U.S. DEPARTMENT OF COMMERCE
National Technical Information Service
PB-254 550
TWELVE-MONTH EXTENSION SONOMA COUNTY SOLID WASTE
STABILIZATION STUDY
EMCON ASSOCIATES
PREPARED FOR
ENVIRONMENTAL PROTECTION AGENCY
1976
LIBRARY
J. S. ENVIRONMENTAL PROTECTION AGENCY
EWSOW. N. J. 0(817
I
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797084
TWELVE-MONTH EXTENSION
SONOMA COUNTY SOLID WASTE STABILIZATION STUDY
This final report (SW-120C) describes work performed for
the Federal solid waste Management programs under
contract no. 68-01-3122 and is reproduced as
received from the contractor
U.S. ENVIRONMENTAL PROTECTION AGENCY
1976
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NOTICE
THIS DOCUMENT HAS BEEN REPRODUCED FROM THE
BEST COPY PURNI8HED US BY THE SPONSORING
AGENCY. ALTHOUGH IT IS RECOGNIZED THAT CER-
TAIN PORTIONS ARE ILLEGIBLE, IT IS BEING RE-
LEASED IN THE INTEREST OF MAKING AVAILABLE
AS MUCH INFORMATION AS POSSIBLE.
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BIBLIOGRAPHIC DATA
SHEET
1. Report No.
12.
3. Recipient’s Accession No.
4. Title and Subtitle
Twelve-Month Extension Sonoma County Solid
Waste Stabilization Study
5. Report Date
1976
6.
7. Author(s)
EMCON Associates
8. PerForming Organizaika kept.
No.
9. Performing Organization Name and Address
EMCON Associates
1420 Koll Circle
San Jose, California 95112
10. l’roject/TaskfWork tlnu Nn.
11. Contract/Grant No.
68-01-3122
12. Sponsoring Organization Name and Address
U.S. Environmental Protection Agency
Office of Solid Waste Management Programs
Washington, D. C. 20460
13. Type of Report & Period
Covered
14.
15. Supplementary. Notes
16. Abstracts
This report documents the extension of a study originally performed
during a 3-year demonstration project sponsored by EPA and Sonoma County,
California. The purpose of the contracted extension is twofold:
(1) to investigate the stabilization of solid waste in a sanitary landfill
by analyzing leachate, gas, and settlement parameters, and (2) to
determine the effect on solid waste stabilization of applying, under
various operational modes, excess water, septic tank pumpings, and
recycled leachate in a sanitary landfill. This report discusses the
data produced through the end of the extension period. Tables and
figures following this report sumarize the data presented.
17. Key Words and Document Analysis. 17a. Descriptors
Landfill, Leachate, Septic Tank, Water
17b. Identifiers/Open -Ended Terms
Test Cell, Waste Management
lie. COSATI Field/Group
18. Availability Statement
PRICES SU IEC1 TO CHANGE
FORM NT13-35 (REV. 3-721
USCOMM-OC 14982-P72
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This report has been reviewe.d by the u.s. Environmental 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 mention of commercial products
constitute endorsement by the U.S. Government.
An environmental protection publication (SW-120C) in the solid waste
management series.
11
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TABLE OF CONTENTS
Section Page
I. INTRODUCTION
II. SUMMARY 2
III. CONCLUSIONS 4
IV. BACKGROUND TO STUDY 5
— Synopsis: Refuse Decomposition in a Typical Sanitary
Landft 11 Environment
- Refuse Decomposition and Its Potential Environmental
Impact
V. PROCEDURES AND RESULTS 8
- Leachate
- Gas
— Settlement
- Other
VI. DISCUSSION OF RESULTS 9
— Quantification of Landfill Stabilization by Analysis
of Leachate, Gas, and Settlement
— Cells A, B, and E
- Cells C and D
- Groundwater Quality
— Determination of the Effect of Varying Operational
Modes on Refuse Stabilization
— Application of Study FIndings to Operation of Full-
Scale Sanitary Landfills
- Leachate Treatment
- Gas Production
- Settlement
VII. IMPLEMENTATION OF RECIRCULATION AT FULL-SCALE LANDFILLS 19
VIII. REFERENCES 21
TABLE S
PLATES
FIGURES
iii.
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LIST OF TABLES
Table
Number Title
1 CondItioning, Operation and Purpose of Test Cells
2 Composition of Refuse - Various Studies
3 Parameters Measured During Study
1 Leachate Analysis - Cell A
5 Leachate Analysis - Cell B
6 Leachate Analysis - Cell C
7 Leachate Analysis - Cell D
8 Leachate Analysis - Cell E
9 Test Cell Gas Composition Data
10 Groundwater and Water Added, Cell C Quality Monitoring Data
11 Anticipated Fate of Leachate Components
LIST OF PLATES
Plate
Number Title
1 Test Cells Site Plan (as-built) — Plan View
2 Test Cells Site Plan (as-built) — Section, Cell D
iv
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LIST OF FIGURES
Figure
Number Title
1 Alkalinity of Leachate
2 BiochemIcal Oxygen Demand of Leachate
3 ChemIcal Oxygen Demand of Leachate
4 Chloride Concentration of Leachate
5 SpecIfic Conductance of Leachate
6 Iron Concentration of Leachate
7 Fecal Coliform Count In Leachate
8 Fecal Streptococci Count In Leachate
9 Lead Concentration of Leachate
10 - Mercury Concentration of Leachate
11 Nitrogen—Nitrate Concentration of Leachate
12 Nitrogen—Total Kjeldahl Concentration of Leachate
13 pH of Leachate
14 Sulfate Concentration of Leachate
15 Total Dissolved Solids Concentration of Leachate
16 Volatile Acids Concentration of Leachate
17 Zinc Concentration of Leachate
18 Average Cell Settlement
19 Methane Concentration of Cell Gas
20 Carbon Dioxide Concentration of Cell Gas
V.
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I. INTRODUCTION
The 12—month study for which this is the final report is, strictly
speaking,, an extension of the 3-year Sonoma County Solid Waste Stabiliza-
tiori S uçfy funded by the EPA under Grant G06-EC-0035l. The Third Annual
Reporttl) Issued for that project effectively discusses the data developed
during that study relative to the twofold purpose of the project as
stated in the introduction to that report. These were:
1. To investigate the stabilization of refuse in a sanitary land-
fill by analyzing leachate, gas, and settlement parameters.
2. To determine the effect on refuse stabilization of applying,
under various operational modes, excess water, septic tank
pumpings, and recycled leachate to a sanitary landfill.
The above are taken as the purposes of the extended study as well,
with one Important addition: the observations of the composite 1 1—year
study are applied through discussion toward improvement of operating
procedures at operational landfills. Indeed, the true value of any
Investigation such as this must lie in practical application to the
field it addresses.
For the original 3—year test program, five field-scale test cells
were constructed in late 1971 in Sonoma County, California, with general
features as presented in Plates 1 and 2. The cells are approximately
18 meters (60 feet) square in horizontal dimensions and 3 meters (10 feet)
In depth. The cells were constructed of clayey soils of relatively
impervious nature and were instrumented for data collection and for
leachate withdrawal and recycle where applicable. The Ca. 765 cubic
meters (1000 cubic yards) of refuse deposited in each cell was weighed,
subsampled for compositional analysis, placed, spread and compacted to a
density of Ca. 350 kilograms per cubic meter (1000 pounds per cubic
yard). Water and septic tank pumpings were added before final covering
to Cells B and E, respectively, in quantities sufficient to approximate
field capacity of the refuse. Subsequent to final covering, cells C
and 0 received daily applications of water and recirculated leachate,
respectively. Cell A, as the control cell, received no moisture beyond
that provided by rainfall. Table 1 summarizes the purposes of the cells
and the liquid conditioning applied to each.
Over the past le years, the leachate, gas, and settlement character-
istics of the five cells have been monitored to determine the effects of
the various conditioning procedures. This report covers the fourth year
of that period, extending the results reported In the Third Annual
Report referred to above.
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I I. SUMMARY
This study was designed to examine the effect of varying operational
regimes on the rate of degradation of refuse placed in simulated sanitary
landfill field test cells. The five test cells, each containing approx-
imately 765 cubic meters of municipal refuse at a density of Ca. 350
kilograms per cubic meter, were constructed In late 1971 and have been
operated continuously In the following modes: (1) inItial saturation of
the refuse with water; (2) daily, uni-directional through—flushing with
water; (3) daIly leachate reclrculatlon; (4) InitIal saturation of the
refuse with septic tank pumpings; (5) control.
Each of the cells was constructed to allow recovery of any leachate
or gas generated and for measurement of settlement. Groundwater monitor-
ing wells were established up and down gradient of the test cells to
allow detection of water quality changes attributable to the operation
of the test cells. The leachate from each of the cells has been sampled
during the last year at six-week intervals; gas and groundwater have
been monitored twice, and settlement three times, during the 12-month
study period.
The data generated during this study generally show a continuation
of trends established during the preceding 3—year study. The marked
difference in behavior between the group consisting of Cells A, B, and E
(without daily moisture addition) and that consisting of Cells C and D
(with daily moisture addition) continued to be evident, indicating a
greatly Increased rate of refuse degradation when subjected to continual
moisture addition.
The parameter levels measured in Cells A, B, and E indicate only
slight to moderate waste degradation. The leachate continues to be of
high strength characterized by low pH and high chemical oxygen demand,
volatile acids concentration, and total dissolved solids. The methane
content of gases from Cells B and E, water and septic tank pumping
additions respectively, has just recently begun to pick up, indicative
of establishment of methanogenic blodegradative mechanisms. Cell A
(control) gas continues to be essentially devoid of methane. Settlement
of Cells B and E does not significantly differ from that of the control
cell, all settling by approximately 7.5 percent of Initial refuse thick-
ness.
Cells C and D, daily water addition and leachate recycle respec-
tively, have shown extensive waste degrddation as evidenced by the
dramatic decline In leachate strength observed in the original study.
The present leachates are relatively low in chemical oxygen demand,
volatile acids, and total dissolved solids, and have a pH of near neutral.
