQUID REMOVED
REPLACE LIQUID
SOLID-LIQUID RATIO MO
SEPARATE,
LIQUID REMOVED
REPLACE LIQUID
SOLID-LIQUID RATIO MO
SEPARATE
LIQUID REMOVED
FURTHER LEACHING OF SOLIDS
IF NECESSARY
ANALYZE AND INTERPRET
RESULTS
Figure 50. The recommended standard leaching test flow scheme.
112
-------
TABLE 21. LEACHING MEDIA SELECTION ACCORDING TO LANDFILL CONDITIONS
Leaching Media Landfill
Distilled water to be used always, mono landfill
Synthetic leachate industrial waste + municipal waste
0.1N H2S04\ municipal or industrial landfill;
0.1N NaOH } dependent on specific conditions
Others (organic solvents, liquids contacting the waste with other
with high complexing capacity, etc.) liquids in landfills containing
other industrial wastes
In some cases the leaching test may be used to assess the effect on
leaching of landfill ing the waste being tested by itself or with other
wastes. For example, one result might be that a particular waste should
not be co-landfilled with acid wastes because the elution rate is extremely
high.
For the first elution, both Procedures C (maximum concentration) and
R (maximum release) use a 1:10 solid to liquid ratio (dry weight to volume).
A separate sample of the waste is used to determine dry weight. In Pro-
cedure C, at the end of the first elution the sample is filtered, the
solids discarded, and a portion of the leachate taken for analysis. An
amount of fresh waste equal to that originally used (prewetted if neces-
sary) is then added to the leachate. The amount of waste added is such
that the solid to liquid ratio is 1:7.5 and 1:5 in the second and third
elutions, respectively. The test is ended after the third elution.
Procedure R uses fresh leachate on the same waste sample for each elution,
thus maintaining a constant solid/liquid ratio of 1:10. More than three
elutions may be used if there is reason for the additional elutions
(such as variable leachate composition after each successive elution).
The test is run at ambient temperatures, unless special laboratory
or landfill conditions dictate the use of another constant temperature,
which should then be specially noted in the test records and reports.
The test flasks should not be exposed to abnormal laboratory temperatures
(sun, furnace, open windows, etc.).
A rotating mixer is used in conjunction with a square sample bottle.
The mixer is tilted to give an almost-vertical rotational plane. As the
bottles turn, the samples slide down the square sides and turn over some-
what in the process rather than simply staying at the bottom as would be
the case in a round bottle. This agitation technique has been found to
give good mixing with little or no abrasion. A rotation speed of 1 to 2
rpm is used. Square polyethylene containers are normally used, but glass
flasks should be used when the plastic may affect the results. In gen-
eral, plastic flasks are better if inorganic constituents in the leachate
are of major concern, and glass flasks for organic constituents.
113
-------
The amount of leaehate and waste used Is dependent on how much
sample volume is needed for analysis, and in some cases on the minimum
reasonable waste sample size. If only atomic absorption is to be used,
for metal -analysis, a sample volume of 100 ml is normally sufficient.
That means for Procedure C at least 30 g of waste (dry weight basis) and
300 mis of leachate should be used. In Procedure R at least 10 g of
waste (dry weight) and 100 mis of liquid would have to be used. It is
recommended to use at least twice the above amounts, however, for some
leachate is lost in the process of multiple elutions, or remains in the
waste, filter, centrifuge tubes, glassware, etc. It is also recommended
to choose the size of the square flasks according to the amount of leach-
ate and waste required in order to fill up the flasks completely so that
only a very small amount of air is in the flasks. This is especially
important when the synthetic leachate:is used so there is not enough
oxygen trapped in the flasks to change the leachate composition signifi-
cantly. If more than a few mis air space exists in a flask, it should
he purged with, nitrogen.
The test should be run with sufficient replicates to determine
statistical reliability. Using sampling techniques described earlier,
all of the wastes tested in this project gave reasonable reproducibility,
and duplicates were sufficient. With very nonhomogeneous wastes, or
wastes generally difficult to sample, a large sample size and more
replicates will be required.
If gas production occurs in the flasks, the pressure should be
released by using a pressure release valve (a spring-held ball valve
worked satisfactorily), or by unscrewing the cap periodically until
the gas is vented. After each elution, the solids and liquids are
separated according to the same solid-liquid separation scheme used
initially with the waste. Normally, 0.45 micron filtration occurs
readily because of prior sample treatment and filtration. Filtration
is necessary to obtain leachate for analysis and to replace either the
solid or liquid fractions.
Leachate analyses are performed according to standard procedures.
The selection of elements or compounds to be analyzed is waste dependent;
however, in addition to specific species of interest because of the
nature of each waste, or of interest for regulatory purposes, it is
suggested to measure parameters that help in interpreting the results,
such as pH, redox potential, specific conductance, COD, etc. If the
leaching media used is synthetic leachate, some parameters cannot be
measured accurately unless very high concentrations are leached,
because these parameters are ingredients of the synthetic leachate.
This includes Na, $04, Fe, and COD, plus the specific organics pyrogallol,
acetate, and glycine.
During the test, observations should be written down such as change
of the waste (color, particle size, appearance, odor, etc.), leachate
(color, odor, etc.), gas production in the flasks, precipitation, etc.
Such observations may be helpful in interpreting the results.
114
-------
Presentation of the Results from the Standard Leaching Test
In this section some suggestions are made for summarizing and
presenting the cumulative release and concentration data from the leach-
ing test. Of course, the standard leaching test results from each waste
have to be interpreted individually, but a standardized procedure for
presenting the results may help to compare the leaching characteristics
of different wastes and with different leaching media.
The results of the standard leaching test should be presented in
the form of concentration and cumulative release curves for both Pro-
cedures C and R as shown in Figure 51. The cumulative release in mg/kg
waste is based on the dry weight of the waste as used and defined in
the standard leaching test procedures. Calculation of the cumulative
release is performed by adding the product of the concentration of each
chemical species and the volume of leachate obtained for each elutria-
tion as shown in Table 22. For many wastes the curves will be similar
to those presented in Figure 51. With Procedure C, the concentration
increases with the number of elutions, for the waste is replaced after
each elution and the liquid stays in the flasks. Thus, the leaching
media is repeatedly contacted with fresh waste. The cumulative release
curve for Procedure C may increase, stay constant, or decrease, depend-
ing on the slope of the concentration curve. The reason for these pos-
sibilities is that after each elution the waste is replaced by new non-
leached waste. Therefore, the cumulative release after the second
elution, for example, has to be related to the amount of waste used in
both the first and second elutions.
With Procedure R, where the waste stays in the flasks for the
whole test period and the liquid is replaced after each elution, the
concentration will normally decrease with the number of elutions. As
long as the concentrations of the second and subsequent elutions are
not zero, the cumulative curve will increase.
There are situations in which the curves look quite different from
those presented in Figure 51. This may happen, for example, with those
parameters of solubility characteristics dependent on pH and with wastes
which cause a pH change during the leaching test. In some cases the
same concentration of some parameter is always reached in subsequent
elutions using Procedure R. This means that the material is very soluble
and there is a continuing supply of available material sufficient to
approach solubility limits. The percentage of release of this specific
parameter is constant with each elution. In this case, for a rough
estimation of how many elutions may be necessary before the concentration
drops, knowledge of the total amount of this parameter in the waste is
useful:
The range in relative release rates is illustrated in Table 23 which
presents the percentage release of four metals from papermill sludge (N),
after three elutions. The composition of the papermill sludge was pro-
vided by the manufacturer and can only be assumed to be correct for the
sample tested. It is interesting that the percentage release of the
different elements is so different. The results suggest that Ca and Fe
may leach from the papermill sludge for a long time, where K is very
soluble and leaches at relatively higher rates for a shorter period. Mg
may be in between. Explained differently, it can be expected that the K
concentrations will decrease after a relatively short time while Ca and
Fe will leach at approximately the same rate for a long time.
-------
Procedure C, Concentration X(ppm) Procedure C, Cumulative Release X(mg/kg)
cone.
release
1 2 3 [elutions (days)] 1 2 3 [elutions (days)]
Procedure R, Concentration X(ppm) Procedure R, Cumulative Release X(mg/kg)
X
X
I 1
1 23 [elutions (days)] 1 2 3 [elutions (days)]
Figure 51. Suggested presentation of leaching test results
for species X from a waste.
116
-------
TABLE 22. CALCULATION OF CUMULATIVE RELEASE FOR
PROCEDURES C AND R
Definitions:
C. = concentration of leachate after ith_ elution, mg/i.
I. = volume of leachate withdrawn after 1th elution,£.
w = weight of dry waste used in each elution, kg.
R. = release from 1th elution, mg/kg.
i ~"~"
R = cumulative release, mg/kg.
Procedure C: (replacement of waste)
Elution 1: -~- « R]
(C. - C,H? C,A, + (C2 -
Elution 2: = R R = ~U -
(C - C ) , C,A, + (C - C,)A2 + (C - Cj£
Elution 3: 3 2 A3 - R R = -^ - ^ - - * - ^-
Procedure R: (replacement of leaching media)
C,£,
Elution 1 :
Elution 2:
Elution 3:
where
w Kl U2
f*n 4. p n J, C 9
Vl L2*2 L3*3 _ R .
R w Kl
R "f*
117
-------
TABLE 23, PERCENTAGE RELEASE RESULTS FOR PAPERMILL SLUDGE
Element
Ca
Fe
K
Mg
Original Concentration
in Sludge
[mg/kg]
12,000
2,800
200
7S400
Elution*
[mg/kg]
38
3.7
73
340
% of Original Amount
in Sludge Released
0.32
0.13
36.5
4.6
*
After three days, based on dry weight, Procedure R.
It is often very time consuming and difficult, and in some cases
impossible, to make a total digestion of a waste for the quantitative
determination of its composition and to estimate total ultimate release.
Accordingly, such a determination cannot be suggested as part of a
standard leaching test, but it is recommended to obtain such information
whenever it is critical or when it is not difficult to get the overall
composition of the waste. It may be very helpful in interpreting the
results.
A. Example of Presentation and Discussion of Results
from a Standard Leaching Test
An example of the presentation of results from the leaching test
procedure is shown in Figures 52 through 54 in which the copper oxide-
sodium sulfate slurry waste was tested. For this particular test, a
solid-liquid ratio of 1:7.5 (wet weight waste) happened to be used instead
of 1:10 (based on dry weight). This does not affect the general pattern
of the results. Distilled water and synthetic leachate were used as
leaching.media for 5 elutions. The maximum release (replacing the liquid)
test Procedure R was done in duplicate. Figure 52 shows the influence of
the test procedure and liquid on the pH values. Distilled water after
contact with the waste had a pH in the 10 to 10.5 range. The pH values
of the maximum concentration Procedure C are slightly higher, as would
be expected. Especially when synthetic leachate was used, the conceptual
differences between the two test procedures are obvious from the pH results,
Procedure R pH was influenced by the leaching media pH and maintained
acidic levels as the synthetic leachate buffered or controlled it at or
near pH 4.5. With Procedure C, the buffering capacity of the synthetic
leachate was overcome after the first elution and the pH was determined
by the waste more so than by the leaching media. Note that the opera-
tional aspects of redox control were not perfected with the synthetic
leachate at the time these results were obtained.
