United States
Environmental Protection
Agency
Municipal Environmental
Research Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-84-124 Sept. 1984
Project Summary
Comparison of Leachate
Characteristics from Selected
Municipal Solid Waste Test Cells
Richard J. Wigh
Leachate characteristics were com-
pared for samples taken from a
municipal solid waste test cell at Boone
County, Kentucky, and for samples
from other similar research projects.
Leachate concentrations and mass
removals from five test cells were
compared for at least three chemical
parameters. Weighted mean concentra-
tion histories were compared both
graphically and with a simple
mathematical description of the
concentration trend over time. Cell
performances were not identical, but
the normalized leachate data did
indicate repetitive trends and a range of
performance.
This Project Summary was developed
by EPA's Municipal Environmental
Research Laboratory, Cincinnati. OH,
to announce key findings of the
research project that is fully
documented in a separate report of the
same title (see Project Report entering
information at back).
Introduction
The Boone County Field Site (BCFS)
was established to investigate production
of leachate from municipal solid waste
test cells and other environmental effects
of landfills. Research was also conducted
to determine the effect of cell size on
leachate characteristics and history and
to compare the performance of identical
small-scale cells. Five municipal solid
waste test cells were constructed during
1971 and 1972. The research was
concluded and the site was closed in
September 1980.
One of the primary conclusions
reached in the Boone County study was
that most of the leachate constituent
concentration histories showed generally
similar trends. The concentration history
appeared to be based more on cumulative
leachate volume rather than on time.
Results also indicated that both identical
cells and different-sized cells demon-
strated a range of leachate behavior rather
than statistical similarity. The object of this
study was to compare results from
other municipal refuse test cells with
those of the BCFS to determine whether
leachate characteristics were similar
over a wider range of experimental con-
ditions.
Two of the BCFS cells and three
additional test cells were chosen for
comparison. One was a field-scale cell
constructed in Sonoma County,
California, during 1971. The two other
were from small-scale municipal refuse
cell research conducted at Georgia
Institute of Technology in Atlanta,
Georgia, by Frederick G. Pohland, and the
U.S. Environmental Protection Agency
(EPA) Center Hill Research facility in
Cincinnati, Ohio. Data for the selected
test cells are summarized in Table 1.
For these five cells, only chemical
oxygen demand (COD), chloride, and iron
were analyzed on a regular basis
throughout the entire project period for
all five studies. As a result, comparative
analysis of leachate composition had to
be limited in scope.
Findings
Typical weighted mean concentration
histories and mass removal plots are
shown in Figures 1 through 4. Data are
displayed as a function of cumulative
leachate volume rather than of time.
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Table 1. Summary of Test Cell Data
Avg. Annual
Leachate
Test Cell (L/kg dry refuse)
BCFS ttl
Sonoma Co Cell C
BCFS tt2B
Georgia Institute of
Technology Control Cell
Center Hill #4
057
1 91
0.58
2.15'
0.99
Refuse Mass
Dry Weight Max Refuse
(kg) Depth (m)
286,000
352.000
2.113
636'
1.855
256
2.62
2.56
3.28
2.4
Refuse Dry
Density
Ikg/m*)
429
460
314
186
290
equation increased with higher leachate
flow rate. Further modifications to the
equation were needed to make more
definitive performance comparisons.
The full report was submitted in
fulfillment of Purchase Order No.
C2652NAST by Regional Services
Corporation, Inc., under sponsorship of
the U.S. Environmental Protection
Agency.
"'Estimated Values
Leachate volume and mass removals
have been normalized by dividing by the
dry weight of refuse in the cell. Leachate
volume and mass removal from the
control cell at Georgia Institute of
Technology had to be estimated since
leachate volumes were not recorded.
Graphic comparisons of weighted
mean concentration histories and mass
removals for the two field-scale cells
indicated performance similarity for COD,
sodium, potassium, and ammonia-N.
Chloride concentrations and mass
removals had similar trends, but the
Sonoma data were very erratic during the
late portions of the study. Iron
concentrations showed little similarity.
Indications were that iron concentrations
were diluted by higher rates of leachate
flow, apparently because of a time-
dependent rate of iron availability from
the refuse mass. Calcium removals in the
Sonoma study were only 60% of those
in the Boone County field cell, perhaps
because of dilution from higher leachate
production. Ammonia-N removal differed
by only 15% at a cumulative leachate
volume of 4.5 L/kg of dry refuse.
Graphic comparisons of leachate char-
acteristics from the small-scale cells
were limited to the Boone County and
Center Hill studies because of lack of
leachate volume data from the work at
Georgia Institute of Technology.
Weighted mean concentrations for COD
for Boone County and Center Hill had
similar peaks at field capacity followed by
comparable downward trends. Mass
removals were almost identical over the
full range of the study. COD mass
removed from the field-scale cells was
only 60% of that from the two small cells.
Peak concentrations of chloride in the
two small cells were only slightly differ-
ent, but the concentrations in the Boone
County cell tended to be higher
throughout the study period, resulting in
a mass removal almost twice that
recorded at Center Hill. Iron showed very
little similarity in concentration or mass
removal, perhaps because of limited
solubility and subsequent dilution in the
higher flow Center Hill cell.
Cell performance was also compared
using a simple exponential equation
describing the leachate constituent con-
centration trends. The equation
correlated reasonably well with the
leachate history data over time (from the
point at which the cells achieved field
capacity to a cumulative leachate volume
of 4.5 L/kg of dry refuse). This correlation
was demonstrated by the fact that 13 of
the 20 curve fittings had correlation
coefficients of 0.95 or greater. Lower
peak concentrations at field capacity
were generally predicted for cells with
the highest leachate production rates.
The mass generation rate constant in the
o>
.§'
§
I
8
cj
c
<8
I
Sonoma, Cell C
BCFSttl
Figure 1.
234
Cumulative Leachate Volume. L/kg of Dry Refuse
COD concentration history.
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1
£
•s
1
o
I
8
•S
I
100
80
40
20
Sonoma, Cell C
BCFSH1
234
Cumulative Leachate Volume, L/kg of Dry Refuse
Figure 2. COD mass removal.
I
§
.
i
SO
40
30
2O
10
O—Georgia Control
A BCFSH2B
O Center Hill *4
2345
Cumulative Leachate Volume. L/kg of Dry Kef use
Figure 3. Small cell COD concentration history.
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o
I
§
O
1
(o
700
80
60
40
20
o- Georgia Control
A BCFSH2B
o Center Hill H4
Figure 4.
12345
Cumulative Leachate Volume, L/kg of Dry Refuse
Small cell COD mass removal.
Richard J. Wigh is with Regional Services Corporation, Inc., Columbus, IN 47203.
Norma M. Lewis is the EPA Project Officer (see below/.
The complete report, entitled "Comparison of Leachate Characteristics from
Selected Municipal Solid Waste Test Cells," (Order No. PB 84-220 276; Cost:
$ 10.00, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Municipal Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
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"ftGlUiM S LJoRARY
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U S GOVERNMENT PRINTING OFFICE, 1984 —759-015/7804
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