Inorganic ions declined from original levels, but remain high compared
to municipal waste water. The gas evolved from these cells continues to
show very high methane levels, 65 to 70 percent by volume. The settle-
ment of both of these cells has greatly exceeded that of the other
group, with Cell D presently exhibiting a 20 percent decrease from
orIginal refuse thickness.
—2-
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Comparison of the extent of leachate attenuation provided by leachate
recirculation through refuse (Cell D) with that achieved in external
aerobic and anaerobic processes Indicated the processes to be of similar
effectiveness. All processes were effective in reducing organic loading
and total dissolved solids removal, but did little to diminish the
concentration of various Inorganic ions (e.g., Cl). The effluent from
each of these processes might need further treatment such as by ion
exchange or membrane filtration before discharge In certain situations.
Leachate r circulatIon appears to be promising as a technique for
both accelerating refuse decomposition and treating leachate. Sugges-
tions for application of recycle to limited portions of a full-scale
sanitary landfill are made in an effort to stimulate thought on the
subject.
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III. CONCLUSIONS
1. Cell A continues to exhibit leachate, gas, and settlement character-
istics consistent with behavior of a typical sanitary landfill. This
cell serves as a control cell (no additional moisture management),
against which the other cells are compared.
2. AdditIon of moisture to refuse at time of placement (Cell B) results
in some acceleration of the decomposition process. This is evidenced
by the Increased methanogenic activity presently occurring in this
cell relative to Cell A. Leachate and settlement parameters have not
demonstrated any significant variation from those of Cell A. LTttle
benefit or harm seems to result from moisture application on placement
other than accelerating the production of leachate and methane.
3. Continual flow—through of water (Cell C) results In a significant
increase in decomposition and also serves to flush soluble organic
and Inorganic constituents from the system. Vigorous methanogenic
activity and settlement continue. The rate of change of leachate
constituent concentration is approaching zero for most parameters.
The total mass of certain materials leached from Cell C waste is
consistent with that of other leach studies. Cell C mode of operation
is not recommended for application to full—scale landfills because
of the leachate volume produced. This cell may be representative
of response of a fill to high precipitation or surface water Inflow
and therefore may prove a useful model in these Instances.
1 . Leachate recycle (Cell D) is an effective method for reducing the
organic loading of leachate, less effective in TOS and Kjeldahl
nitrogen removal, and minimally effective In Inorganic Ion removal.
The process produces leachate that matches the organic strength of
municipal wastewater, but generally exceeds it in other constituents.
Generally recycle appears to be as effective as external aerobic or
anaerobic ponding with less likelihood of being adversely affected
by cold weather. Leachate recycle dramatically increases settlement
and therefore the achievement of physical stability of the fill.
5. Addition of septic tank pumpings (Cell E) has resulted in refuse
response similar to addition of moisture alone (Cell B). No slgnifl
cant differences have been noted between the two cells. Leachate
bacterial loading did not exceed that of other cells, so disposal
of septic tank pumplngs may be acceptable from a pathogen release
point of view. Viruses may be present, however, as test procedures
were not designed to detect these life forms.
— I.—
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IV. BACKGROUND TO STUDY
This study, like numerous others, has had as an implicit goal the
improvement of techniques for sanitary laridf filing of solid wastes. The
necessity for studies such as this stems directly from the sheer magnitude
of the solid waste disposal problem and the concomitant possibility for
large—scale detrimental effects on the environment and to pubflc safety.
The United States produces in excess of 115 millIon tons* of residential,
commercial, and institutional waste annual1 1 equivalent to a per capita
generation of 3 pounds* per day as of 1968. ti)
The composition of the above waste stream has been found to be
reasonably uniform throughout the United States, and has been character-
ized and reported by the National Center for Resource Recovery(2) as
shown on Table 2. The characteristics of the refuse utilized in this
study are also presented in Table 2 for comparison. The major portion
of the wastes generated (more than 90 percent) are disposed of to the
land, the most acceptable procedure being by sanitary landf filing.
Sanitary landflll lng has been defined as “an engineered method of
disposing of solid wastes on land by spreading them in thin layers,
compacting them to the smallest practical volume, and covering thçm with
soil each working day in a manner that protects the environment.”L3)
These practices are aimed at mitigating potential problems associated
with land disposal of solid wastes, such as breeding of vermin and
vectors, rapid consumption of site volume, production of odors, and
unfavorable visual impact. The landf filing aspects of greatest concern
and the most difficult to solve, however, are those associated with the
escape of the by—products of refuse decomposition from the site and the
effect these substances have on the land-water-air environment and on
public health. Since most problems associated with sanitary landfi1iing
are coupled in some manner to decomposition of the wastes placed within
a landfill, a knowledge of these degradative processes becomes essential
to effective operat.I on of this form of waste disposal. The mechanisms
of decomposition are of such fundamental importance to Interpretation of
study findings that a synopsis provides an effective foundation for data
presentation and discussion of findings.
Synopsis: Refuse Decomposition in a Typical Sanitary Landf ill Env ironment
The mechanisms of municipal waste decomposition have been described
in varying detail in numerous studies, including the precursor to this
one. Generally it can be said that a large portion of the solid wastes
placed in sanitary landfills undergo biologic and chemical transformation
to produce solid, liquid, and gaseous by-products. Substances such as
fats, proteins, and carbohydrates (e.g., cellulose, starches) are degraded
into progressively less complex compounds by multi-stage aerobic and
anaerobic microbial metabolic processes. Typical intermediate compounds
produced or liberated are organic acids (Including both volatile and
non-volatile fatty acids), inorganic ions, carbon dioxide (C0 2 ), water
*These figures do not Include agricultural, mining, or industrial waste. (2)
—5—
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(H 2 0), ammonia (NH 3 ), and others. Certain of these substances are
utilized in turn by other microorganisms which produce methane (CH4),
C0 2 , H 2 0, hydrogen sulfide (FI2S), and other simple compounds. Inorganic
ions are released during waste degradation, the solubility of many being
enhanced by the low pH found in landfills undergoing active degradation.
When most of the biodegradable material in the landfill has been consumed,
the refuse reaches a state of stabilization characterized by minimal
biological activity and a resultant low rate of production of gaseous
and soluble metabolic by-products.
Typically, refuse placed In a landfill will undergo an initial
relatively short phase (days to weeks) of aerobic (oxygen-requiring)
decomposition, followed by an extended period of anaerobic (oxygen-free)
degradation. The anaerobic processes are the more important because
rapid consumption of the molecular oxygen trapped on refuse placement
and lack of reintroduction mechanisms serve to limit the duration of
aerobiosis. Further discussion will therefore concentrate on anaerobic
degradation.
The early anaerobic biodegradation processes are dominated by
organisms employing acid fermentation type metabolism and yielding
volatile fatty acids, ethanol, a large number of inorganic ions (e.g.,
cr, soç 2 , Ca 2 , Mg 2 , Na 2 ) and a gas composed almost totally of CO 2 .
In this stage pH generally falls (ca. 5) because of volatile fatty acid
accumulation as well as the high partial pressure of C02. This stage is
followed by one in which bacteria utilizing methane fermentation meta-
bolism predominate. These methanogenic bacteria are strict anaerobes
(oxygen at any detectable level being extremely toxic) and in general
are slow—growing and have tight pH tolerances (6.6 to 7.4). The sub-
strates for methane formation by different species of methanogenic
bacteria have been given as H 2 + C02; formic, acetic, and butyric acids;
and ethanol and methanol. These substrates are made available from the
refuse material by the various precursor aerobic and anaerobic microbial
populations.
The activity and very existence of a microbial population depends
on a multitude of abiotic factors, especially moisture, gases present,
and pH, with a favorable range of values usually being definable for
each factor. The maximum and minimum values are physiological limits
beyond which the microbial population in unable to maintain itself or to
perform a vital function. For many factors an optimal level or range
an be established, in addition to upper and lower limits. The refuse
n Isture content, for example, has an important role in promoting stabili-
zation by decomposition. it is not possible at this point to quantita-
tively state what a minimum or optimum moisture content might be, but
gener ly speaking, the more moisture, the higher the rate of decomposi—
tion. ) The sensitivity of methanogenic bacteria to pH and 02 have
already been mentioned.
Certain data seem to contradict this concept of physiological
limits,, particularly in those instances where a cell or landfill simul-
taneously produces methane and leachate with a pH well below the minimum
necessary for survival of methanogenic bacteria. This can be explained
as follows. In a heterogeneous mixed—media system such as is found in
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• landfill, It is to be expected that many environmental conditions will
occur concurrently in different loci, resulting in the formation of
separate microenvironments wherein quite different types of organisms
may grow. Therefore, It is not surprising to find methane produced in a
landfill which appears from its leachate to have a pH of 5 (even though
methanogenic organisms cannot exist at pH 5), because pockets or regions
(mlcroenvironments) can exist in the landfill where conditions allow
these organisms to survive.
Refuse Decomposition and Its Potential Environmental Impact
As previously stated, the majority of the problems associated with
sanitary landfills result from degradation of the waste. Were the by-
products of waste decomposition to be restricted to the body of the
landfill, then most of these operational difficulties would be solved.
In many instances, however, groundwater or surface waters infiltrate the
refuse mass and form a solution containing many of the organic and
inorganic compounds formed by waste degradation. If this solution
leaves the refuse mass, it Is termed leachate. This leachate can seri-
ously impair the quality of any groundwater or surface water It contacts.
The gases produced (primarily CHI 1 and C0 2 ) can also migrate from the
fill. Methane is flammable in certain concentrations and thus can pose
a threat to public safety. Methane can cause an explosion If it accumu-
lates in an enclosed area and is Ignited. Carbon dioxide is readily
soluble In water, forming an acidic solution with a resultant increase
in the aggressive nature of the water and the quantity of minerals that
can be carried In solution. Another consequence of breakdown of the
waste In a sanitary landfill Is a reduction in bulk and the collapse of
voids in the refuse, causing settlement of the landfill surface which
affects the utility of the site for end usage.