118
-------
COPPER OXIDE- SODIUM SULFATE SLUDGE
A SYNTHETIC LEACHATE • H^O
pH
U.OT
IO.O+
9.0-•
8.0 - •
7.0-•
6.0 ••
5.0--
4.0
^.
2345
ELUTIONS
'PROCEDURE C
•PROCEDURE R
REDOX, mV
EOO-r
I50--
IOO--
50--
0--
+ 50
4—i
\\
\;
2345
ELUTIONS
Figure 52. pH and redox from copper oxide-sodium sulfate'sludge.
119
-------
COPPER OXIDE- SODIUM SULFATE SLUDGE
K CONCENTRATION 8 RELEASE
A SYNTHETIC LEACH ATE «H 0
PROCEDURE C
CONCENTRATION, ppm
40-^
RELEASE, 2mg/kg
150-r
125
100
75
PROCEDURE R
CONCENTRATION, ppm
RELEASE, Img/kg
5-r A 250i-
200
150
100- •
50
2345
ELUT10NS
2345
ELUTIONS
Figure 53.
K concentration and release from copper oxide-sodium
sulfate sludge.
120
-------
COPPER OXIDE - SODIUM SULFATE SLUDGE
Cu CONCENTRATION & RELEASE
A SYNTHETIC LEACHATE • H?0
PROCEDURE C
CONCENTRATION, ppm
3,000T
2,000--
1,000-•
RELEASE, ZgAg
60T
40-•
20 ••
PROCEDURE R
CONCENTRATION, ppm
5,OOOT
RELEASE, 2g/kg
125 T
100-•
234
ELUT10NS
2345
ELUT10NS
Figure 54.
Cu concentration and release from copper oxide-sodium
sulfate sludge.
121
-------
The potassium concentration and release curves in Figure 53 are
typical for chemical parameters for which release is not pH dependent.
Procedure C shows increasing concentration levels as the number of
elutions increases. The total release after 5 elutions using synthetic
leaching media was approximately equal to that obtained using distilled
water.
Compared with Procedure C, the results from Procedure R are very
different. The concentration of potassium decreases with succeeding
elutions in Procedure R, while the cumulative release increases. For
this parameter, Procedure C shows highest concentrations with the
tendency of further increases with more elutions. Procedure R indicates
that the potassium dissolves quickly, and that the largest concentrations
might be expected in the first phase.qf landfilling. The replacement of
leachate in successive elutions in Procedure R resulted in more Teaching-
media dependency. The release with synthetic leachate was approximately
double that using distilled water. After the large release from the
first elution, the additional release (and concentrations) in subsequent
elutions was basically constant, with synthetic leachate much more
aggressive in leaching K than distilled water. This is probably due to
the more rapid dissolution of the wastes by the synthetic leachate, bring-
ing about an attendant release of K.
The results from both test procedures are different when the solu-
bility of the measured parameters is pH dependent. An example of this
situation is presented in Figure 54, where copper values are plotted.
The use of distilled water as a leaching media resulted in no copper
elution, whereas the concentrations resulting from use of synthetic
leachate were extremely high. The use of distilled water only would
have led in this case to unrealistic predictions of the leaching
characteristics of this copper oxide-sodium sulfate slurry when co-
landfilled with municipal refuse. The copper is very soluble in syn-
thetic leachate, probably because of the acidic pH levels.
Of special interest is the decrease of copper concentration with
the number of elutions,, This occurred with both procedures, even though
Procedure C is supposed to result in increasing concentrations to the
maximum levels obtainable. In this case the basic nature of the waste
nearly exhausted the buffering capacity of the synthetic leachate after
the first elution and completely controlled the pH by the fourth elution.
The solubility of copper, therefore, decreases with subsequent elutions
as the pH rises. pH was not the only elution factor affecting Cu release,
however, as shown by the results of Procedure C using synthetic leachate.
Even though pH values of 9.3 and 9.9 were attained in the third and
fourth elutions, at which levels the copper concentrations should have
been negligible according to the results using distilled water as the
leaching media, the complexing capacity of the synthetic leachate
evidently resulted in the high Cu concentrations observed of 800 and
550 ppm.,
122
-------
If it is assumed that Cu, Mg, and Na are the only major cations of
the copper oxide-sodium sulfate slurry waste, and exist in the compounds
CuO, MgS04, and Na2S04, basically 100% of these materials were leached
in the five elutions in Procedure R using synthetic leachate as a leach-
ing media. Na values used for this calculation were those measured in
distilled water because of the high background level of Na in the syn-
thetic leachate. The calculated percentages are 99.43 and 107.5% for
the two duplicate runs.
The results of the leaching test in which the copper oxide-sodium
sulfate slurry was used are not typical of all wastes, because this waste
is very soluble under the described conditions. This example was chosen
because it shows very clearly the effect .of the synthetic leachate and
the two test Procedures C and R on the waste's leaching characteristics.
The interpretation of the test results illustrates the benefit of using
both procedures and leaching media in the leaching test.
Absolute meaningful interpretation of the results from the leaching
test to describe the potential environmental hazard of the waste is very
difficult to do. One observation that is clear is that the described
results of the copper oxide-sodium sulfate slurry indicate that this
waste should not be landfilled together with municipal waste unless
special precautions are taken, because the release of copper is very
high in this situation.
Interpretation of Leaching Test Results
It is clear that no finite laboratory leaching test can predict with
certainty the long term leaching pattern of a waste in a landfill. A
compromise must be made in selecting either a batch (flask) test or a
column test, and, once that basic decision is made, a multitude of con-
ceptual and operational decisions must be made in specifying exact test
procedures. The alternative of leaving such decisions for the laboratory
technician to make for each waste, as seems appropriate, eliminates stand-
ardization of procedures and direct comparison of the results from one
laboratory to another, from one waste to another, etc. Additional com-
promises have been made and operational variables and techniques have
been evaluated and specified as recommended as part of this study, but
the test results are, at best, difficult to apply to full-scale landfill
situations.
Numerous test conditions were studied as part of this research. Such
variables as choice of leaching media, solid-liquid ratio, number of elu-
tions, time per elution, agitation technique, temperature, surface area
of contact, biological effects, sampling and sample preparation, solid-
liquid separation, and others were considered. Of the leaching test
conditions, leachate composition and temperature are most readily related
to landfill conditions. Other test conditions are more difficult to base
on landfill conditions and were chosen based on criteria other than land-
fill modeling. Since these conditions can affect a parameter's concentra-
tion in the test leachate, caution must be exercised in data interpreta-
tion. One cannot always transpose test data to landfill practice directly.
123
-------
It may be possible to correlate test conditions with landfill concen-
trations by running extensive verification tests, correlating a waste's
behavior in the test with the behavior of the same waste in a carefully
monitored landfill. Correlation coefficients could then be developed
for parameters and conditions similar to those in the verification studys
and the test result used to estimate landfill concentrations.
A short leaching test cannot duplicate completely the long-term
leaching characteristics of a waste. The short test might miss com-
pletely a parameter having exponential release or might overestimate
the release of a parameter showing a concentration maxima. These pat-
terns could be seen in a long-term study, but are difficult to determine
in a short test.
When interpreting test results, it is important to consider the
physical condition of the landfilled waste. Of special concern in this
regard would be a waste which is landfilled in large stable chunks or
with a stable impervious coating which could behave far differently in
a landfill than in a test in which it were ground. Although not specifi-
cally tested as part of this study, it seems reasonable to cut, crush
or specially make such wastes to yield particles approximating the size
equivalent to a one cm cube, for example. This particle size is small
enough to work in the procedure, yet large enough to not increase
drastically the surface area per unit waste exposed to leaching. Inter-
pretation of results may involve use of a factor compensating for the
increased surface area obtained because of size reduction techniques.
A simple ratio between the most likely surface area of the waste in
the landfill per unit weight to the surface area per unit weight for the
particle size as tested could be used to adjust at least the initial
results for cumulative release. If subsequent elutions indicate negli-
gible particle breakdown or secondary release with time, such a technique
should be adequate.
An evaluation of the hazardous nature of a waste must incorporate
an evaluation of the waste's landfill environment. The hazardous nature
of a waste is a sfutation-specific characteristic. For example, a waste
may be hazardous to an organism under one set of environmental conditions,
yet completely innocuous under a different set of conditions. Further-
more, its hazard may be organism specific; i.e., it may be hazardous to
one organism and not to another under the same set of conditions. Thus,
a determination of the hazardous nature of a waste must include an evalu-
ation of its effect on specific organisms (or plants or animals, etc.)
under specific conditions.
Some appreciation for the release and concentration levels obtained
may be obtained by comparing results from the leaching test of the waste
in question with various natural materials. For example, the leaching
test was run on park soil, municipal waste (City of Madison) and dried
digested sewage sludge (from the Madison Metropolitan Sewage District
Nine Springs Sewage Treatment Plant) in order to generate background
data on leaching of more or less natural materials. These results are
shown in Tables 24 and 25. It is clear that some materials which are
124
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TABLE 24, MAXIMUM CONCENTRATIONS AFTER THREE ELUTIONS OF SOIL, MUNICIPAL REFUSE
AND SEWAGE SLUDGE IN mg/fc, PROCEDURE C
Substance
Soil
Municipal
^Refuse
>
i
Dried
Digested
Sewage
Sludge
Leaching
Media
Dist. H00
C.
0.1 N H2S04
Dist. H20
Syn. leach.
0.1 N H2S04
Dist. H90
i.
Syn. leach.
0.1 N H2S04
Cu
0.03
0.11(0.44)
3.24
2.75(4.0)
3.83(5.3)
0.09
0.9(1.02)
0.39(3.1)
Zn
0.02(0.04)
2.43(3.87)
21.1
47
25.9
0.58
26.5(29)
36
Fe
0.15(2.6)
3.4(99.6)
22,5
72.9
4.95
1.2(105)
Mg
17
372(429)
109
131
247
146
190
210(296)
Pb
b.d.l.
1.1(1.7)
1.4
6.9
1.4(2.66)
b.d.l.
b.d.l.
(2.65)
Na
162
838
1680
1430
203
_ _ __
219
K
16.2
46.2
306
306
226
69.3
64.8
71.1
b.d.l = below detection limits.
Note; Number in parentheses signifies maximum concentration measured if not attained after
three elutions.
-------
ro
TABLE 25. CUMULATIVE RELEASE AFTER THREE ELUT10NS OF SOIL, MUNICIPAL REFUSE,
AND SEWAGE SLUDGE IN mg/kg DRY WASTE. PROCEDURE R
Substance
Soil
Municipal
Waste
Dried
Digested
Sewage
Sludge
Leaching Media
Dist. H20
Syn. leach.
0.1 N H2S04
Dist. JU)
c
Syn. leach.
0.1 N H2S04
Dist. H00
c.
Syn. leach.
0.1 N H2S04
Cu
0.3
2.3
6.4
12.8
122
630
0.7
20.5
39.7
Zn
0.7
54.2
67.5
73.6
338
470
2.1
606
811
Fe
27.8
1140
94.2
1990
7.3
1110
Mg
109.8
2720
8900
479
560
4190
347
1590
6180
Pb
b.d.l.