The period during which a landfill undergoes active degradation
ranges from perhaps ten to hundreds of years, the time being dependent
primarily on the moisture content of the refuse. Thus, the problems
associated with any given landfill are likely to continue far beyond the
termination of refuse placement, and indeed may not appear for some time
after fill completion. Post—construction maintenance and care of a
completed landfill site to assure that it maintains its integrity and
does not become a source of pollution can therefore be a long-term
source of concern. If the rate of landfill degradation could be
accelerated so that the processes that normally might take 50 years
could be accomplished in 5, the period during which a completed landfill
must be cared for is reduced significantly. Also, an enhanced rate of
degradation means that associated effects such as settlement are also
accelerated, perhaps allowing the end usage of the site to be implemented
quickly and with fewer operational problems.
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V. PROCEDURES AND RESULTS
This section describes the experimental procedures utilized through-
out the study, and presents the results obtained.
Leechate : Samples of the leachate generated by each of the cells were
collected at six—week intervals during this study, utilizing procedures
described In Appendix C of Reference 1. The samples were analyzed for
the chemical and physical parameters presented in Table 3. Sample
analyses iere accomplished In general accordance with APHA Standard
Methods 5 ) with modifications where necessary. Further information
regarding analytical techniques for leachate can be found in Refer-
ences 6 and 7. The data developed during the present effort are pre-
sented In Tables 4 through 8 and graphically in Figures 1 through 17.
The figures also present 6-month means for data collected in the previous
3-year study to allow evaluation of current data in a historical perspec-
tive. Certain additional leachate components were quantified during the
original study, and the reader is referred to previous reports for
details.
Gas: Samples of decomposition gases were collected from probes located
within each cell and analyzed by gas-solid chromatography for percent
(by volume) of carbon dioxide (C0 2 ), nitrogen (N2), oxygen (02), and
methane (CH4). The Instrument was calibrated utilizing a known gas
mixture of CH4, N 2 , and C0 2 , accurate to better than one tenth of a
percent by volume. On occasion, gas samples were obtained with rela-
tively large concentrations of 02 and N 2 from probes sampling deep
within a cell. The 02 content Is assumed to be atmosphere derived and
due to leaks In the probe tubing allowing entry of air. The 02 and N 2
content were particularly suspect If present in a ratio of 1:4 (atmos-
phere ratio). The analyses showing the suspected air contamination were
corrected by removal of all 02 and of N 2 equal to 02 volume times 4, the
corrected values being presented with other gas analytical data in
Table 9. The corrected compositions are also presented graphically In
Figures 19 and 20.
Settlement : Surface settlement of each of the cells relative to fixed
bench marks has been monitored periodically since refuse placement.
Settlement is taken as the mean variation in elevation of 5 monitoring
plates permanently emplaced on each cell. The settlements exhibited by
the cells are shown In Figure 18 expressed as percent of the original
refuse thickness of 244 cm (8 feet). The cover was assumed to remain at
constant density and therefore to not contribute to settlement.
Other : Groundwater quality observation wells are installed at locations
shown In Plate 1. The water In these wells has been monitored twice
during the present study for electro-conductivity, pH, dissolved oxygen,
temperature, and water level. These data are summarized with values
obtained upon project commencement in Table 10. During various portions
of the previous 3—year study, additional data were collected on internal
cell temperatures, water quality in lysimeters located In the soil
beneath each cell, site precipitation, evaporation, runoff, and liquid
flow into and from the various cells. These data can be found in the
reports Issued under the original study.
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Vi. DISCUSSION OF RESULTS
The following discussion is organized to address the objectives of
the project, which were:
1. To investigate the stabilization of refuse in a sanitary
- landfill by analyzing leachate, gas, and settlement parameterS.
2. To determine the effect on refuse stabilization of applying,
under various operational modes, excess water, septic tank
pumpings, and recycled leachate to a sanitary landfill.
3. To apply the information gained in the composite 4-year study
toward improvement of operational procedures at full-size
sanitary landfills.
Also, conclusions and discussions presented in the Third Annual Report
submitted under GO6—EC—00351 generally are applicable to the data
developed during the present study, as trends and observations cited
therein have shown continued validity.
Quantification of Landfill Stabilization by Analysis of Leachate, Gas,
and Settlement
From the discussion of refuse decompositional mechanisms presented
In the Background section of this report, we can see that various
substances are characteristic of the differing types of microbial meta-
bolism occurring in a decomposing refuse fill. The processes are complex,
with multitudinous interactions, but for use here they can be generalized
to a sequential process wherein the heterogeneous microflora present In
a landfill are progressively varying in species composition as the
landfill environment changes. One group of bacteria degrade certain
compounds to simpler entities which are in turn utilized as substrates
by another group. This continues until the by—products produced are
incapable of supporting further biological growth. Many of the compounds
produced at varying points in this continuum of substance transformation
are either soluble in water or evolved as gases. it should be possible,
therefore, to deduce the relative location of a landfill along the path
of degradation by measuring the concentrations of these by-product
substances. This type of analysis was accomplished in some detail on a
cell—by—cell basis in the discussion section of the Third Annual Report
of the previous study, and will only be slightly extended here. Comments
are separated into two categories, those pertaining to Cells A, B,
and E, and those to Cells C and D. The differences of response between
the ABE group (without daily moisture addition) and the CD group (with
daily moisture addition) are considered to be of greater significance
than cell—to—cell variations within either group.
Cells A, B, andE : Cells A, B, and E continue to show levels of all
Teachate parameters indicative of slightly to moderately degraded waste
(see Tables 4-8 and Figures 1-17). The graphs of parametric concentra-
tions Indicate that leachate component levels may have reached peak mean
*This section also incluces a discussion of groundwater monitoring data.
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values (when corrected for seasonal fluctuations) between mid-1973 and
mid-1974, and may gradually be moving generally lower. The gas composi-
tion of Cells B and E Indicates that methanogenesis is becoming Increas-
ingly Important. Further evidence of the state of degradation in these
cells was derived from the composition of leachate by computation of
ithear correlation coefficients for various paired variables.
The leachates from Cells A, B, and E show correlation coefficients
in the .70 to .90 range for most paired variables examined. These cells
show a relatively high correlation of total dissolved solids (TDS) with
sulfate, chloride, and iron, and a low correlation of TDS with biochemical
oxygen demand (BOD), indicating Inorganic species to be an important
conponent of TDS residues. A low correlation of total Kjeldahl nitrogen
to volatile acids Indicates that a large portion of the nitrogen-
containing organics (e.g., proteins) have yet to be degraded to small
fragments (e.g., amino acids, volatile fatty acids).
It is likely that a significant portion of the large—scale, long—
term changes in level of many of the components in Cells A, B, and E
leachates is due to environmental influences affecting the dilution or
concentration of the leachates. Cell A seasonally exhibits an upward
movement of nearly all parameters as the leachate flow rate undergoes
its annual summer decrease. Cell A leachate parameters oF 6/27/75
relative to those of 2/19/75 indIcate a reasonably uniform 2.7 times
Increase across the board. This is most readily explained by evaporation
or other mechanisms causing an overall increase in leachate concentration
by approximately three times. Evaluation of correlations for Cells A,
B, and E, therefore, must also take into account the Influence of such
parallel trending.
Methane concentrations In the gas evolved by Cells B and E have
shown an increase from levels observed during the previous study, to 18
and 20 percent respectively, with that of Cell A continuing to remain
low at Ca. i percent. Cells B and E appear to be entering the methano-
genic phase of degradation and leaving the control Cell A as the only
fill to continue in non—methanogenic anaerobiosis.
Surface settlement continues as previously. Cells A, B, and E have
shown a mean settlement of 18.6 cm (0.61 feet) or 7.6 percent of the
original 244—cm (8—foot) refuse thickness. The settlement character-
istics are consistent with the general trend of data, indicating the
wastes of Cells A, B, and E to be undergoing decomposition at a rela-
tively slow rate. The concentration of fecal coliform in the leachate
for these cells continues to be low, while fecal streptococci have
demonstrated erratic fluctuations (213176).
Cells C and D : Both Cells C and D have succeeded to a large extent in
rapidly and effectively decomposing refuse with a concomitant production
of low—strength leachates. This Is graphically indicated by the trend
of most parameters In Figures 1 through 17. Cell D, which generally
shows the greatest degree of degradation and lowest-strength leachate,
has accomplished this without discharge of leachate from the system.
The time variation of the quality of leachate from Cell D corresponds
well with that derived from Percolation Bin No. 1 in Reference 8, an 18
month water application study. Cell C has produced and discharged in
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excess of 2 millIon liters (525,000+ gallons) of leachate, all of which
has either been disposed of by evaporation or injection Into an adjacent
landfill.
Reflective of the differing leachate character between Cells C
and D and Cells A, B, and E are the relative contributions of inorganic
versus organic species to the total dissolved solids (TDS) load. In
contrast to Cells A, B, and E, high correlatlonswere found in both
Cells C and D between total Kjeldahl nitrogen (TKN) and biochemical
oxygen demand (BOD), volatile acids (VA) and BOD, and TKN and VA,
indicating that these cells have degraded much of their organic matter
to short—chain organics, some of which are nitrogenous and may be amino
acids. That these components also make up the major portion of the TDS
load is demonstrated by high correlations of both TKN and VA to TDS.
That TDS is not highly influenced by other likely substances is shown by
the low correlation of TDSwith nitrate (NO 3 ), chloride (Cl), sulfate
(S04), and iron (Fe). The presence of nitrate, sulfate, and Iron In TDS
is highly dependent on the oxidation-reduction state of the leachate,
and will vary in response to changes In redox potential. The reduction
in SO 14 evident in Cells B, C, D, and E, Figure 11+, may be indicative of
enhanced reducing conditions. Also, correlations of both BOO and TKN to
alkalinity indicate the organic compounds that contribute to BOD may be
important proton acceptors.
Methane concentrations in the gas evolved by Cells C and D have
reached concentrations of 70 and 66 percent by volume respectively (see
Figure 19 and Table 9). Carbon dioxide concentrations are approximately
30 percent for both cells (Figure 20). Surface settlement for Cell C
continues as previously, but Cell D has exhibited a dramatic increase
(see Figure 18). Cell C shows a cumulative settlement of 30.8 cm (1.01
feet) or 12.6 percent of initial refuse thickness. Cell 0 has settled
cm (1.62 feet) or In excess of 20 percent. The large difference
between Cell C and Cell D is inferred to be Indicative of the greater
degree of decomposition that has presumably occurred In the latter. The
difference in settlement characteristics effectively rules out the mere
existence of high liquid flow rates as the predominant mechanism account-
ing for the enhanced biological activity of Cells C and D relative to A,
B, and E. Leachate recirculatlon apparently is more conducive to high
rate biodegradation of wastes than simple saturation of the wastes.
Fecal coliform counts continue to be low for both cells, while fecal
streptococci show apparently random, multiple order of magnitude fluc-
tuations of unknown cause.
The effectiveness of recirculation in reducing the mass of various
soluble constituents released to the environment can be assessed by
comparison of Cell C with Cell D. The mode of operation of Cell C
should allow an estimate to be made of the mass of a given component
that might ultimately be leached from refuse undergoing decomposition.
This hypothesis is based on the assumption that all leachable substances
exit the cell in solution via the collection system with Its associated
flow meter. The cell undergoes uni—directional flow, and it is assumed
to have a sufficient volume of water flushed through with uniform distri-
bution so as to allow solution of the majority of species capable of
leaving the system in this manner. Utilizing a mean concentration for
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each parameter over the project life, and a total leachate production of
approximately 2,000,000 liters, the cumulative output of Cell C for
several components has been the following:
COD - 24,000+ kg of 02 demand TKN - 600+ kg
Cl — 950+ kg S0j 4 - 350+ kg
Fe — 500+ kg TDS - 11,500+ kg
The effectiveness of Cell D mode of operations is shown by the fact
that if a volume of water equivalent to that which has passed through
Cell C were to be flushed through Cell D with the present leachate
concentrations, cumulative output for the above parameters would be as
follows:
COD - 750+ kg of 02 demand TKN - 1400+ kg
Cl — 1,000+ kg S0 1 - 30+ kg
Fe - 90+ kg TDS - 6,1400+ kg
Apparently BOD has undergone a reduction of 95 percent, chloride
not at all, Iron by 80 percent, TKN by 30 percent, S0i by 90 percent,
and TDS by 45 percent.
The performance of Cell C compares well with the conclusion in
Reference 8 that continuous leaching of 370,000 kilograms of refuse
(assuming 12115 m 3 300 kg/rn 3 (one acre—foot 500 lb/yd 3 )) would release
a minimum of 1365 kilograms (1.5 tons) of sodium plus potassium, 910 kilo-
grams (1.0 tons) of calcium plus magnesium, 830 kilograms (0.91 tons) of
chloride, 210 kilograms (0.23 tons) of sulfate and 35145 kilograms (3.9
tons) of bicarbonate. Summation of the above gives a predicted total
release of 6855 kilograms of material or 0.018 kilogram per kilogram
refuse. Assuming the data to represent total constituent analyses, as
was done in this study, and the above listed constituents to make up the
major portion of the total dissolved solids (TDS) content of leachate,
we find good correlation with the total TDS removed from Cell C. Cell C
has leached a total of 11,500 kilograms of TDS from the 11714,550 kilograms
of refuse placed in the cell, or 0.024 kilogram TDS/per kilogram refuse.
The mass of COD, C1 and TKN removed from Cell C when expressed as
mass constituent per mass dry refuse exceeded the measuremenls of the
content of these components in refuse utilized by Fungaroli.”9) The
results of the two studies are given below In kg component per kg dry
refuse.
Component Cell C Ref. 9
COD 9.0 x 10-2 11.3 x 101
Cl 3.5 x 10-3 9.7 x 10
TKN 2.2 x lO 1.3 x l03
The similarity of refuse composition utilized In the above two studies
is shown in Table 2.
Groundwater Quality : Monitoring of gro,.ridwater, Cells A and E subdralns,
and water added to Cell C shows valucs of water quality parameters
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consistent with those obtained during the origInal 3-year study. Table 10
shows the results of the two water quality analyses conducted dL’ring
this study, as well as the mean values obtained during 1972, the first
year of monitoring. The sole potentially significant development evident
in the data is the increase in the electrical conductivity and decrease
In pH measured in water taken from Well 2, downgradient of Cells A
and E, in the final sampling on September 30, 1975. These data, should
the trend continue, would suggest that ionic species have entered the
groundwater table from Cell A, Cell E, or both. If loss of leachate is
indeed occurring, it most probably results from direct connection of the
cell interior with the groundwater due to lack of adequate sealing of
one of the sand lenses encountered during cell constructton.(1) This
hypothesis might also be supported by the continued year-round production
of leachate by Cell A, albeit at varying seasonal rates, and an observed
progressive decrease in flow from the A and E groundwater subdrains,
both possibly a result of short-circuiting of groundwater flow through
the cell. It is unlikely that leachate is exiting the cell through the
clay barrier.
Determination of the Effect of Varying Operational Modes on Refuse
Stabilization
The principal thrust of this and the previous project was to determine
the effect, if any, of operating otherwise comparable field-scale test
landfills under differing modes Including: (1) one-time saturation of
the refuse with water, (2) daily uni—directional through—flushing with
water, (3) daily leachate recirculation, (4) one—time saturation of the
refuse with septic tank pumpings. The findings presented in the Third
Annual Report have continued validity at this time and are therefore
presented here in amended and augmented form. The bases for these
findings are contained in the discussion of that report and the reader
is referred to that source in addition to data and discussion presented
herein.
1. Control Cell A shows time dependence of leachate and gas composition
consistent with general behavior of typical sanitary landfills.
This cell provides a comparative standard for the four managed
cells.
2. The addition of moisture to refuse (to approximate field capacity)
In Cell B has accelerated decomposition processes to an observable
degree, as evidenced by its present enhanced methanogenic activity
relative to Cell A. Bringing the landfill materials to field
capacity immediately after placement accelerated the development of
leachate and presumably has enhanced biodegradation processes even
though not observed during the duration of this study in terms of
leachate quality. No significant increase In the rate of settling
of fill material relative to Cell A was observed.
3. Continual flow-through of water in Cell C has served to accelerate
the stabilization of refuse materials, flush out soluble materials,
and Increase the rate of settlement of fill material. The inorganic
solutes and organic solutes have been reduced dramatically. Pro-
duction of methane began early in this mode of operation and con—
tinues at a high rate.
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4. Reclrculatlon of leachate through the landfill material in Cell D
significantly enhanced the establishment of an active anaerobic
microbial population within the fill. The recirculation of leachate
has particularly Increased the rate of biological stabilization of
the organic fraction of the refuse, as evidenced by large reductions
in BOD and COD. Inorganic species have also shown significant
reductions In most cases. Leachate recirculatlon essentially uses
the landfill volume as a generally uncontrolled anaerobic digestor
for effective treatment of Its own leachate. The rate of surface
settlement has been greatly accelerated for the recycled leachate
mode of operation, with latest results (2/3/76) perhaps Indicating
that maximal settlement Is being approached (Figure 18).
5. SeedIng of refuse placed In Cell E with septic tank pumpings
without additional management accelerated acid fermentation pro-
c!esses, thereby facilitating establishment of anaerobic microbial
activity, but appears to have retarded development of vigorous
methanogenic organisms relative to Cell B. Leachate composition
and settlement show little significant variation from Cell A.
. pp1Icat1on of Study Findings to Operation of Full-Scale Sanitary Landfill! .
Sanitary landfills can continue to be a source of concern after
termination of refuse placement, with production of high-strength leachate,
migration of methane, and surface settlement presenting the greatest
difficulties. Because of the long time over which degradation occurs in
a normal landfill, mitigatory measures addressing these areas must often
be maintained for many years after site operations are completed. It is
conceivable that a landfill operator might be required to collect and
treat leachate, operate a gas migration control pumping system, or
postpone development of the site for the highest possible end use because
of projected continuing large—scale settlement. The necessity for
leachate and gas control and the concern with settlement could possibly
continue for decades. The response of Cell D to leachate recycle holds
promise ‘that the period during which those problems are significant
could be shortened, perhaps to less than 5 years after refuse placement.
The potential benefits are evident and worth pursuing If leachate recycling
can be applied, even limitedly, to a landfill.
Leachate Treatment : The constituents of landfill leachate can affect
the quality of receiving water in several ways. The organic and Inorganic
nutrient substances present can increase the biomass of the receiving
system by stimulating growth with a resulting acceleration of the rate
of eutrophication. The Inorganic salts add to the mineralization and
hardness of the system. Toxic substances may Inhibit the growth of
certain organisms and render the water unfit for various uses. Path99ens
might be carried from the refuse, posing a health hazard. One study’ )
concluded that escape of leachate from a sanitary landfill could “cause
the groundwater In the immediate vicinity . . . to become grossly polluted
and unfIt for domestic or irrigatlonal use.” Landfill leachate obviously
must not be allowed to enter usable water supplies without adequate
treatment.
Two basic approaches can be taken to mitigate pollution of ground
and surface waters by landfill leach tes. The first, taken In most
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cases, Involves treatment of the leachate as It is produced by the
landfill at a rate determined by site—specific infiltration and other
conditions. The variation of leachate strength with time in fills that
are not subject to moisture application indicates the period of produc-
tion of high—strength leachate can be quite lengthy. If treatment Is
provided by passive attenuation techniques (e.g., passage through soil),
thIs long time frame may not be important; the time frame will, however
be Increasingly important as required treatment procedures become more
complex, with concomitant Increases In management and maintenance
responsibilities and costs.
The important difference between a very old landfill that has
substantially degraded Tts waste to the maximum extent possible by
biological mechanisms and a young fill still undergoing active decom-
position is not the quantity of leachate produced per unit time, but the
quality of the leachate produced. If it Is assumed for purposes of
comparison that leachate from a biologically stabilized fill requires no
further treatment prior to discharge, then it can be seen that the more
rapidly a fill can be degraded, the shorter the time leachate treatment
would be required. This introduces the second approach that can be
taken in attenuating the leachate produced by a landfill, that of
recirculation to accelerate biostabilizatlon.