22.5
33.8
b.d.l.
105
67.1
b.d.l.
b.d.l.
26.5
Na
3430
3300
5060
5250
1787
____
2310
K
144
515
440
1510
7580
1710
194
604
456
b.d.l. = below detection limits.
-------
regularly deposited on soil, or exist in soil, can be released via a
leaching process in amounts comparable to some industrial wastes. It
may also be that the natural soils at a particular location have a *
beneficial effect in attenuating or otherwise changing contaminant
release rrom a waste. Perhaps a test procedure would be useful in
which samples of the soils of interest at a specific site are added
in varying amounts to the leaching test flask to better predict any
relationships that might occur between soil and the waste in a landfill.
One obvious way to interpret the leachate composition results is
to compare the concentrations of the various chemical species to some
standard, for example drinking water standards. This is dangerous,
however, and is difficult to defend for the leaching test developed in
this study. Obviously, test requirements could have been adjusted to
yield virtually any concentration of Teachable species in the leachate
for analysis. This could have been done, for example, by use of dif-
ferent elution times (e.g., 5 minutes instead of 24 hours), or solid-
liquid ratios. The test was designed to be rapid, aggressive, and to
yield as much information about the leaching characteristics of a waste
as possible in a relatively short time. It was not designed to provide
realistic concentrations of the various species for a specific situation.
One method for interpretation of test results involves adjustment
of measured chemical species concentrations by a factor. This factor
may be based in part on the amount of leaching media the waste might
contact during the estimated active life of the landfill. Thus, the
cumulative infiltration expected over a ten-ye*ar period at an appropri-
ate landfill might be used. For example, if a waste is found to release
a total of 0.1 gram of a chemical species of concern S per kilogram of
waste in the leaching test, and the waste is to be landfilled in an area
that receives an average of 100 cm precipitation per year of which 25% is
net infiltration and results in leaching, the 'following calculation can
be made. The average concentration of S over an assumed active leaching
life of 10 years from one ton of waste is C.
1000 kg waste x °-1 9 *Pes S = 0.1 kg species S evolved
2
Assume the waste is landfilled so that 1 meter landfill area holds 1 ton waste.
£-= _ _ 0.1 kg S x 1Q6 mg/kg _
10 years xi.O 5LEEiIL.x0.25(fract.1nfiH.)xl m2(surface area) x 1000 1/m3
The selection of numbers may be unrealistic (for example, tne use of one
meter thick landfill), but the example illustrates an attempt to relate
average release data to landfill conditions. The above calculation could
be further modified by the amount of waste expected to be landfilled per
unit landfill area.
127
-------
Another way of developing interpretive criteria when toxic effects
are of primary concern would be to dilute both the leaching media and
the elutriates obtained by waste contact to the point where no toxic
effects are noted in a toxicity test. The difference in dilutions
required to provide no toxic effects could be a measure of the incre-
mental effect of the Teachable constituents of a waste on the leaching
media, and would, thus, be an indication of the hazardous character of
the waste. The difference would have to be interpreting knowing that
the test is designed to be aggressives but at least the various base-
level degrees of toxicity inherent in the selection of the raw leach-
ing media are taken into account.
In summary, the standard test provides a rapid indication of which
chemical species are immediately leached from a waste, and an indication
of the maximum concentrations of each specie likely to be found in the
leachate. In addition, an estimate of the amount of each specie likely
to be released per unit weight of waste is obtained. Finally, the test
can provide valuable information with regard to the relative effect of
co-disposal of the waste in question with other wastes or mixed municipal
refuse. The fact that the test is not perfect in predicting the long-
term leaching pattern of a waste, or the precise concentration of a
particular parameter in a particular landfill, for example, means that
the test results need to be interpreted with care.
128
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REFERENCES
1. Abelson, A. and Lowenbach, W., "Procedure Mannual for Environmental
Assessment of Fluidized Bed Combustion Processes," Mitre Corp.,
M77-34, January 1977.
2. Lee, G.F. and Plumb, R.H., "Literature Review on Research Study
for the Development of Dredged Material Disposal Criteria,"
Contract Report D-74-1, Office of Dredged Material Research,
U.S. Army Engineers Waterways Experiments Station, Vicksburg,
Miss., 1974.
3. Boyle, W.C., Ham, R.K., Kunes, T., liu, T., and Kmet, P., "Assess-
ment of Leaching Potential from Foundry Process Solid Wastes,"
Final Report, submitted to American Foundrymen's Society, Des
Plaines, Illinois, August 1977.
4. American Public Health Association, Standard Methods for the
Examination of Water and Wastewater. 13th Edition, APHA, Inc.,
New York, (1971).
5. Emcon Associates, "Twelve Month Extension—Sonoma County Solid
Waste Stabilization Study," Department of Public Works, Sonoma
County, California, (1976).
6. Emcon Associates, "Sonoma County Refuse Stabilization Study.
Third Annual Report," Department of Public Works, Sonoma County,
California, (1974).
7. Pohland, F.G., "Sanitary Landfill Stabilization with Leachate
Recycle and Residual Treatment," EPA Report 6000/2-75-043, EPA,
Cincinnati, Ohio, (1975).
8. Fungaroli, A.A., "Polution of Subsurface Water by Sanitary Land-
fills," EPA Report SW-12RG, EPA, Washington, D.C., (1971).
9. Qasim, S.R. and Burchinal, J.C., "Leachate from Simulated Land-
fills," Jour. Water Poll. Control Fed., 42_(3), 371, (1970).
10. Chian, E.S.K. and DeWalle, F.B., "Evaluation of Leachate Treat-
ment, Volume 1: Characterization of Leachate," EPA Report
600/2-77-186a, EPA, Cincinnati, Ohio, (1977).
11. Steiner, R.L., Fungaroli, A.A., Schoenberger, R.J., and Purdom, P.W.,-
"Criteria for Sanitary Landfill Development," Public Works, 102(3),
77, (1971).
12. Clark, T.P. and Piskin, P., "Chemical Quality and Indicator Param-
eters for Monitoring Landfill Leachate in Illinois," Environ. Geo.
1, 329, (1977).
129
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13. Hughes, G.M., Landon, R.A., and Farvolden, R.N., "Hydrogeology
of Solid Waste Disposal Sites in Northeastern Illinois," EPA
Report SW-12d, EPA, Washington, D.C., (1971).
14. Burrows, W.D. and Rowe, R.S., "Ether Soluble Constituents of
Landfill Leachate," Jour. Water Poll. Control Fid.s 47(5), 921,
(1975).
15. Robertson, J.M., Toussaint, C.R.S and Jorque, M.A., "Organic Com-
pounds Entering Ground Water from a Landfill," EPA Report 660/2-
74-077, EPA, Washington, D.C., (1974).
16. Khare, M. and Dondero, N.C., "Fractionation and Concentration
from Water of Volatiles and Organics on High Vacuum Systems:
Examination of Sanitary Landfill Leachate," Environ. Sci, Technol.,
11(8), 814, (1977).
17. Stegmann, R., "Qualitat von Sickerwasser aus Mulldeponien," Seminar
2, 1974, Stadterinigung Kg, Edelhoff, 5860, Iserlohn, Germany,
(1976).
18. Talbot, R., Water Chemistry Laboratory, University of Wisconsin,
Madison, Wisconsin, personnel communication.
130
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APPENDIX
10]
FACTOR '
0 20 40 60 80 100
% WATER IN WASTE (wet weight)
Explanation:
7)Concept is to use ten times normal strength synthetic leachate concentrate,
reducing the amount of distilled water to dilute the concentrate by the
amount of moisture in the waste.
2) Grams dry waste = ml. of lOx cone, synthetic leachate.
3) Volume (mis) of distilled water to dilute cons. (lOx) synthetic leachate =
volume cone. (lOx) synthetic leachate times the factor plotted above.
4) Example: Desired mix = 60 gr. dry waste and 600 ml. synthetic leachate
media (1:10 ratio). Amount lOx concentrated synthetic leachate = 60 mis;
amount distilled water for wet waste at 50% moisture content = 60 x 8 = 480 mis
(8 is factor plotted above).
5) For Procedure R, replacing the waste, add an amount in ml. of lOx cone.
synthetic leachate equal to 1/9 the weight of moisture added in the wet
waste each time waste is added. Continuing example (4 above), if waste
is replaced for elution 2, add 60/9 or 6.7 ml. lOx cone, synthetic leach-
ate to counter the dilution by the moisture in the wet waste.
*For % water in waste > 90%, use required amount wet waste plus mis. lOx
cone, synthetic leachate = grams dry waste only.
Figure A-l. Correction of the moisture content when using the synthetic
lerrhate. 131
-------
SERIES B2. MUNICIPAL WASTE
CO
a i ]DIST.
B2]H2Oe
• 3)COPPER SULFATE, A4)THYMOL.* 5)SILVER NITRATE
REDOX, mV
O 8 O™
300- •
225
I50--
75-
3 DAYS
Figure A-2 Test B2 on the effects of various biologically inhibiting agents on
leaching of municipal wastes. (See text for procedure.) Redox - J
pH.
-------
SERIES 82, MUNICIPAL WASTE
_ MMHOS/CM-x I03
.8--
I*
o
O
o
.2--
COPPER SULFATE
2
DAYS
Figure A-3. Test 82 on the effects of various biologically
inhibiting agents on leaching of municipal
wastes. Specific conductance.
133
-------
DIST
SERIES B2, MUNICIPAL WASTE
« 3) COPPER SULFATE, *4)THYMOL, *5)SILVER NITRATE
i2y.
COO, ppm
1500
2OOO- •
1500- •
IOOO--
500- =
Mg, ppm
15-•
!0
Mg, ppm
20 T
IS
10
0
DAYS
Figure A-4. Test 82 on the effects of various biologically
inhibiting agents on leaching of municipal wastes.
COD, Mgs and Fe.
134
-------
I? DIST.
•\ H2°'
SERIES 82, MUNICIPAL WASTE
• 3)COPPER SULFATE. *4)THYMOL. *5)SILVER NITRATE
75
SO-
45
30
15-•
Zn, pprn
Pb, ppm
,0.0?' ppm
7.5--
5.O--
2.5--
Cu. ppm
6-Or
4.5"
3.O--
1.5-'
-I
3 DAYS
Figure A-5. Test B2 on the effects of various biologically
inhibiting agents on leaching of municipal
wastes. Zn, Pb, K, Cu.
135
-------
to
en
u
J 2
REOOX. mV
40OT
300 •
200--
SERIES 64, MUNICIPAL WASTE
• 3) COPPER SULFATE. * 4) THYMOL, A 5) SILVER NITRATE
-50 A
100-•
PH
8T
6
DAYS
Figure A-6. Test B4 on the effects of various biologically inhibiting agents on leaching
of municipal wastes. (See text for procedure.) Redox and pH.
-------
SERIES B4, MUNICIPAL WASTE
20
^MHOS/CM xlO'
6
4
>
p 2 •
s
Q
O
O |.
0.6
0.4
0.2
O.I
/1-.THYMOL
I 2 3
DAYS
Figure A-7. Test 84 on the effects of various biologically
inhibiting agents on leaching of municipal
wastes. Specific conductance.