The effectiveness of leachate recirculation in mitigating leachate
pollutional capacity will vary according to the leachate constituents of
concern. The components examined by the current study can be divided
into three categories, according to whether they might be expected to
(1) degrade to innocuous end products or change toward levels found in
unpolluted waters, (2) be relatively immobilized within the refuse mass
by precipitation, adsorption, chelation, or other mechanisms, or (3) be
unaffected and therefore available for continued leaching, Irrespective
of the extent of refuse decomposition or changes In the biological/physical-
chemical conditions within the cell. This breakdown is presented in
Table 11, together with predicted trends.
In general, mineral components in varying forms are conserved and
unaffected by bacterial action, while organic compounds and chemical
Species such as sulfate (S04) are transformed to end products such as
methane (CH, 4 ), carbon dioxide (C0 2 ), water (H 2 0), and hydrogen sulfide
(H 2 s). The mobility of a large number of metals is broadly affected on
an inverse basis by leachate pH. Stabilization of the refuse usually
results in elevation of the leachate pH, approaching neutrality, which
tends to decrease the solubilization of many metallic ions, the transi-
tion elements zinc, cadmium, mercury and lead being the most highly
influenced. The halogens, alkali metals, and alkaline earths largely
remain available for leaching under a wide range of conditions. These
last, therefore, may represent the most likely components to be leached
from even a completely stabilized fill.
Table 12 compares Cell D leachate quality for certain parameters as
observed at project commencement with the lowest stable concentrations
achieved in that cell’s leachate. Also shown are typical ranges of ,
various parameters as typically encountered In municipal waste water.
Table 12 demonstrates that recirculation is effective to varying degrees
—1 5—
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In attenuating the strength of leachate constituents. It Is a highly
effective method for achieving decreased organic loading as evidenced by
the 98 to 99 percent removal of BOD, COD, and VA. BOD and COD of stabi-
lized leachate are approximately equivalent to moderate strength municipal
waste water. Recirculatlon was also reasonably effective In reducing
the total dissolved solids (80+ percent) and the total Kjeldahl nitrogen
content (70+ percent), although both are still approximately an order of
magnitude above that of municipal waste water. The Ionic strength of
the leachate was decreased but still probably exceeds that of waste
water by an order of magnitude (see chloride and TDS). Mao and Poh1and 15
found that artificial control of leachate pH at near neutral values
resulted in further acceleration of the stabilization beyond that provided
by recycle alone. These observations Indicate that the leachate from a
recirculated landfill is likely to be significantly decreased In strength
relative to an unrecirculated one (Cell A) but still, In most cases
other than organic loading, to be stronger than municipal waste water.
Additional treatment efforts may need to be taken, then, to further
attenuate the leachate from a recycled fill before It Is discharged.
Studies by Boy’e nd Ham,W) Ho et ai.,(l2) Cook and Foree,( 3
Thornton and Blanc,’ 14 ) and others indicate that, as regards leachate
treatment, other methods may be as effective as recirculation or may be
suitable adjuncts for furthering the treatment. Boyle and Ham examined
both aerobic and anaerobic treatment of leachate (10,000 mg/i COD) and
concluded that anaerobic methods were the most promising, yielding a BOD
reduction exceeding 90 percent at a 10-day retention time and temperature
between 23_300 C. Anaerobic processes deteriorated markedly under
conditions of reduced temperature (ca. 100 C), an Important consideration
f non-heated processes are considered in cold climates. Aerobic polish-
ing of the effluent leachate resulted in achievement of BOD values
commensurate with surface discharge (BOD = 40+ mg/l). Cook and Foree
utilized aerobic treatment and found leachate BOD (7000+ mg/l) to be
attenuated to 30 mg/i In 10 days. Effluent polishing by treatment with
activated carbon further reduced residual COD, organics, and color.
Sodium hypochlorite (bleach) was effective in color removal, but had
little effect on COD. Other physical-chemical treatments (alum, lime,
FeCl 3 ) were effective In total suspended solids removal and moderately
effective in color removal, but relatively Ineffective in COD removal.
Work by Ho et al. on the chemical treatment of leachates found lime
addition to be effective In removing multivalent cations (iron In particu-
lar) and color. None of the treatments tested appeared likely to have
any significant effect on COD or C1 concentrations. Boyle and Ham
Investigated the effect of addition of high-strength leachate in varying
proportions to domestic waste water on the operation of the extended
aeration treatment process utilized by many municipalities for waste
water treatment. Results indicate that this treatment process should be
able to handle ieachate with COD of approximately 10,000 mg/i at loadings
up to 5 percent by volume without seriously mpairlng effluent quality.
Higher concentrations were found to degrade treatment process operation
due to Increased loading of total solids, unfiltered BOD, and COD.
Results of this and other studIes, therefore, indicate landfill
recirculatlon to be as effective In Improving leachate quality as exter-
nally operated aerobic or w iaerobic methods. Recirculation Is less
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lIkcly to be iff’rtr’d by cold wentli’r and thus miy hc’ a superior method
u ik r I I o•. ituid I t I uu. . Add it Ii ii 1 i I inn I rn I I, r s t nlr n I iii (‘II 1 urn I ‘ r
either recirculation or external biude radatIon can iurthei reduce the
concentration of multivalent Ions (Fe ’’ 3 , Ca+ 2 , Mg+ 2 , etc.) and Improve
color. None of the chemical or physical processes attempted to date
have been effective in reducing the total mineralization of the leachate
to levels commensurate with those found in wastewater treatment plant
discharge. Inorganic Tons (Cl, SOi , Na+, K+, etc.) would be expected
to be attenuated by sorption mechanisms upon passage through appropriate
clayey soils, or external treatments such as ion exchange or membrane
filtration techniques might be employed.
Gas Production : Biodegradation of the susceptible organic constituents
of the waste deposited within a landfill results in the production of
various gases (methane, carbon dioxide, hydrogen, nitrogen, ammonia, and
hydrogen sulfide) in amounts dependent upon the particular microbiologic
processes occurring. From a theoretical standpoint, completed microbial
degradation of one pound of typical municipal refuse under optimal
conditions should yield approximately 3 cubic feet of CO 2 and 4 cubic
feet of methane. Typically, a landfill will undergo an initial, rela-
tively short phase of aerobic (oxygen—requiring) decomposition, followed
by an extended period of anaerobic (oxygen—free) degradation. The
methane—producing stage of anaerobic landfill biodegradation, which may
last for many years, is the most significant from an operational stand-
point, because of its duration and the potential impacts of its by-
products.
Operationally, landfill gas production can have several effects
worthy of consideration. Methane Is combustible in concentrations of
5 to 15 percent by volume in air, and explosive If ignited in a confined
space. Methane and other gases can migrate beyond fill limits, often
to significant distances, given appropriate permeable boundary soil
conditions and impeded cover venting. For these reasons, landfill
design must incorporate provisions for protection of on—site buildings
from methane accumulation and assure that off-site methane migration is
controlled to eliminate hazard development in adjacent structures. An
additional consideration is the fact that solution of carbon dioxide in
water can increase the acid nature of the water, increasing the solubill-
zatlon of many minerals and possibly resulting in increased water hard-
ness or metallic content.
The rate of gas production is dependent on a complex set of factors,
among the more important being moisture content and the amount of undegra-
ded organic material remaining in a landfill, a property likely to be
indicated by COD and VA content of the leachate produced. In situations
where moisture content is not limiting, gases will continue to be produced
throughout the period of biologic waste degradation. A stabilized
fill-—as indicated by low COD and VA-—would be expected to produce gases
at a low rate and thus to greatly minimize the potential for significant
gas migration. Landfills with significant quantities of organic material
remaining (high COD and VA) would be expected to produce gases at
higher rates. Gas migratory control, if required, is most likely to be
necessary during the period a fill is undergoing high rate decompositior.
(has high COD and VA). From Figures 3 and 16 this would be approximately
2 years for landfills with characterIstics like those of Cell D, ind
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apparently a very long time for those resembling Cells A, B, and E.
Recycle of leachate apparently would be very effective (pH adjustment
for maximal effect) in minimizing the period of time a gas control
system would need to be operated at a sanitary landfill.
Settlement : The rate of settlement generally follows the rate of blo
degradation, perhaps as represented by the rate of change in organic
loading as indicated by parameters such as COD, BOD, or VA. The more
rapidly a landfill achieves biological stabilization, the more rapidly
it will undergo that portion of total surface settlement attributable to
densificatton of the refuse resulting from its biodegradation. It is
estimated that settlement attributable to biologic transformation of the
waste represents the major portion of the total settlement. Figure 18
graphically illustrates the effectiveness of recirculation in enhancing
the rate of stabilization and therefore in shortening the time during
which significant settlement occurs.
The ultimate extent to which a Fill settles is largely depertdent
upon the degree of compaction of the waste that occurred upon placement,
with the rate of settlement being dependent upon moisture content. The
refuse placed in the test cells of this study achieved densities in
excess of 350 kg/cubic meter (1000 lb/yd 3 ) which is comparable to that
achieved in well operated sanitary landfills placing waste of similar
moisture content (20 to 30 percent wet weight). The present settlement
of Cell D (ca. 20 percent) may well be indicative of the ultimate settle-
ment that might be achieved in full-size landfills with similar refuse
characteristics. The response of control Cell A, however, indicates
that, without special management such as continual addition of moisture,
the time frame of achieving this settlement may be quite lengthy.
The significance of the extent of landfill settlement for construction
toward a final planned end use is evident. Where final site topography
is being created by refuse placement, allowance should be made by raising
the final fill surface above the ultimate elevation desired by an amount
commensurate with the projected settlement. The combination of long
time frame and magnitude of ultimate settlement will restrict the uses
to which a landfill can be placed or impose extensive considerations for
design solution. These considerations are well summarized in Chapter 8
of Reference 3.
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VII. IMI’LEMENTATION OF RtCIRC(JLA ION AT FULL-SCALF LANDFILLS
Establishment of leachate recirculation at an existing landfill
obviously requires that the fill have been constructed to contain and
collect any leachate generated. Fills constructed to these specifica-
ttons are likely to become Increasingly prevalent in those regions of
the country experiencing relatively high rainfall and vulnerable ground-
water conditions. Where collection of leachate is possible, reinjection
Into completed portions of a fill could be accomplished by constructing
a distribution field of trenches or vertical wells designed to inject
leachate within the upper level of the refuse fill.