137
-------
SERIES 84, MUNICIPAL WASTE
0 I/DIST. ®3)COpPER SULFATE,*4)THYMOL,,A5)SILVER NITRATE
600
K.ppm
4OOT
450
30O
150
20O
100
0
0 ppm
4
Cd, ppm
0.4-r
0.3--
O.2-°
0.!
0.025
DETECTION LIMITS
DAYS
Figure A-8, Test 84 on the effects of various biologically
inhibiting agents on leaching of municipal
wastes. Na, K, Cu, Cd.
*A11 points below detection limit are approximate.
138
-------
SERIES 84, MUNICIPAL WASTE
° '( P'S,J- « 3) COPPER SULFATE.* 4) THYMOL, * 5) SILVER NITRATE
"23 H20<
Mg, ppm
22.5--
15.0- •
7.5--
•"MULTIPLY SCALE
VALUE x 10 **
60 T
50--
40-.
30--
Zn.ppm
20--
10-•
200
ISO--
I2O--
8O-.
40"
COO, ppm
I2.000T
10,000- •
8.000- •
6,000--
4,000- •
2.000-
DAYS
Figure A-9. Test B4 on the effects of various biologically
inhibiting agents on leaching of municipal
wastes. Fe, Mg, Zn, COD.
139
-------
S05-r COD
10 --
10"
SUMMARY SERIES B28 B38 84
LEGEND* •B2lmg/kg8 ABSppm, "84
l04-rK JO3-
DIST. COPPER THYMOL SILVER DIST. COPPER THYMOL SILVER 0!ST
H2°
SULFATE
NITRATE H20 SULFATE
NITRATE H2O
COPPER THYMOL SILVER
SULFATE NITRATE
Figure A-10. Comparison of tests B2, B3S and B4. (See text for] procedure.)
COD, K8 Mg. I
-------
SUMMARY SERIES B2, B3, B4
LEGEND' «B2£mg/kg, A 83 ppm, • 84 £mg/kg
I02--
10'--
1.0
OIST. COPPER THYMOL SILVER DIST. COPPER THYMOL SILVER
H20 SULFATE NITRATE HgO SULFATE NITRATE
Figure A-11. Comparison of tests 82, 83, and 84. (See text
for procedure.) Fe, Zn.
141
-------
PH
10-r
SERIES PI, FLY ASH, DISTILLED HgO
*2 HRS, »24 MRS. A 48 HRS, »72 MRS
REDOX, mV
120
6-.
5«—4=
H5i
No, ppm
16 r
12-
8--
Figure A-12.
ELUTIONS
Test PI on the effect of time per elution using
procedure R on fly ash with distilled water.
(See text for procedure.) pH, Redox, Na, K.
142
-------
CO
2.5r
2.0 '
1.5
1.0 -
0.5
ppm
DIST.
SERIES PI, FLY ASH
• 2HRS. »24 HRS.A48HRS. • 72 MRS
COD , ppm
COINCIDENT VALUES
D.ST. H20
Mg, ppm
"SYNTHETIC LEACHATES
OOAQ DUPLICATES
16 •
12 -
8 -
4 •
123 123 123
ELUTIONS
Figure A-13. Test PI with fly ash and distilled water (Mg and COD) and synthetic leachate (Mg).
-------
SERIES Pi, FLY ASH, SYNTHETIC LEACHATE
«> 2 HRS. • 24 HRS, * 48 MRS, • 72 MRS, Ooao DUPLICATES
8
pH
ALL OTHER VALUES
REDOX.mV
15-
-30--
-45"
Zn, ppm
OJ5-
0.6O
0.45 • •
0.30
0.15
K.ppm
15 T
It--
9--
6
I 2 3 ELUTIONS I 2
Figure A-14. Test PI with fly ash and synthetic leachate.
pHs Redox, Zns and K.
144
-------
SERIES PI, FLY ASH, O.I N H2S04
*2HRS, • 24 HRS. A 48 HRS, "72 HRS
PH
fi 1MIC
4--
3--
2--
REDOX,
500 T
40O--
300 ••
200 •
MOO ••
0
Na, ppm
40r
30--
20"
IO--
3 ELUTIONS I
Figure A-15. Test PI with fly ash and 0.1N H?SO.. pH, Redox,
Na, K.
145
-------
SERIES PI, FLY ASHf O.I N H2S04
*2HRS, • 24 MRS, A 48 MRS, o 72 HRS
ppm
0.8
0.6
0.4
0.2'
O.09-
0
ia§T
100
75
50
25
DETECTION LIMIT
-f 1 !
Mg,ppm
30-r
22.5 - •
15
7.5
COO, ppm
200*
I50--
100
1
3 EUUT10NS
Figure A-16. Test PI with fly ash and 0.1N H,SO
Cu, Fe, Mg, COD. ^
146
-------
SERIES PI, PAINT WASTE, DISTILLED
* 2 HRS, »24 HRS, A48 HRS, a 72 HRS
pH REDOX.mV
IOT
9--
fi " •
6-
I20T
-40-.
-80 -"•
Na.ppm
375 T
30.0-'
22.5-.
15.0- •
7.5
K, ppm
2.5-r
3 ELUTIONS
0.5 ••
0.0-4 - •
Figure A-17. Test PI on the effect of time per elution using
procedure R on paint waste with distilled water.
pH, Redox, Na, K.
*
Points below detection limit are approximate.
147
-------
Mg, ppm
12.5 T
SYNTHTIC LEACHATE
^o DUPLICATES
SERES PI, PAINT WASTE
*2HRS, «24HRS. *48 HRS,« 72 HRS
Zn, ppm
0.5 T
DIST. H20
D COINCIDENT VALUES
0.4 ••
3.3"
0.2
0.1-•
COD, ppm
4500,-
Mg. ppm
3750
3000- =
2250
I5OO
750
DIST. H20
O COINCIDENT VALUES
DIST. H20
COINCIDENT
VALUES
IvS"
H
3 ELUTIONS
Figure A=18. Test PI with paint waste and distilled water
(Zn, COD, Mg) and synthetic leachate (Mg).
148
-------
SERIES PI, PAINT WASTE, SYNTHETIC LEACHATE
2 HRS. • 24 HRS. A 48 HRS. » 72 HRS, O O a D DUPLICATES
PH
6
5--
A. c
3-°
2 •
REDOX.mV
75T
50-
25-'
-25-•
-50 4-
Zn, ppm
20T
K, ppm
4.5'- •
3.O--
1.5-•
3 ELUTIONS I
Figure A-19. Test PI with paint waste and synthetic leachate.
pH, Redox, Zn, and K.
149
-------
SERIES PI, PAINT WASTE, 0.1 N Hg
^2 HRS, «24 HRS, * 48 HRS, B72 HRS
PH REDOX.rrtV
§00
4
3
2--
400
300- •
200'
100
Me. ppm
25 T
20--
5--
0
K.ppm
2.5-r
2.0--
L5--
1.0
0.5
j
2 3 ELUTIONS I
Figure A-20. Test PI with paint waste and 0.1N H?SCL. pH,
Redox, Nas K. c
150
-------
SERIES P!, PAINT WASTE, O.I N
*2 HRS, «24 MRS. * 48 HRS. » 72 HRS
Zn, ppm COD. ppm
25r 3750T
20-•
15--
10- •
3000"
2250- •
1500- •
750-•
Mg. ppm
IOT
Fe, ppm
5-r
4..
3--
2 •
0«—I-
3 ELUTIONS I
Figure A-21. Test PI with paint waste and 0.1N FLSC
Zn, COD, Mg, Fe. ^
151
-------
SERIES PV I, FLY ASH
150 mL OF H20+ 15 g/L NaHS03 +> Co 4> 21.5 g FLY ASH, (1-7)*
REFILLED EACH DAY WITH 150 mL OF HgO
160-r I6O-T
140- •
I20-
IOO--
en
80
i 60'
40'
20--
I
2
DAYS
3
!40
I2O —
100-
X
V)
80+
£6O
N
4O
20-
1
2
DAYS
TEST NO. AGITATION RVALUE LINE TEST NO. AGITATION RVALUE
17 SHAKE .5<9^
-------
SERIES PVI, FLY ASH
150 mL OF H£0 + 15 g/L NaHSOg -I- Co-f 2l.5g FLY ASH. (1-7)*
REFILLED EACH DAY WITH ISO mL OF HgO
20T 20 T
x
v>
<
u.
X
Q
O
o
E
W
15-•
IO- •
TEST NO. AGITATION RVALUE LINE TEST NO. AGITATION £
'] SHAKE .5<9*
-------
SERIES PV2 PAPER MILL SLUDGE, (N)
REDOX
-20
-60-
-80
+ 40
pH
9->
8
1
2
TEST NO.
I •__—__ 20"C
2 •——- 33eC
3 n—— 20" C
4 o»-— 33°C
pH
10
9
—+
3 DAYS
AGITATION
INTERMITTENT
SHAKE
8
TEST NO. AGITATION
5 A STIR
6 *• SWING
Figure A-24. Test PV2 using different agitation techniques
on papermill sludge with distilled water. (See
test for procedure.) Redox, pH.
154
-------
SERIES PV2 PAPER MILL SLUDGE, (N)
CONDUCTIVITY
i.O j
0.8--
0.6-
CO
o
x
"b
0.4 ••
0.2- -
o
o
O.I
TEST NO.
I * 20°C
2 • 33°C
3 • — 20° C
4___— 3300
2 3
AGITATION
INTERMITTENT
SHAKE
DAYS
I
TEST NO.
2 3
AGITATION
STIR
SWING
Figure A-25.
Test PV2 using different agitation techniques
on papernrin sludge with distilled water.
Specific conductance. ~
155
-------
SERIES PV2 PAPER MILL SLUDGE (N5
K.ppm 5"mg K/kg PMS
•* 80 T
4
3--
2
60--
40--
20-
0
500-r
400--
300- •
too--'
100
0
COD, ppm
I I
! " 2
TEST NO.
2
3
7 21 9 COD/kg PMS
6
5 ••
3-°
,a
-- 20"C
4 <>-_„_ 33<>c
3 DAYS
AGITATION
INTERMITTENT
SHAKE
I 2 3
TEST NO. AGITATION
5 *— • STIR
6 O- SWING
Figure A-26. Test PV2 using different agitation techniques on
papermill sludge with distilled water, K, COD.
156
-------
SERIES PV3, MUNICIPAL REFUSE
TEST NO. AGITATION
I INTERMITTENT
REDOX, rnV 3~ STIR REDOX. mV
5- SHAKE, 20° C
150
7 SHAKE, 33°C
0 POISONED
100-
50-
-50-•
-1OO
-1501
IOO--
50--
-5O"
-IOO--
-150- •
I2r
IO--
8--
6
12 T
IO-. o
g..
6
3 DAYS
Figure A-27. Test PV3 using different agitation techniques
on shredded municipal refuse with distilled
water. (See text for procedure.) Redox, pH.
157
-------
SERIES PV3, CONDUCTIVITY x ICT ^MHOS/CM
MUNICIPAL WASTE
3-
.3-
.2-
I
TEST NO. AGITATION
I _____ INTERMITTENT
3 — • STIR
5 „-__ SHAKE, 2p"C
7 __,„_„ SHAKE, 33*C
o POISONED
.075-
DAYS
Figure A-28. Test PV3 using different agitation techniques
on shredded municipal refuse with distilled
water. Specific conductance.