Experience has shown, however, that leachate Injection systems can
often overload the percolation capacity of the adjacent refuse, thus
becoming Ineffectual. It Is therefore necessary to match the leachate
acceptance capacity of the system to the liquid application rate. This
could be done either by continuous application of leachate to the field
at a low rate or by sequentially applying the leachate to separate
portions of the field in turn at a high flow rate for a short period,
followed by a long recovery period. In most cases, it probably is not
practical to establish leachate reinjection over an entire landfill. If
mplemented, it Is most likely that only a portion of a landfill would
be developed for recirculatlon, the extensiveness of the system being
dictated by the volume of leachate generated by the entire site.
The selection of the portions of a fill to be committed to recycle
should integrate projected end use plans with the positive attributes of
fill response to recycle, such as rapid achievement of physical stability
through accelerated settlement and limitation of the period of high gas
production. Likely candidate areas for leachate application might be
the following:
1. Locations of anticipated structures with associated access
roadways and utility corridors.
2. Areas adjacent to off-site structures that might be adversely
affected by long-term gas migration. These affected areas
would need to be protected from gas during the period of
active degradation in the recycle area, but would most likely
have fewer long—term problems after stabilization had been
achieved and gas control terminated.
3. Areas adjacent to sanitary sewer lines for ease of disposal of
recirculated leachate or treated recirculated leachate.
Designating a limited portion of a landfill for recirculation
might also allow additional benefits to operators as regards the remainder
of the landfill. One possibility is that the remaining fill might
benefit from having a highly permeable cover whicri would allow entrance
of precipitation and free exit of gases. The flow of precipitation into
and through the refuse should greatly accelerate the stabilization of
the remainTng refuse in the landfill. The leachate generated could then
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be collected at the base of the fill and distributed to the rcclrculatior,
ar.’n for trrntment with sub equ’nt dicchnrqc. The (ja s evolved during
røfusci tIr o.npo Itior; would be nble to leave the fill through the permeable
surface, thus minimizing lateral migration.
Discharge of treated leachate from the recirculation area at a rate
approximating landfill production will require a progressive recircula-
tion system. To maximize leachate residence time in the fill and thus
achieve optimum leachate quality, leachate would be progressively collected
and reinjected through a sequence of subareas within the recirculation
area. After collection from the last subarea, the leachate would be
further treated as required to make it suitable for discharge. For such
a design to be Implemented, the area to be utilized for recirculation
must be designed for this function from the beginning, and probably
would be one of the first landfill areas to be completed.
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VIII. REFERENCES
I. LMCON Assoc.lates. Sonoma County solid waste stabilization study.
Environmental Protection Publication SW-65d.l. U.S. Environmental
Protection Agency, 1975. 283 p. (Distributed by National
Technical Information Services, Springfield, Va., as PB-239 778.)
2. National Center for Resource Recovery, Inc. Resource recovery from
municipal solid wastes/a state-of-the-art study. Lexington, Mass.,
Lexington Books, 1974. 182 p.
3. Brunner, D. R., and D. J. Keller. Sanitary landfill design and
operation. Environmental Protection Publication SW-65ts.
U. S. Environmental Protection Agency, 1972. 67 p. (Distributed
by National Technical Information Service, Springfield, Va.,
as PB-227 565.)
4. Alexander, M. Microbial ecology. New York, Wiley, 1971. 511 p.
5. American Public Health Association, American Water Works Association,
and Water Pollution Control Federation. Standard methods for
the examination of water and waste water. 13th ed. Washington,
Publication Office, American Public Health Association, 1971. 874 p.
6. Chian, E. S. K., and F. B. DeWalle. Compilation of methodology used
for measuring pollution parameters of sanitary landfill leachate.
Washington, U.S. Environmental Protection Agency, Oct. 1975.
176 p. (Distributed by National Technical Information Service,
Springfield, Va., as PB-248 102).
7. Mooij, H., R. D. Cameron, and E. C. McDonald. Procedures for the
analysis of landfill leachate; Proceedings of an international
seminar. Solid Waste Management Report EPS-4-EC-75-2. Ottawa,
Environmental Protection Service, Oct. 1975. 26 p.
8. Report on the investigation of leaching of a sanitary landfill.
Publication No. 10. Sacramento, California State Water Pollution
Control Board, 1954. 96 p.
9. Fungaroli, A. A. Pollution of subsurface water by sanitary landfills.
v. 1. Washington, U.S. Government Printing Office, 1971. (200 p.)
10. Metcalf & Eddy, Inc. Wastewater engineering: collection, treatment,
and disposal. New York, McGraw-Hill, 1972. 782 p. (McGraw-Hill
Series in Water Resources and Environmental Engineering)
11. Boyle, W. C., and R. K. Ham. Biological treatability of landfill
leachate. Journal Water Pollution Control Federation , 46(5):
860-872, May 1974.
21
-------
12. Ho, S., W. C. Boyle, and R. K. Ham. Chemical treatment of leachates
from sanitary landfills. Journal Water Pollution Control
Federation , 46(7): 1776-1791, July 1974.
13. Cook, E. N., and E. G. Foree. Aerobic biostabilization of sanitary
landfill leachate. Journal Water Pollution Control Federation ,
46(2):380-392, Feb. T974.
14. Thornton, R. J., and F. C. Blanc. Leachate treatment by coagulation
and precipitation. Journal of the Environmental Engineering
Division; Proceedings of the American Society of Civil Engineers .
99(EE4):535-544, Aug. 1973.
15. Pohland, F. G. (Georgia Institute of Technology, School of Civil
Engineering). Sanitary landfill stabilization with leachate
recycle and residual treatment; final report 1970-1974.
Washington, U.S. Environmental Protection Agency, Oct. 1975.
116 p. (Distributed by National Technical Information Service,
Springfield, Va., as PB-248 524.)
22
-------
-.
$CAII * III ?
T s •Ufl.flt S FIST
SSI . 1 vs. $
0 ’ . • ’
-.5- ,... 5—
$..S_.
• •S s £ S..$ l
• 5$ s S.H
— • .
— — — ...v..sa s its. S
PLATE I
-------
•Sss Detail on Figure 6
Lysimiter $
Sampling Terminal
Gas, Thermister)
g çvation
300
SECTION ‘8 S
CELL SITE
CELL P ’
PLAN AS BUILT)
COMPONENTS
Return
1,000 Gal.
Collection Tank
‘U
20
SCALE IN FEET
1,000 Get.
Distribution
N)
TEST
U
40
PIAT( 2
-------
TABLE 1
CONDITIONING, OPERATION AND PURPOSE OF TEST CELLS
CELL
DESIGNATION
INITIAL
OPERATiON
PURPOSE OF CELL
LIQUID
CONDITIONING
LIQUID
USED
DAILY
LIQUID
APPLICATION
gal/day
LIQUID
USED
A
None
None
None -
None
Control Cell
B
Field *
Capacity
Water
None
None
To determine the effect of high Initial
water content on refuse stabilization.
- C
None
None
700±
(200_t000)**
Water
To determine the effect of continuous
water through flow on leachate character.
.
D
None
None
1000±
(500_l000)**
Rec lrcu—
lated
Leachate
To determine the effect of continuous ieachate
recirculation on leachate character.
E
Field *
Capacity
Septic
Tank
Pumpings
None
None
To determine the effect of high Initial
moisture content, using septic tank pumpings,
on refuse stabilization.
* Field capacity Is the condition when a sufficient quantity of fluid has been added to the refuse
to cause a significant volume of leachate to be produced from the cell.
** Range of variation In daily application of fluid.
-------
TAIILE 2
COMPOSITION OF REFUSE - VARIOUS STUDIES
ITEM
Sonoma TestW
Cells — Calif.
(mean)
SOURCE OF REFUSE
National Center
for Resource
Recovery
Fungaroli 8
Food Waste
10.7
14.6
8.4
Garden Waste
10.4
12.5
6.9
Paper
40.6
42.7
53.3
Plastic, Rubber
4.6
3.5
1.6
TextIles
1.7
2.4
0.8
Wood
1.0
2.5
2.3
Metals
9.0
9.2
6.9
Glass, Ceramics
10.9
10.3
7.7
Ash, Dirt, Rock,
Fines
etc.
2.8
8.3
2.3
2.3
9.8
* Percent wet weight.
26
-------
lAflir I
PARAMETERS MEASUREU DURING S1UDY
Six Week
Alkalinity
8ioch mical Oxygen Demand (BOD)
Chemial Oxygen Demand (COD)
Chloride (C1)
Iron, Total (Fe)
Nitrogen, Total Kjeldahl (TKN)
Nitrogen, Nitrate (NO. )
pH
Specific Conductance
Temperature
Volatile Acids (VA)
GAS (semiannually)
by volume
Methane (CH,,)
Carbon Dioxide (C0 2 )
Nitrogen (N 2 )
Oxygen (02)
SETTLEMENT (three times)
% settlement
Twelve Week
Alkalinity
BOD
COD
Cl
Fe
Feca 1 Streptococci
Fecal Coliform
Lead (Pb)
Mercury (Hg)
N-TKN
N- NO
pH
Specific Conductance
Sulfate (SO , 1 )
Temperature
Total Dissolved Solids (TDS)
VA
Zinc (Zn)
OTHER (semiannual ly)
(Groundwatcr Wells
Water Added - Cell C
Cells A & E Subdrain )
Dissolved Oxygen (DO)
pH
Temperature
EC
Water Level (where appropriate)
LEAC HATE
27
-------
TABLE 4
LEACHATE ANALYSIS - Cell A
COHP ONENT( 1 )
SAMPLE COLLECTION DATE
2/19/75
4/9/75
5/22/75
6/27/75
8/14/75
9/30175
11/20/75
12/30/75
2/3/76
Alkalinity
B.O.D.
C.0.D.