158
-------
ppm
SERIES PV3 MUNICIPAL WASTE
mg Fa / kg M.W.
\
60--
45--
30
15-•
AGITATION
INTERMITTENT
15
DAYS I
21 mg K/kg MW.
750
600 ••
450-
3OO-
I5O-
— --o
DAYS I
Figure A-29. Test PV 3 using different agitation tech-
niques on shredded municipal refuse with
distilled water. Fe, K.
159
-------
SERIES PV3, MUNICIPAL WASTE
K, PPM
E rag K/kg M.W.
TEST NO. AGITATION 5OO
INTERMITTENT
STIR
SHAKE,20eC
SHAKE,33«C 4QO-•
3OO
20O
100-•
Mn. PPM
1.6 T
O.8--
0.4 ••
Mn/kg M.W.
10-•
3 DAYS
Figure A-30.
Test PV3 using different agitation techniques on
shredded municipal refuse with distilled water.
K (repeat), Mn.
160
-------
Zn ppm SERIES PV3 MUNICIPAL WASTE
TEST NO. AGITATION
| 1- | INTERMITTENT
3 • I
4 o-I S™
I 0~"1 SHAKE, 20°C
7- £-| SHAKE, 33»C
8 o *
o POISONED
Hmg
200
Zn /kg M.W
I60--
120 •
80
40--
DAYS I
DAYS I
Figure A-31. Test PV3 using different agitation techniques
on shredded municipal refuse with distilled
water. Zn.
161
-------
BODg ,PPM
ioooT
BOO
800
700-
600-
500
400
300
20O
!OO-°
SERIES PV3, MUNICIPAL WASTE
rg BODt/kg M.W.
IOr °
TEST NO. AGITATION
INTERMITTENT
___, STIR
SH'AKE^ZO'C 9-.
SHAKE, 33« C
o POISONED
\ -EE
7--
6-
4..
3 DAYS
Figure A-32. Test PV3 using different agitation techniques
on shredded municipal refuse with distilled
water. BOD.
162
-------
SERIES PV3, MUNICIPAL WASTE
COD, ppm £gCOD/kg M.W.
1400T
1200" .\ 5__ SHAKE ,20-C 18-8-'
1000- •
800-
600-
400-
200--
TEST NO. AGITATION
I - - INTEMITTENT
3__ -- - STIR
' T
\i \
7 --- SHAKE, 33°C
14.0 •
11.2- •
8.4--
5.6--
2.8
3 DAYS
Figure A-33. Test PV3 using different agitation techniques on
shredded municipal refuse with distilled water.
COD.
163
-------
IOOO
800"
600--
400-
20O'
ppm
SERIES PV3, MUNICIPAL WASTE
TEST NO.
I A
3 •
5 •
7 •
AGITATION
INTERMITTENT
STIR
SHAKE, 20° C
SHAKE, 33* C
NUMBER BY SYMBOL IS
DAY OF TEST
BODg' COD ~.62
200
Figure A-34.
6OO
COD, ppm
IOOO
I4OO
Test PV3 using different agitation techniques
on shredded municipal refuse with distilled
water. Comparison of BOD and COD concentrations.
164
-------
SERIES PV4
AGITATION' • INTERMITTENT. • SHAKER. A ROTATING DISK
PH
HT
10-•
8
•PAPER MILL SLUDGE
SLUDGE CLARIFIES
10
8--
FLY ASH.AA
PAINT WASTE
3 DAYS
REDOX.rrft/
40 T
-40--
-80-
-J20--
REDOX, mV
40T
-4O- •
-80-•
-120- •
H60-1-
Figure A-35.
Test PV4 comparing different agitation tech-
niques on four wastes with distilled water.
(See text for procedure.) pH and Redox.
165
-------
SERIES PV4, CONDUCTIVITY
AGITATION* • INTERMITTENT, • SHAKER, A ROTATING DISK
PAPER MILL SLUDGE FLY ASH (AA)
SLUDGE CLARIFIER -----PAINT WASTE
^MHOS/CM x 10
1.0
^MHOS/CM x
1.0-
Figure A-36. Test PV4 comparing different agitation tech-
niques on four wastes with distilled water.
Specific conductance.
166
-------
SERIES PV4
20-r
AGITATION- "INTERMITTENT, «SHAKER, A ROTATING DISK
No. ppm NCI, ppm
10-•
5 •
V
_A
PAINT WASTE
20T
15- •
10-
5..
FLY ASH, AA
20T
15-
10-
5--
Ha, ppm
PAPER MILL SLUDGE
-I f
20T
15-
10--
5--
No, ppm
SLUDGE CLARIRER
\
\
3 " DAYS
Figure A-37. Test PV4 comparing different agitation tech-
niques on four wastes with distilled water. Na.
167
-------
SERIES PV4
AGITATION- • INTERMITTENT, • SHAKER, A ROTATING DISK
Cu, ppm Zn, ppm
0.2 5-r
0.20- •
0.15-
0.10 •
0.05- •
PAPER MILL SLUDGE
CTION UMIT
« *
0.5
0.4- •
0.3
0.2 •
PAINT WASTE
\\
0.60
0.45-•
F«, ppm
O.I5--
\
. SLUDGE
\ CLARIFIER
\
0.30-f $-^ \
\
V-
0.02
0.0(5- -
O.OI • •
O.O05- •
2n, ppm
SLUDGE CLARIFIER
._. ,-A
— x
3 DAYS
Figure A-38. Test PV4 comparing different aqitation tech-
niques on four wastes with distilled water.
Cu, Zn, Fe.
*A11 points below detection limit are approximate.
168
-------
SERIES PV4
AGITATION' • INTERMITTENT, • SHAKER, ^ROTATING DISK
COO, ppm
100 T
75-.
50-
25-
FLY ASH. AA
FLY ASH. AA
• ' 3.0--
PAPER MILL SLUDGE
Mg. ppm
PAPER MILL SLUDGE
DAYS
4O--
Figure A-39.
Test PV4 comparing different agitation tech-
niques on four wastes with distilled water.
COD, K, Mg.
169
-------
SERIES PV4
AGITATION' • INTERMIT TENT, e SHAKER, * ROTATING DISK
500
400-
300
200
100-
COO,ppm
0
—— SLUDGE CLARIFIES
_..._ PAPER MILL
SLUDGE
^
Mg, ppm
SLUDGE
CLARIFIER
-PAINT
WASTE
SOOOi
COO, ppm
—— PAINT WASTE
4000
3000- •
2000
1000
\\
\\
X
K, ppm
2.0j _ _ _ PAINT WASTE
— SLUDGE
CLARIFIES
1.5-
1.0- •
0.5
DAYS
0.
Figure A-40. Test PV4 comparing different agitation tech-
niques on four wastes with distilled water.
COD, Mg, K.
170
-------
SERIES PV4, AGITATION PROCEDURE COMPARISON
CUMULATIVE RELEASE AFTER 3 DAYS. LIQUID- HO
I03-
.. I. PAPER MILL SLUDGE, N
.. 2. SLUDGE CLARIFIER
3. PAINT WASTE
4. FLY ASH, AA
tr
Ul
liozdr
to
to
o
to
2 4-
O T
cc
h
3 l
i-
AGITATION
• SHAKER
" ROTATING DISK
Figure A-41.
10 Emg/kg
AGITATION- INTERMITTENT
Test PV4 comparing the cumulative release of
all measured parameters after 3 elutions using
the rotating disc and intermittent shaking agi-
tation techniques.
171
-------
pH
SERIES PV5
AGITATION' » INTERMITTENT, « SHAKER, A ROTATING DISK
B-r
6-
4-
2--
PAPER MILL
SLUDGE,N —
MUNICIPAL
WASTE—-
PH
ft „,
PAPER MILL.
SLUDGE,EPA-
SLUDGE N -
CLARIFIER
2.5-
2..Q--
I.S-
1.0-
PH
PH
PAINT WASTE
FLY ASH, AA
DAYS
Figure A-42.
Test PV5 comparing different agitation tech-
niques on several wastes with 0.1N HgSO^.
(See text for procedure.) pH.
172
-------
SERIES PV5
AGITATION' H INTERMITTENT, • SHAKER, ^ROTATING DISK
REDOX. mV REDOX, rnV
500T 500T
,"' / PAINT
. *' >' WASTE
400-
300
200--
IOO--
PAPER MILL
SLUDGE, N
PAPER MILL
SLUDGE, EPA
'--«-
1 - 1
400
300--
200-•
10 0--
i*
H
11
I i
,'!
/ / FLY ASH. AA
SLUDGE
CLARIFIER
DAYS
Figure A-43. Test PV5 comparing different agitation tach-
niques on several wastes with 0.1N H2S04-
Redox.
173
-------
SERIES PV5, CONDUCTIVITY
AGITATION- • INTERMITTENT. « SHAKER, A ROTATING DISK
PAINT VW8.STE FLY ASH (AA)
PAPER MILLSLUDGE, N. ———— MUNICIPAL WASTE
X IO4 ^MHOS/CM
AT
.3
.3
IO4
SLUDGE CLARIFIER
DAYS
.3
Figure A-44. Test PV5 comparing different agitation tech-
niques on several wastes with 0.1N ^SO^.
Soecific conductance.
174
-------
SOT
60-
4O--
20-
SERIES PV5
AGITATION- •INTERMITTENT, • SHAKER, * ROTATING DISK
No, ppm No, ppm
FLY ASH.AA —
"PAPER MILL
SLUDGE, EPA
>^ "D-
40 T
3O- -,
20--
10"
•--o
PAINT WASTE
No. ppm
I5OT
120- ^. PAPER MILL
SLUDGE.N
SO-
60-
30"
Na, ppm
750T
SLUDGE CLARIFIER
MUNICIPAL WASTE
600- •
45O- •
30O ••
ISO-
oL+
DAYS
Figure A-45
Test PV5 comparing different agitation tech-
niques on several wastes with 0.1N H^O^. Na.
175
-------
400
SERIES PV5
ASITATIONi •INTERMITTENT, •SHAKER, A ROTATING DISK
COO, ppm COD, ppm
400i
SLUDGE CLARIFIER
300
200-•
100- •
PAPER MILL
SLUDGE. EPA
300--
200-•
100
FLY ASH, A A
COD, ppm
€000
PAINT WASTE
PAPER MILL
SLUDGE, N -
4500
3000
I5OO
COD, ppm
SOOO-r
MUNICIPAL WASTE
4500- •
3000- •
I5OO
DAYS
Figure A-46.
Test PV5 comparing different agitation tech-
niques on several wastes with (LIN HgSO^. COD.
776
-------
6.0r
4.5
3.0
SERIES PV5
AGITATION- "INTERMITTENT, • SHAKER, * ROTATING OISK
K, ppm K, ppm
PAINT WASTE
80 T
60-
40"
20-•
FLY ASH.AA
K, ppm
lO.Or
.SLUDGE CLARIFIER
7.5--
6.0-•
2.5 •
PAPER MILL SLUDGE
•-^ (PMS).EPA
MUNICIPAL WASTE
Figure A-47. Test PV5 comparing different agitation tech-
niques on several wastes with 0.1N H2S04- K.
177
-------
SERIES PV5
AGITATION' "INTERMITTENT, • SHAKER, * ROTATING DISK
1000
800
6OO- •
400-
200--
Mg, ppm
PAPER MILL
SLUDGE,N
Mg. ppm
FLY ASH, AA
5--
400r
300--
2OO
1OO--
ngc ppm
SLUDGE CLARIFIER
400T
300"
200-
IOO--
Mgc ppm
MUNICIPAL WASTE
3 DAYS
Figure A-48. Test PV5 comparing different agitation tech-
niques on several wastes with (LIN H-SO. Mg.
178
-------
SERIES PV5
AGITATION' • INTERMITTENT, »SHAKER, A ROTATING DISK
Fe. ppm Fe, ppm
25T
20"
15--
PAPER MILL SLUDGE.N
10--
25T
20-
15- •
10-
PAINT WASTE •
RM.S., EPA
<$>-
Fa, ppm
200T
150-
IOO--
50--
FLY ASH. AA
Fe, ppm
500T
375-
250--
125- •
DAYS
Figure A-49. Test PV5 comparing different agitation tech-
niques on several wastes with 0.1N H,,S04. Fe,
179
-------
Cu, ppm
I 5"T°
SERIES PV5
AGITATION- • INTERMITTENT, »SHAKER, A ROTATING DISK
Zn, ppm
PAPER MILL
SLUDGE,N
MUNICIPAL
WASTE—--
FLY ASH. A A
1.5
1.2
Cu, ppm
DETECTION UMIT
PAINT
, WASTE-
.MUNICIPAL
vWASTE —
DAYS
Figure A-50. Test PV5 comparing different agitation tech-
niques on several wastes with 0.1N ^SO^. Cu and Zn,
*
Approximate value.
180
-------
ppm
SERIES PV5
IOOT
PAPER MILL
SLUDGE.N
AGITATION . ' -
• INTERMITTENT
• SHAKER
A ROTATING DISK
X !
DETECTION LIMIT*
Cd, ppm
FLY ASH. AA
Figure A-51. Test PV5 comparing different agitation tach-
niques on several wastes with 0.1N H?SCL.
Pb and Cd.
*A11 points below detection limit approximate.
181
-------
SERIES PV5, AGITATION PROCEDURE COMPARISON
£mg/kg CUMULATIVE RELEASE AFTER 3 DAYS
I. PAPER MILL SLUDGE, N
2. SLUDGE CLARIFIER
3. PAINT WASTE
4. FLY ASH, AA
5. MUNICIPAL WASTE
AGITATION
• SHAKER
• ROTATING DISK
10
10
Figure A-52.
10'
/kg
AGITATION* INTERMITTENT
Test PV5 comparing the cumulative release of
all measured parameters after 3 elutions using
the rotating disc and intermittent shaking agi-
tation techniques.
182
-------
pH
SERIES Rl FLY ASH
o I« 100 O MO
o l« 20 * 1-7
a f'10 x 1-4
4..
3--
•8-
SYNTHETIC LEACHATE
O.I N H2S04
MARCH 22
24
28
Figure A-53.
Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with fly
ash and synthetic leachate and 0.1N HSO,. pH.
183
-------
00
pH
§T
4
3 * ~
2 -
SERIES RI - FLY ASH
SOLID-LIQUID RATIOS'80
A A A
4&A*A AAAAAA AAAAA A
SYNTHETIC LEACHATE
A COINCIDENT VALUES
A
A
NEW PROBE
I -
O.IN
inn H i i ij i in i i u n 1111 in H h
+
f
3/22
4/1
4/20 4/25 5/2 5/9 5/16 5/23
Figure A-54. Expansion of Figure A-53 for a solid-liquid ratio of 1:10 over more elutlons.
Duplicate runs.
-------
SERIES RI FLY ASH
O l« 100 O I' 10
a |. 20 ? |. 7
A !• 10 x I'4
REDOX, mV
I0.1N H2S04
SYNTHETIC LEACHATE
X
?
&
o
a
MARCH 22
28
Figure A-55.
Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with fly
ash and synthetic leachate and 0.1N HUSO.. Redox.
185
-------
00
0>
REDOX. mV
50O~t-
400--
30O--
200 --
100
-100
SERIES R! - FLY ASH
SOLID-LIQUID RATIO MO
O.I N H2S04
t */<
I
3/22 4/1
—I i i i i i i i 11 h M i i I (
COINCIDENT VALUES
4/2O 4/25 5/2 5/9 5/16 5/23
H-l -i A * !
Figure A-56.
4-
SYNTHETIC LEACHATE
Expansion of Figure A-55 for a solid-liquid ratio of 1:10 over more elutions,
Duplicate runs.
-------
Na, ppm
20-r
16
12--
8--
4..
SERIES R! FLY ASH
0.! N H2S04
• MOO * I« 10
• I«20 v |. i 7
|MO x Is 4
MARCH 22
24
28
Figure A-57. Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with fly
ash and 0.1N H0SO.. Na.
187
-------
CO
CO
No, ppm
20-r
16--
12
8--
*
A,
3/22
SERIES RS FLY ASH
O.I N H.
k« SOLID-LIQUID RATIO HO
' A COINCIDENT VALUES
&
4/1
4/20 4/25 5/2 5/9
5/16 5/23
Figure A-58. Expansion of Figure A-57 for a solid-liquid ratio of 1:10 over more elutions,
Duplicate runs.
-------
SERIES Rl FLY .ASH
O.I N
MARCH 22
Figure A-59.
Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with fly
ash and 0.1N H^SO.. K.
L. T1
189
-------
K9ppm
7§T
60--
45--
30--
15--
SERIES RI FLY ASH
OJN H2S04
SOLID-LIQUID RATIO NO
A COINCIDENT VALUES
1
f
nil ninii mi iinnii nn in
3/22
4/1
4/20 4/25 5/2
5/9
5/16
5/23
Figure A-60. Expansion of Figure A-59 for a solid-liquid ratio of 1:10 over more elutions
Duplicate runs.
-------
SERIES
Mg, ppm
60-r
50-
40-
30-
20-
10"
Rl
O.I N
• moo
B 1*20
4 MO
FLY ASH
H2S04
* ino
V M7
x 1*4
MARCH 22
24
Figure A-61.
Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with fly
ash and 0.1N HS0. Mg.
191
-------
ro
Mg, ppm
40-r
30
20--
10
SERIES RS FLY ASH
0.1 N H£S04
A COINCIDENT VALUES
SOLID-LIQUID RATIO I'10
8Si8B8S8!8ii8III8Sii
3/22
4/8
4/20 4/25 5/2
5/7
5/16
5/23
Figure A-62. Expansion of Figure A-61 for a solid-liquid ratio of 1:10 over more elutions
Duplicate runs.
-------
SERIES Rl FLY ASH
Cu, ppm
0.3-r
0.2--
O.I--
O.I N H2S04
OhlOO
DI • 20 V 117
Al'IO xh4
MARCH 22
•i 1
24
28
Figure A-63.
Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with fly
ash and 0.1N H-SO.. Cu.
193
-------
SERIES RI FLY ASH
OJ N H2S04
SOLID-LIQUID RATIO I'10 •
Cu» PPm A COINCIDENT VALUES
0.3
AA A A
0.2+ *S * *
OJ
A A . * A A
•A A« A A i •
A • • * A A I
siinmiiiimmmnmiin 1 1 H™—H h-
3/22 4/1 4/20 4/25 5/2 5/9 5/16 5/23
Figure A-64. Expansion of Figure A-63 for a solid-liquid ratio of 1:10 over more elutions.
Duplicate runs.
-------
SERIES Rl FLY ASH
COD,ppm
240-r
200--
I60--
I20--
80--
40--
0.1 N H2S04
• I'lOO *MO
• l«20 ^!.«7
I«IO x l«4
MARCH 22
Figure A-65. Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with fly
ash and 0.1N H-SO.. COD.
195
-------
IO
cr>
COD, ppm
240-r
200--
160--
S20--
80--
40-
SERIES Rl FLY ASH
0.1 N H2S04
SOLID-LIQUID RATIO MO
*
•
A
I
COINCIDENT VALUES
i I II I 111 11111 Ml I I I 111 I if I II 11 ^
-f-
3/22 4/1 4/20 4/25 5/2 5/9 5/16 5/23
Figure A-66. Expansion of Figure A-65 for a solid-liquid ratio of 1:10 over more elutions,
-------
K,ppm
20-r
15--
10--
•5--
SERIES RI FLY ASH
SYNTHETIC LEACHATE
• HOO * 1 = 10
1'20
MARCH 22
24
28
Figure A-67.
Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with fly
ash and synthetic leachate. K.
197
-------
10
00
15 T
10- •
5- •
*
A «
SERIES Rl FLY ASH
SYNTHETIC LEACHATE
SOLID-LIQUID RATIO HO
& COINCIDENT VALUES
AAtt
i i i n i n i 1111 n n 811111 n n i n
A
A
A,
3/22
4/1
4/20 4/25 5/2
5/9
5/16
5/23
Figure A-68. Expansion of Figure A-67 for a solid-liquid ratio of 1:10 over more elutions.
Duplicate runs.
-------
Mg, ppm
20 T
16"
12--
8--
4--
SERIES Rl FLY ASH
SYNTHETIC LEACHATE
ohIOO * I«IO' '
• 1=20 Th7
10 x h4
MARCH 22
Figure A-69.
Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with fly
ash and synthetic leachate. Mg.
199
-------
ro
o
o
, ppm
12 T
8--
4--
A
•
SERIES Rf FLY ASH
SYNTHETIC LEACHATE
A COINCIDENT VALUES
SOLID-LIQUID RATIO !' 80
*
iiiiiiiiiiiimiMiiirmiiiii i-
3/22
4/1
4/20 4/25 5/2
5/9
5/16
5/23
Figure A-70. Expansion of Figure A-69 for a solid-liquid ratio of 1:10 over more elutions
Duplicate runs.
-------
SERIES R! FLY ASH
SYNTHETIC
LEACHATE
0.8--
0.6--
0.4-
0.2-
0.018-t
MARCH 22
Figure A-71. Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with fly
ash and synthetic leachate. Zn.
201
-------
SERIES Rl FLY ASH
o
IM
Zn, ppm
I.Or
0.8 -
0.6 -
0.4 -
0.2
0.018--
A.
SYNTHETIC LEACHATE
SOLID-LIQUID RATIO 1*1
A COINCIDENT VALUES
iin nn
4-
t
3/22
4/S
4/20 4/25 5/2
5/9
5/16
5/23
Figure A-72. Expansion of Figure A-71 for a solid-liquid ratio of 1:10 over more elutions,
Duplicate runs.
-------
PH
5T
SERIES Rl PAINT WASTE
oi«ioo oi« 10
o|.20 *!• 7
^I'10 x |. 4
4..
SYNTHETIC LEACHATE
I-
O.I N H2S0
MARCH 22
24
28
Figure A-73.
Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with paint
waste and synthetic leachate and 0.1N H2S04. pH.
203
-------
SERIES RI PAINT WASTE
SOLID-LIQUID RATIO MO
5-r
o • *
2--
I --
AV AAAAA i
AA&AA A A A
SYNTHETIC LEACHATE
A COINCIDENT VALUES
WEAK ACID
.