Chloride
Fecal Coil. MPN/i0O ml
Fecal Strep. MPN/iO0 ml
I ron
2,316
12, 100
143,608
650
15
2,100
410
0.28
0.338
581
0.234
5.2
14,970
10,000
622
12.0
9,300
52
Mercury
Nitrogen
Nitrogen
pH(2)
Solids -
cecific
Sul fate
5,886
30,650
49,828
1 ,320
690
931
0.23
6.2
16,000
15.0
11,238
7,722
33,350
59,994
2,299
1,015
0.61
0.036
1 ,008
<0.008
4.6
33,340
21 ,000
1 ,146
16.0
22,920
97
— KJeIdah i
— Nitrate
T. 0. S.
Cond.( 2 )ji mhOS/Cn
9,405
42,150
69,172
2, 4149
3
9.3
740
1 ,309
1.0
5.5
13,000
26.0
26,640
15,939
42,850
71,315
3,017
1 ,537
0.7
0.005
1,182
1 .142
5.5
20,400
18,000
I , i6o
19.0
27,360
116
15,840
1i4 ,700
59,123
1 ,531
1 ,350
I ,061
0.42
5.2
18,000
14.0
22,800
8,910
23,000
33,368
2,970
3
<3
880
0.32
0.074
601
0.2
5.1
21,324
22,000
606
15,540
46
11 ,o88
42,000
44,770
2,258
1 ,303
853
0.9
5.7
15,000
15.0
20,520
14,91 ,9
38,600
27,550
4,148
3
11 ,000
1 ,282
0.63
0.033
989
<0.04
5.7
34,364
17,500
1,075
15.0
26,460
101
Temperature (2) (°C)
Volatfle Acids
Zinc
(1) Units in mg/i unless otherwise noted.
(2) Measured at time of sample collection.
-------
TABLE 5
LEACHATE ANALYSIS — Cell B
COMPONENT (1)
2/19/75
t f9/75
5/22/75
SAMPLE COLLECTION DATE
6/27175 8111e175
Alkalinity
8.O.D.
C.O.D.
Chloride
Fecal Coil. MPN/100 ml
Fecal Strep. MPN/lO0 ml
I ron
Lead
9/30/75
11/20/75 12/30/7! 2/3/7
0
3,860
18,000
53,728
1 ,250
9
2, 100
452
0.40
0.276
1,073
0
5.5
20,810
14,000
802
14.0
11,940
46
5,114
41 ,750
71 ,953
I ,565
930
1 , 146
0.16
5.4
16,000
13.0
12,138
her cu ry
Nitrogen
Nitrogen
pH (2)
Solids —
Spec I f I c
Sul fate
5,5144
21,250
46,879
2,788
580
0.39
0.008
1 , 108
<0.008
4.6
21,600
16,000
720
13.0
15,600
60
— Kjeidah l
— Nitrate
T.D.S.
Cond.( 2 hi mhos/cr
6,237
35,300
45,724
2,849
<3
43
345
1 ,21O
0.1
5.5
12,800
28.0
16,200
9,702
34,150
46,479
2,404
733
0.4
0.006
1,131
40.02
5.5
22,100
14,000
805
15.0
17, 100
42
9,603
31 ,750
58,726
1 ,723
626
I ,027
0.05
5.6
14,000
14.0
17,640
z
0
I-
Cb
0
‘I
C
C-
C
0
F.
9,207
27,000
41,516
4,008
<3
<3
505
0.43
0.036
989
<0.01
5.0
20,580
15,000
719
16,560
42
10,197
30,260
44,880
2,642
303
1,188
0.5
5.7
1 5,000
15.0
15,480
4
Temperature (2) (°C)
Volatfle Acids
Zinc
(1) Units In mg/I unless otherwise noted.
(2) Measured at time of sample collection.
-------
TABLE 6
LEACHATE ANALYSIS Cell C
COMPONENT( 1 )
SAMP
LE COLLEC
lION DAT
E
2/19/75
4/9/75
5/22/75
6/27/75
8/14/7
9/30/75
11120/75
12/30/75
/
2/3/76
Alkalinity
772
1,061
1,188
1,584
1,287
1,386
1,584
1,287
1,188
B.0.D.
2,725
4,900
2,900
3,050
2,400
1,710
1,450
1,680
1,430
C.0.D.
9,641
3,775
4,412
3,752
2,874
2,182
2,483
3,108
2,688
.
Chloride
100
7,592
114
121
546
60
514
49
849
Fecal Coil. MPN/100 ml
15
—
-
290
-
—
61
—
35
Fecal Strep. MPN/l00 ml
2,400
—
-
290
-
—
< 3
—
24,000
Iron
292
325
310
325
486
—
316
225
233
Lead
0.12
-
0.17
0.03
-
0.04
-
0.15
Mercury
Nitrogen — KJeldahl
0.312
146
-
130
0.542
130
120
0.007
72
-
66
0.093
78
-
103
0.033
77
1
Nitrogen - Nitrate
<0.01
0.06
0.08
0.5
(0.02
0.3
0.04
1.2
1.0
pH(2)
5.6
6.5
6.4
6.3
6.3
6.7
6.0
6.4
6.!
Solids - T.D.S.
3,640
—
2,884
2,268
-
2,328
—
1,828
S ecIf Ic Cond.( 2 )MmhOS/Cr
3,100
5,500
3,000
2,300
1,950
2,500
2,200
2,000
2,250
Sulfate
73
-
38
—
75
-
38
—
27
Temperature (2) (°C)
14.0
16.5
17.0
25.5
18.5
18.0
-
15.0
15.0
Volatile Acids
2,640
1,735
1,920
1,368
1,200
984
720
1,392
864
Zinc
1.79
—
24
—
51
-
12
—
0.5
(A)
(1) Units In mg/i unless otherwise noted.
(2) Measured at time of sample collection.
-------
TABLE 7
LEACFIATE ANALYSIS — Cell D
COMPONENT(l)
I SAMPLE COLLECTION DATE
2/19/75
4/9/75
5/22/75
6/27/75
8/14/75
9/30/75
Alkalinity
B.O.D.
C.0.D.
Chloride
Fecal Coil. MPN/lOO ml
Fecal Strep. MPN/100 ml
I ron
I
2,316
202
1,899
2,000
930
24,000
72
0.16
1.236
214
cO.O1
6.6
3,350
4,700
240
13.0
120
0.34
2,798
190
394
244
110
210
0.4
6.3
12,000
15.5
36
Mercury
NI trocen
N trogen
pH(2)
Solids —
Spec I f Ic
Sul fate
2,574
123
539
506
100
0.10
0.006
217
0.02
6.2
3,216
6,000
16.5
16.0
312
0.17
— Kje ldah l
- Nitrate
T.D.S.
Cond.( 2 )M nthos, n
2,475
385
625
514
120
1 ,200
47
219
0.4
6.6
5,500
24.0
96
2,574
1 52
525
539
100
0.06
0.011
246
0.5
6.8
3,252
‘# ,900
69
19.5
86
0.13
2,871
111
460
305
55
212
0.63
6.9
5,000
19.0
96
2,772
104
512
555
20
23
51
0.22
0.020
205
0.02
6.2
3,264
8,ooo
82
24
0.93
2,772
145
429
536
50
229
0.14
7.0
6,000
16.5
216
Temperature (2)
Volatile Acids
Zinc
(°c)
2,871
143
685
770
“3
24,000
50
0.12
0.028
256
1.2
6.7
3,244
6,000
27
16.0
168
1.0
(1) Units in mg/i unless otherwise noted.
(2) Measured at time of sample collection.
-------
TABLE 8
LEACHATE ANALYSIS - Cell E
COMPONENT( 1 )
SAMPLE COLLECTION DATE
2/19/75
4/9/75
5/22/75
-
6/27/75
81)4/75
9/30/75
-.
1/20/75
12/30/75
.
2/3/76
6,080
23,000
5,983
38,250
5,742
19,000
7,326
30,150
11,385
38,100
11,583
33,700
10,890
32,700
10,890
28,000
11,583
37,750
MPN/100 ml
MPN/iO0 ml
86,480
1,600
<3
750
692
36,120
2,006
-
690
50,249
2,690
770
50,648
4,648
(3
<3
514
52,156
3,253
1,083
‘.4,838
1,960
-
53,156
3,961
< 3
< 3
840
45,510
1, 9
865
40,992
3,998 I
‘- 3
1,100
1,000
0.66
-
0.52
—
0.60
0.41
0.70
1.134
-
0.011
0.004
0.069
0.043
Kjeidahi
Nitrate
T.D.S.
Cond.( 2 )iimhOS,b
1,432
0.403
5.3
29,070
17,000
1,207
0.26
5.4
18,000
923
0.3
4.6
25,688
17,500
1,235
0.3
5.6
12,000
1,182
0.12
5.4
27,532
16,000
1,106
<0.03
5.4
16,500
1,064
<0.01
5.0
27,012
19,000
1,191.
1.6
5.6
—
16,000
1,111
0.6
5.7
25,652
16,800
(2) (°C)
1,271
10.0
-
15.0
849
16.0
—
29.0
1,093
17.5 .
—
14.0
460
-
-
15.0
759
15.0
Acids
18,600
74
12,378
—
18,360
74
18,480
-
20,160
91
12,900
—
19,620
69
16,992
—
18,300
64
(1,
(1) Units in mg/i unless otherwise ncted.
(2hieasured at thne of sample collection.
-------
TABLE 9
TEST CELL GAS COMPOSITION DATA
Sample_Source
Gas Component
2/19/75
11/20/75
Uncorrected
Corrected
Uncorrected
Corrected*
Call
A
CH 4
-
0.6
1.1
1.2
1.3
CO 2
28.2
50.3
76.9
80.8
N 2
66.6
48.6
21.1
17.9
02
4.5
0.0
0.8
0.0
Cell
B
CH 4
2.5
3.0
13.3
18.1
CO 2
41.1
50.1
37,5
51.2
N 2
54.5
46.9
45.5
30.7
02
1.9
0.0
3.7
0.0
Cell
C
CH 4
61.7
70.7
70.2
70.2
CO 2
24.3
27.9
29.6
29.6
N 2
11.4
1.4
0.2
0.2
02
2.5
0.0
0.0
0.0
Cell
D
CH 4
55.8
61.5
66.8
66.8
CO 2
35.0
38.5
30.3
30.3
N 2
7.0
0.0
2.9
2.9
02
2.2
0.0
0.0
0.0
Cell
E
CH 4
7.0
32.7
20.5
20.5
CO 2
14.4
67.3
68.0
68.0
N 2
57.1
0.0
11.5
11.5
02
21.5
0.0
0.0
0.0
* See text for explanation
33
-------
TABLE 10
GROUNDWATER AND WATER ADDED, CELL C
QUALITY MONITORING DATA
pH Spec.