0.1 N H2S04
11 MI 1111111 ii u nm ii inn 11
+
+
NEW PROBE
A
A
+
+
3/22
Figure A-74.
4/1
4/20 4/25 5/2 5/9 5/16 5/23
Expansion of Figure A-73 for a solid-liquid ratio of 1:10 over more elutions,
Duplicate runs.
-------
SERIES Rl PAINT WASTE
o|.|00.
a 1-20
I- 10
300--
200-•
100- •
0-- I
SYNTHETIC LEACHATE
-IOO
MARCH 22
24
28
Figure A-75.
Test Rl using procedure R to evaluate different
solid-liquid ratios over five elutions with
paint waste and synthetic leachate and O.IN H^S
Redox. 2
205
-------
INJ
o
0>
REDOX, mV
400T A
300
200--
IOO--
0
I
SERIES Rl PAINT WASTE
SOLID-LIQUID RATIO HO
O.i N H«S0
A COINCIDENT VALUES
f *
3/22 4/1
|i illIJ>8 8 H I II I 8 It
4/20 4/25 5/2 5/9 5/16 5/23
nnn 11 -i———I 4-
•100-L
Figure A-76.
SYNTHETIC LEACHATE
Expansion of Figure A-75 for a solid-liquid ratio of 1:10 over more elutions,
Duplicate runs.
-------
SERIES Rl PAINT WASTE
Na,ppm O.IN HOSO.
62.5T
50.0-
37.5-
25.0-
I2.5--
MARCH 22
Figure A-77. Test Rl using procedure R to evaluate different
solid-liquid ratios ovar five elutions with paint
waste and 0.1N HS0. Na.
207
-------
ro
O
00
No, ppm
62.5T
50.0--
37.5--
25.0-•
12.5-•
SERIES Rl PAINT WASTE
OJ N H2S04
SOLID LIQUID RATIO HO
COINCIDENT VALUES
,
ill! !l HI III Hi I ill lilli I!H
3/22
4/1
-f
4/20 4/25 5/2
-4— 1- H—
5/9 5/16 5/23
Figure A-78. Expansion of Figure A-77 for a solid-liquid ratio of 1:10 over more elutions
Duplicate runs.
-------
SERIES Rl PAINT WASTE
O.I N H2S04
MARCH 22
24
Figure A-79. Test Rl using procedure R to evaluate different
solid-liquid ratios over 5 elutions with paint
waste and 0.1N H,SCL. K.
209
-------
ro
o
K,ppm
3-r
2--
3/22
SERIES Rf PAINT WASTE
O.S N H2S04
SOLID-LIQUID RATIO 8 «IO
A COINCIDENT VALUES
I
'i 11 n 11 1111 M 111 itu i s i
4/1
-h
—i
4/20 4/25 5/2 5/9 5/16 5/23
Figure A-80. Expansion of Figure A-79 for a solid-liquid ratio of 1:10 over more elutions.
Duplicate runs.
-------
Mg,ppm
28-r
24--
20-
SERIES Rl PAINT WASTE
O.I N H2S04
MARCH 22
Figure A-81. Test Rl using procedure R to evaluate different
solid-liquid ratios over 5 elutions with paint
waste and 0.1N H^SO... Mg.
211
-------
ro
Mg9ppm
12 T
8- -
4--
SERIES Rl PAINT WASTE
o.i N H2so4
A COINCIDENT VALUES
SOLID-LIQUID RATIO I • 10
ittiimmiiWftiimttiitit
4-
3/22
4/1
4/20 4/25
5/2
5/9
5/16
5/23
Figure A-82. Expansion of Figure A-81 for a solid-liquid ratio of 1:10 over more elutions.
Duplicate runs.
-------
Fe, ppm
12.5-r
10.0- -
75--
SERIES R! PAINT WASTE
O.I N H2S04
MO
5.0--
2.5--
MARCH 22
24
Figure A-83. Test Rl using procedure R to evaluate different
solid-liquid ratios over 5 elutions with paint
waste and 0.1N H^SO,,. Fe.
213
-------
Fe, ppm
7.5-r
5.0--
2.5-
SERIES R! PAINT WASTE
O.i N H2S04
SOLID-LIQUID RATIO NO
A COINCIDENT VALUES
n n nniiiiiiii iiiin uniii i
3/22 4/1
+
f
4/20 4/25 5/2 5/9 5/16 5/23
Figure A-84. Expansion of Figure A-83 for a solid-liquid ratio of 1:10 over more elutions,
Duplicate runs.
-------
SERIES Rl PAINT WASTE
Zn, ppm
24 T
21-•
O.I N H2S04
3--
MARCH 22
Figure A-85. Test Rl using procedure R to evaluate different
solid-liquid ratios over 5 elutions with paint
waste and 0.1N H«SO,. Zn.
215
-------
l\3
*_J
CTt
Zn, ppm
12--
9- •
6--
o * *
3/22
4/1
SERIES Rl PAINT WASTE
0.1 N H2S04
SOLID-LIQUID RATIO I'10
A COINCIDENT VALUES
4/20 4/25 5/2
5/9
5/16
5/23
Figure A-86. Expansion of Figure A-85 for a solid-liquid ratio of 1:10 over more elutions.
Duplicate runs.
-------
SERIES Rl PAINT WASTE
COD.ppm
6000T
5000-
4000- -
3000- -
2000- •
1000- -
O.I N H2 S04
• I-100 •I'lO
• l«20 *l«7
A I'lO Xl'4
MARCH 22
Figure A-87. Test Rl using procedure R to evaluate different
solid-liquid ratios over 5 elutions with paint
waste and 0.1N H0SO.. COO.
217
-------
CO
COD, ppm
6000 T
5000--
4000
3000--
2000-
1000-
SERIES R! PAINT WASTE
O.I N H2S04
SOLID-LIQUID RATIO l« 10
COINCIDENT VALUES
3/22
4/1
4/20 4/25 5/2
5/9 5/16 5/23
Figure A-88. Expansion of Figure A-87 for a solid-liquid ratio of 1:10 over more elutions
Duplicate runs.
-------
K, ppm
7.5-r
6.0- •
4.5--
3.0- •
1.5-•
SERIES Rl PAINT WASTE
SYNTHETIC LEACHATE
MARCH 22
hlOO * I'10
1 = 20 v I-.7
MO x l«4
H H
24
28
Figure A-89. Test Rl using procedure R to evaluate different
solid-liquid ratios over 5 elutions with paint
waste and synthetic leachate. K.
219
-------
I\J
o
Kjppm
4.5
3.0 ••
I.5--
SERIES Rl PAINT WASTE
SYNTHETIC LEACHATE
SOLID-LIQUID RATIO MO
A COINCIDENT VALUES
1
• •
.* % A
A*
11 IIHIII im Minn uinnn i
I
A
3/22
4/1
4/20 4/25 5/2 5/9 5/16 5/23
Figure A-90. Expansion of Figure A-89 for a solid-liquid ratio of 1:10 over more elutions
Duplicate runs.
-------
Mg, ppm
28-r
24--
20--
16--
12--
8--
4--
SERIES RI PAINT WASTE
SYNTHETIC LEACHATE
• NQO + I'lO
a |«20 T h7
Al'IO x h-4
MARCH 22
Figure A-91.
Test Rl using procedure R to evaluate different
solid-liquid ratios over 5 elutions with paint
waste and synthetic leachate. Mg.
221
-------
ro
ro
fs>
Mg, ppm
12 T A
8--
SERIES Rl PAINT WASTE
SYNTHETIC LEACHATE
A COINCIDENT VALUES
SOLID- LIQUID RATIO I • 10
itttlItftttl
3/22
4/S
4/20 /25 5/2
5/9
5/16
5/23
Figure A-92. Expansion of Figure A-91 for a solid-liquid ratio of 1:10 over more elutions.
Duplicate runs.
-------
SERIES R2, PAINT WASTE
S/L RATIO'Oh5,AMO,Dl!20, SYN. LEACH. LIQUID
PH
6--
5--
4--
K CONCENTRATION, ppm
16 T
12-•
8--
REDOX,mV
100-r
75--
50--
E5--
Pb CONCENTRATION, ppm
2.0-r
2345
ELUTIONS
J 2 3 4 5
ELUTIONS
Figure A-93. Test R2 using procedure C to evaluate different
solid-liquid ratios over 5 elutions with paint
waste and synthetic leachate. pH, K, Redox, Pb.
*A11 points below detection limit are approximate.
223
-------
SERIES R2, PAINT WASTE 8 FLY ASH
S/L RATIO' Oh5, A MO, D 1=20, SYN. LEACHATE LIQUID
PAINT WASTE FLY ASH
Mq CONCENTRATION, ppm pH
60-r
8-r
Zn CONCENTRATION, ppm
IOOT
75--
50-
25--
4
K CONCENTRATION, ppm
300T
200- •
Cu CONCENTRATION, ppm
LOT
0.5-
234
ELUTIONS
234
ELUTIONS
Figure A-94.
Test R2 using procedure C to evaluate different
solid-liquid ratios over 5 elutions with paint
waste and fly ash using synthetic leachate.
Mg, Zn, pH, K, Cu.
224
-------
SERES R2, PAINT WASTE
S/L RATIO'OI'5,Al'iO,ai!20, O.I n H2S04 LIQUID
pH Fe CONCENTRATION, ppm
8-r
6--
4--
16 T
4--
REDOX, mV
400-r
300--
200-•
100-•
K CONCENTRATION,ppm
!6-p
2345
ELUTIONS
12345
ELUTIONS
Figure A-95.
Test R2 using procedure C to evaluate different
solid-liquid ratios over 5 elutions with paint
waste and 0.1N HLSO.. pH, Fe, Redox, K.
225
-------
SERIES VI
I • 5
TEST 2 • 6
SYMBOLS' 3 A 7
4*8
10-r
5 - •
evi
CO
i '.
\±
fc .5--
O
a
o
o
O.I
10 -r
6
DAYS
Figure A-96.
Test VI evaluating different contact procedures with fly
ash (EPA) and distilled water. (See text for procedure.)
Specific conductance an.d pH.
226
'/
-------
SERIES VI
35-r
30--
25--
TEST NO.
'05 2°-
<
u.
o. IS-
f 10-
w
__ TEST NO.
35-r 5 •
30O-r
300-r
DAYS
Figure A-97.
Test VI evaluating different contact procedures
with fly ash (EPA) and distilled water. K and COD.
227
-------
SERIES V2 PAPER MILL SLUDGE (PMS) 9
I0f
ro
IM
co
TEST NO.
8
3 DAYS 0
0
A
I
JO
Figure A-98. Test V2 evaluating different contact procedures with papermill sludge (N) and
distilled water. (See text for procedure.) pH.
-------
ro
INJ
CD
I.4T
.SERIES V2 PAPER MILL SLUDGE, (N),CONDUCTIVITY
1.4 T
10
Figure A-99. Test V2 evaluating different contact procedures with papermill sludge (N)
and distilled water. Specific conductance.
-------
SERIES V2 PAPER MILL SLUDGE (PMS) , N
Fa, ppm
O.ST
TEST NO.