DISSO1.a
Temp.
Depth
to
Source Date Cond.
(phoslcm)
Oxygen
(mg/i)
(°C)
Water
(m)
Well 1 InitlaiC 73 5.5 18.0 1.7
4/9/75 7.2 1.00 74 14.0 0.5
9/30175 7.2 450 12 b 19.0 1.5
Well 2 Initia lC 7.2 370 5.7 18.0 2.3
4/9/75 7.2 130 10.0 14.0 0.7
9/30/75 6.8 1200 28 b 20.0 1.9
Well 3 Inltia lC 7.2 320 6.0 18.0 2.2
4/9/75 7.3 65 6.8 14.0 1.2
9/30/75 7.4 300 2 • 7 b 19.0 1.6
Well 4 InltialC 6.7 310 4.9 18.0 2.2
4/9/75 6.8 75 7.8 16.0 4.1
9/30175 7.8 470 34 b 19.0 5.5
Water Added Initia lC 7.8 800 8.0 18.5
Cell C 4/9/75 8.2 60 10.2 13.5
9/30175 7.4 280 66 b 15.0
Cells A&E Initia lC 5.8 400 5.5 i8.o
Subdrain 4/9/75 7.5 220 7.0 16.0
9/30/75 No flow - - -
a. Method of sampling results in extensive sample aeration and would
serve to invalidate D.O. measurements.
b. Questionable data - probable instrument malfunction.
c. Mean of 1972 data.
34
-------
TABLE 11
ANTICIPATED FATE OF LEACHATE COMPONENTS
A. Components that will degrade or properties that will change
Parameter
Alkalinity
Biochemical Oxygen Demand (BOD)
Chemical Oxygen Demand (COD)
N-Nitrate (NO 3 )
N-Total KJeldahl (TKN)
pH
Total Dissolved Solids (TDS)
Specific Conductivity
Sulfate (SOb)
Volatile Acids (VA)
B. Immobilized compounds
Iron (Fe)
Lead (Pb)
Zinc (Zn)
Predicted Trend
Decrease
Decrease - organics to CD 2 , CH 4
Decrease - organics to CD 2 , CH 14
Decrease - nitrogenous compounds to Nil 3
Decrease - nitrogenous compounds to NH 3
Increase toward neutrality
Decrease
Decrease
Decrease - ultimately to H 2 S
Decrease - organics to CD 2 , CH 1
Decrease (function of pH increase)
Decrease Is
Decrease
C. Compounds with enhanced or unaffected mobility
Chloride (Cl)
Little change
35
-------
TABLE 12
CELL D LEACHATE
ATTENUATION AND RELATIONSHIP TO OTHER WASTE WATER
I
Parameter
CELL D
Current
Cell A*
Current
Leachate
Domestic*
Waste Water
9
Initial*
Leachate
Leachate
Change
Alkalinity
5,000
2,500
50
12,000
50-200
BOD
25,000
150
99+
40,000
100-300
COD
37,000
500
98+
50,000
250-1000
C1
1,000
500
50
2,500
30-100
Fecal Coil. MPN/iOO ml
Fecal Strep. MPN/100 ml
0
3.7x10 6
100
500
--
99+
<3
<3
-
--
Fe, Total
180
75
50+
1,000
--
Nitrogen, Total Kjeldahl
800
220
70+
1,000
20-85
pH
5.0
6.5
——
5.2
—-
TDS
Specific Cond. p mhos/cm
16,500
11,000
3,200
6,000
80+
40+
20,000
20,000
250-850
--
Volatile Acids
10,000
100
99
20,000
--
Zn
50
<1
98+
75
--
* Units in mg/i unless otherwise noted.
36
-------
10,000—
8,000—
6,000—
4,000-
-J
4
2,000—
TIME
ALKALINITY OF LEACHATE I FIGURE
TIME
BIOCHEMICAL OXYGEN DEMAND OF LEACHATE
0•
.4 .
‘ . 4
--
/
- — —
1972
I I
1973
I I I
1974
F’M’ MI.J’A’S’Q’N 1 D ,jI
1975
E
z
4
0
U i
C,
x
0
-J
4
C)
U i
x
C,
0
50,000
40,000
30 00
20,000
10.000
S.
0
1972
1973
1974
j7
I FIGURE
-------
E
a.
z
a
z
L i i
0
0
-J
C-,
Ii i
z
C-,
3,500—
3,000—
2,500—
2,000—
E
1,500—
0
t,000-
500-
I FIGURE
198
j 3 .$ 9 8
I I ‘ I J’F’M’M’JJJ’A’$ 1 O’N bfJ’
1972 1973 1974 1975 I
TIME
CHLORIDE CONCENTRATION OF LEACHATE FIGURE
/
/
/
/
/
I.
/
/
t
I ’
I
1972
‘973
1974
TIME
CHEMICAL OXYGEN DEMAND OF LEACHATE
(975
, -
•1
I
/
\
—
4
-------
J’F’M’A’M’JIJ’ASbO’N’O J.
$975
SPECIFIC
CONDUCTANCE OF LEACHATE
I FIGURE 5
2,000—
“$00-
1,600—
1,400-
zz 1,200-
E
i 1,000-
z
0
800-
600—
400—
200—
a
1972
1973
‘974
TIME
IRON CONCENTRATION OF LEACHATE
1 JFMAMJ J’A’S’Q’N’DJ i’
$975
F
25,000—
20,000-
15,000—
U
0
I-
w
0
z
4
0
C.,
0
U-
3 5,000—
U i
a-
U,
10,000-
1
/ I..
I
‘ I I I I l I
$972 1973 1974
TIME
.
:
— I.... . — _— ——L_ _
— —
I FIGURE
-------
r
S
C
0
z
a.
0
-J
0
C.)
-J
4
0
I J
I FECAL COLIFORM COUNT IN LEACHATE
1973
FECAL STREPTO(L 3CCI
COUNT IN LEAC.IAE
101.
NOTE: Curves plotted to Indicate trends.
See Tables 4—8 for inc iduol lest results.
10
1972
1974
TIME
1975
toe
to?
FIGURE
E
0
0
z
a-
C -)
C)
0
0
0
I—
0.
U I
I—
C l )
-J
4
0
IL l
I L
NOTE: Curves plotted to Indicate trends.
See Tables 4-8 for IndIvidual test results.
102
10
N
S.’
1974
TIME
______ . . . -1
a
-------
2.
LEAD CONCENTRATION
I I I I
1972 1973 1974
TIME
MERCURY CONCENTRATION OF LEACHATE
JFMAM’.JIJA’SO ND J
1975
1.5
0
w
-J
I.
1973
TIME
OF LEACHATE
‘—
I FIGURE
9
E
0
w
0.1-
0.0I—
0.00I-
0.000I’
S..
/
S . .,
FIGURE 10
-------
5-
w
I-
z
Li
0
______NITROGEN (NITRATE) CONCENTRATION OF LEACHATEI FIGURE
2 000-
(,800-
, I 6OO-
E
,4OO-
-J
1,200-
-J
Li
‘ 1,000-
-J
800—
I—
z 600—
I d
C l ,
0
Q 400-
I—
z
200—
1972 I
‘973
‘974
TIME
1 JFMA t MJIJAIS&QIN?ojJI
1972
‘973
1974
TiME
‘975
/
I
I.
/
/
/
\ /
1
- ‘S. _ — .— I
NITROGEN (TOTAL KJELDAI-IL) CONCENTRATION OF LEACHATEIHGURE
12
-------
7.0-
/
‘ I ‘ I I
I I
.J’F’I ’A’f i’JIJ’A’S’O’N’D J
1972 1973
1974
1975
•
TIME
pH OF LEACHATE
I FIGURE 13
SULPHATE
TIME -
CONCENTRATION OF LEACHATE
U) 6.0-
I-
z
x
a.
I’
I’
I
5.0-
A A..
/
/
/
E
w
I
a.
-j
U)
1975
FIGURE 14
-------
40,000—
2,OOo-
E
U)
0
24,000-
0
U)
0
IJJ
>
-J
0
U)
U)
0 —
-J
I-
0
I.-
16,000—
8,000—
1 I J’F’MAJM’JIJ 1 A S’O 1 N 1 D JI
1974 1975
TIME
TOTAL DISSOLVED SOLIDS CONCENTRATION OF LEACHAT.E 1 iGURE
VOLATILE ACIDS CONCENTRATION OF LEACHATE FIGURE 16
p
p
_ - .-.
• 1 •..
‘I
I’
I’
— — % _•Il
I I -
1972 1973
IS
• • • •
C ,
E
U)
0
l i i
-J
-J
0
>
TIME
-------
I 6
U
z
N
TIME
ZINC CONCENTRATION OF
LE AC H AT E
I FIó tii i
17
• I-
• z
w
I&I
-I
I-
.1-
w
U)
15
S ...
‘. 5.
S ..
.5
. 5.
* Average value of 5 8ettlement plates per cell.
Settlement expressed as percent of original
refuse thickness of 244 cm.(8 feet).
S ..
1972
N.
1973
1974
TIME
AVERAGE CELL SETTLEMENT*
FIGURE 18
-------
1972
METHANE CONCENTRATION OF CELL GAS I FIGURE
I 1973
I 1974
riME
/
/
/
0
E
0
>
.0
U i
z
I—
Ui
0
E
.0
Ui
a
0
a
z
0
I D
0
1973
TIMES.
1974
1975
Ioo —1
80-
19
60-
40-
V
V
20-
1972
1 .1FMAM’JIJASON0 1 4’
l9
CARBON DIOXIDE CONCENTRAT1 N OF CELL GAS I FIGURE
20
ucy138
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