0.4 - - 3 O——
0.3
0.2- •
O.I--
*DETECTION LIMIT*—*
0.5T
0.4
0.3 ••
0.2- •
•t-
, ppm
TEST NO.
7O—-__
-*^^j.
3r'
2 ••
I ••
F«/kg PMS
51 mg F« /kg PMS
H
3 DAYS
Figure A-100. Test V2 evaluating different contact procedures
with papermill sludge (N) and distilled water. Fe.
*A11 points below detection limit are approximate.
230
-------
SERIES V2 PAPER MILL SLUDGE (PMS) , N
K. ppm
TEST NO.
6-.
K.ppm
7T TEST NO.
5 +
6*
7O
6+ a a
5..
4..
3--
/kg PMS
mgK/ kg PMS
20--
10
3 DAYS
20--
10
Figure A-101. Test V2 evaluating different contact procedures
with paper-mill sludge (N) and distilled water. K.
231
-------
SERIES V2 PAPER MILL SLUDGE (PMS) . N
Co, ppm
Co, ppm
4
2-°
TEST NO.
6 A— .-
2©.
!0
/kg PMS
C«nfl Co/Kg PMS
2O—
10--
3 DAYS
Figure A-102. Test V2 evaluating different contact procedures
with paper-mill sludge (N) and distilled water.
Ca.
232
-------
SERIES V2 PAPER MILL SLUDGE (PMS).N
200T9'
ISO"
120"
80"
40--
TEST NO.
5*-
6*
320 -r
240- •
Mg/kg PMS
320V
240--
16(3--
80--
40
Mg/ kg PMS
DAYS
10
Figure A-103.
Test V2 evaluating different contact procedures
with paper-mill sludge (N) and distilled water. Mg.
233
-------
SERIES V2 PAPER MILL SLUDGE (PMS), N
COO, ppm
IOO°T TEST NO.
800- •
600
400-
200-'
I008?° °
800-•
600--
400-•
200- •
TEST NO.
5»
COD/kg PMS
4..
4
COD/kg PMS
ft
3 DAYS
10
Figure A-104. Test V2 evaluating different contact procedures
with papermm sludge (N) and distilled water. (COD)
234
-------
SERIES V3 PAINT WASTE, RW.
Zn, ppm
2.0T
1.0- •
0.
0.
Figure A-105. Test V3 evaluating different contact procedures
with paint waste and distilled water. (See text
for procedure.) Zn.
235
-------
SERIES V4 FLY ASH, (AA)
13
te-
ll-
IO
PH
13 T
12
II- •
10
TEST NO.
2
3 •
4
'5
6
7
8
-20
3 DAYS
-40
O -60
Q
LU
-SO
HOO
-20-
-4O
O -60
O
Ui
OS
-80
HOO
Figure A-106. Test V4 evaluating different contact procedures
with fly ash and distilled water. (See text for
procedure.) pH and Redox.
236
-------
CO
.8
.6
.3
.1
.08
.06
.03
SERIES V4 FLY ASH
(A A)
+
DAYS I
TEST
NO
7 |H
4
2 3
I 2
•3 4
.03
TESTf
NO. {
Figure A-107. Test V4 evaluating different contact procedures with fly ash and distilled
water. Specific conductance.
-------
K. ppm
I20T
100
80
60->
40
SERIES V4 FLY ASH (AA)
KBppro
80T
SO-
4O
3 DAYS I
TEST NO.
I auauvHna, K
2—— 6
3——— 7
4- a
too
ISO-
K/kfl FLY ASH
200
ISO"
too
DAYS I
IOO
K/kg FLY ASH
Table A-108. Test V4 evaluating different contact procedures
with fly ash and distilled water. K,
238
-------
SERIES V4 FLY ASH, (AA)
COO, ppm TEST NO. COO.ppm
I250T
1000-• . ^-^
750-
50O--
250-
3200-Cmg COD/kg FLY ASH 3200 T
COO/kg FCT ASH
2400-
1600
800"
240O-
I6OO-
800 ••
3 DAYS
Figure A-109.
Test V4 evaluating different contact procedures
with fly ash and distilled water. COD.
239
-------
pH
8-r
6--
SERIES V5 MUNICIPAL WASTE
TEST NO.
i •
2 •
3 A
4 •
REDOX, mV
60-r
H
3
DAYS
I
REDOX, mV
60
Test VS evaluating different contact procedures
with shredded municipal solid waste and distilled
water. (See text for procedure.) pH and Redox.
240
-------
SERIES V5 MUNICIPAL WASTE
4-r
X
O
O
LO--
jZO.4
O
o
o
o
0.1
4-
ro
0
X
S"
O
CO
o
X 1.0-
2 ;
*^Ui •
^__?* "
f~
r~
^
^^^ ^% fL m
H
0
m*J
O
z
o
0
n i
• TEST NO.
_ 5 •
6 •
7 A
. 8 » .,.
4 - ^
\
\
\
\
\
\
\
\
\
\
\
1^
s
X
X
X
DAYS
I
Figure A-111.
Test V5 evaluating different contact procedures
with shredded municipal solid waste and dis-
tilled water. Specific conductance.
241
-------
SERIES V5 MUNICIPAL WASTE
K, ppm
250-r
200- •
ISO- •
100
SO- •
K, ppm
250-r
20O- -
ISO--
100- •
50-- *
TEST NO.
5 •
6 •
7 A
8 «
2mg K / kg M.W.
600 T-
4SO--
30O--
ISO-
2mg K/ kg M.W.
600-r
45O--
300--
150--
0
DAYS
Figure A-112.
Test V5 evaluating different contact procedures
with shredded municipal solid waste and dis-
tilled water. K.
242
-------
SERIES V5 MUNICIPAL WASTE
2Q Fe« PP™ TEST NO.
3 •
6 •
7 A
«+ 8 *
12- •
8--
4- •
Zmg Fe/kg M.W.
50 T
37.3-
Fe/kgM.W.
25- •
12.5- •
Figure A-113. Test V5 evaluating different contact procedures
with shredded municipal solid waste and dis-
tilled water. Fe.
243
-------
SERIES V5
ppm
60
4S--
30-
IS- •
OL-*.
MUNICIPAL WASTE
Mg,ppm
75-r TEST ^
S •
6 m
7 A
60+ 8 V
43-
30--
15- •
0
2 mg Mg / kg M.W.
160-r
12,0--
80--
40--
0
Smg Mg/kg M.W.
I60-r
120--
80--
40 —
DAYS
Figure A-114. Test VS evaluating different contact procedures
with shredded municipal solid waste and dis-
tilled water.. Mg.
244
-------
SERIES V5 MUNICIPAL WASTE
Cu, ppm
1.0 T
0.8-•
0.6--
0.4--
0.2- •
.09
0
Cu,ppm TESTNOL
5 •
6 •
7 A
a •
0.8-•
0.6- -
0.4-•
0.2--
.09
0
2mg Cu/kg M.W.
3.0-r
2.25--
1.5-'
0.75- •
Zmg Cu/kg M.W.
>
I
2.25- -
1.5-•
0.75 - •
DAYS
Figure A-115. Test V5 evaluating different contact procedures
with shredded municipal solid waste and dis-
tilled water. Cu.
*Points below detection limit are approximate.
245
-------
SERIES V5 MUNICIPAL WASTE
Zn, ppm
12.;
10.0- •
7.5= -
s.o- -
2.5-•
Zn, ppm
12.5-r TEST N0-
6 *
7" ••"
8 *
IO.O+
75--
0*—*-
5.0- -
2.5--
0
2mg Zn/kg M.W.
32-r
24
16 •
0
Img Zn/kg M.W.
32T-
24--
16- •
8--
H
3 DAYS
Figure A-116.
Test V5 evaluating different contact procedures
with shredded municipal solid waste and dis-
tilled water. Zn.
246
-------
SERIES V5 MUNICIPAL WASTE
Ca, ppm
125 T
rao--
73--
5O--
25-.
TEST NO.
5 •
6 •
7 A
8 •
0«—4
2mg Co/kg MW.
300-r-
225--
ISO--
75--
Figure A-117.
2mg Co/kg M.W.
SOO-r
22S--
ISO--
75-.
DAYS
Test V5 evaluating different contact procedures
with shredded municipal solid waste and dis-
tilled water. Ca.
247
-------
SERIES V5 MUNICIPAL WASTE
COD, ppm
SOOO-r
2400- •
1800- -
1200-'
600->
COO, ppm
sooo-r
2400
raoo--
--I20O- • A
600—
01—t
TEST NO.
5 •
6 •
7 A
8 •
,4—
Zmg COD/ kg M.W.
Itooo-r
9 ooo--
6000=°
3 000 -•
2mg COD/kg M.W.
12000-r
9 ooo
€OOO- =
3000--
DAYS
I
Figure A-118.'"- Test VS evaluating different contact procedures
with shredded municipal solid waste and dis-
tilled water. COD.
248
-------
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO. 2.
EPA-600/2-79-109
4. TITLE AND SUBTITLE
BACKGROUND STUDY ON THE DEVELOPMENT OF A STANDARD ••
LEACHING TEST
7. AUTHOR(S)
Robert Ham, Marc A. Anderson, Rainer Stegmann,
Robert Stanforth
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Civil and Environmental Engineering Department
University of Wisconsin-Madison
Madison, Wisconsin 53706
12. SPONSORING AGENCY NAME AND ADDRESS
Industrial Environmental Research Lab. -Cincinnati, OH
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
3. RECIPIENT'S ACCESSION>NO.
5. REPORT DATE
May 1979
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
10. PROGRAM ELEMENT NO.
1BB610
11. CONTRACT/GRANT NO.
Grant No. R-804773
13. TYPE OF REPORT AND PERIOD COVERED
Final Report
14. SPONSORING AGENCY CODE
EPA/600/12
15. SUPPLEMENTARY NOTES
The principal objective of the research summarized in this report was to
develop a leaching test which could be used widely to assess the leaching charac-
teristics of industrial wastes. Detailed investigations were made regarding the
best general type of test, and the test variables and operating conditions which
must be standardized if the test is to be used by many laboratories and on differ-
ent wastes.
The recommended procedure is a batch or flask test, using distilled water
plus other leaching media according to the characteristics of the landfill(s)
of concern. One leaching medium simulates the leaching characteristics of
leachate derived from actively decomposing municipal refuse landfills, for
example. Test procedures were designed to provide information regarding the
materials likely to be leached,from a waste, an estimate of the maximum con-
centrations of these materials, an estimate of the amount of material likely to
be released per unit weight of waste, and an indication of the effect of co-
disposal of the waste in question with mixed municipal refuse or other specific
wastes.
17. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
Waste disposal
Earth fills
Industrial wastes
• '»."-* *> i ' - -.,
T
•i "
IS. DISTRIBUTION STATEMENT ' - - '
Release to Public " ''
b. IDENTIFIERS/OPEN ENDED TERMS
Solid waste management
Leach test
Leachate
19. SECURITY CLASS (This Report)
Unclassified
20. SECURITY CLASS (This page)
Unclassified
c. COSATI Field/Group
138
21. NO. OF PAGES
274
22. PRICE
EPA Form 2220'1 (9-73)
249
£l).S.GOV00MKHTrmilTni60RKE: 1979-657-060/1676 Region No. 5-11
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