-------
volume recovered ranged from 215
ml to 236 ml. Thus, since the soil
was not at field capacity, a portion
ranging from 14 ml to 35 m] of the
applied liquid remained in the soil.
Data Analysis and Interpretation
The data produced from this
experimental programme consisted
of concentrations of various
contaminants remaining in the liquids
after contact in each of the 10
reactors. The analyses included
chloride, sodium, potassium, calcium,
magnesium, total iron, manganese,
copper, zinc, COD, ammonia, and
organic nitrogen. These concentra-
tions decreased with contact in
successive reactors due to the
combined influence of dilution and
other attenuating processes. It
was intended that the data be used
to prepare contaminant removal
isotherms for use in constructing
breakthrough curves to simulate
column behaviour.
Table 1 showed that the leachatc
used in this study consists of a
complex combination of chemical
components. This is to be expected
for all leachates obtained from
municipal refuse. It can be assumed,
therefore, that the attenuation
of a specific component will be
influenced by the presences of
others. This will be particularly
true where sorption processes are
involved. Thus, some components
will experience retarded removal
because of selectivity phenomenon.
The prediction of this influence
in a field situation would be an
arduous task. Yet some account
must be taken of it. The approach
used in this study attempts to
accomplish this accounting.
Removal isotherms could have
been prepared by creating serial
dilutions of the raw Icachate and
contacting these in the dispersed
soil reactors. This would have
generated data on contaminant removal
as a function of concentration but
would not have taken into account
the existence of retarded removal
of some ions. Consequently, the
technique of passing leachate from
one reactor to the next was
developed. In this way, the
influence of retarded removal could
be felt.
Removal isotherms were prepared
for the ammonia nitrogen and
potassium ion. These are shown
in Figures 7 and 8.
_l I0r
o
Cf>
K
o
UJ
6 01
s
X
ooi L
i
10 100
EQUILIBRIUM CONCENTRATION -
IOCC
Figure 7. Removal isotherm for
ammonia nitrogen.
•0001
10 IOO
EQUILIBRIUM CONCENTRATION - mg/M
Lj
IOOC
Figure 8. Removal isotherm for
potassium.
64
-------
The concentration, C, on the abscissa
are those measured in the liquids
collected from the reactors. These
were taken as equilibrium
concentrations for the removal
processes. However, the mass of
the particular component removed
was calculated as the mass added
to the reactor minus [the mass
discharged from the reactor plus
(the mass remaining in the soil
liquid minus the mass in the soil
liquid prior to contact)]. The
mass removed was divided by the
dry weight of soil within the
reactor, expressed as mass
removed/1000 g dry soil (X/M) and
plotted as the ordinants of the
isotherms.
The isotherms for ammonia
nitrogen shown in Figure 8 exhibit
linearity indicative of sorption.
However, the non-linearity of the
potassium isotherm shown in Figure
9 retarded removal at higher
concentrations due to competition
with other ions. Within the scope
of all components analysed, ammonia
nitrogen gave the most desirable
isotherm configuration and potassium
ion the least. Predictions were
undertaken for both ions.
I.Or
0-8
C/Co
O6
0.4
O2
THEORETICAL DILUTION CURVE
o OBSERVED BREAKTHROUGH
CHLOR DE
x OBSERVED BREAKTHROUGH
AMMONIA NITROGEN
p PREDICTED BREAKTHROUGH
AMMONIA NITROGEN
400 800 1200 1500 2GOO 2400
COLUMN DISCHARGE VOLUME (ml)
2800
Figure 9. Observed and predicted
breakthrough curves for
chloride and ammonia
nitrogen.
The isotherms were used to
predict concentration breakthrough
curves for the column described
previously. These would be used
in comparison with the actual
breakthrough curves of the column.
Prediction of the column breakthrough
curves took into account the dilution
provided by the soil water within
the column by assuming a complete
intermixing of chemical components
of the water and the migrating
liquid. An incremental analysis
was used by considering units of
147.3 ml of soil water and the
corresponding 1184.3 g of dry soil.
The estimated porosity of 0.45 was
used to determine the amount of
liquid to be used in the intermixing
calculations. These were 124 ml
initially and 100 ml after the soil
reached field capacity. Iteration
was necessary to determine the
operating point on the removal
isotherm.
The observed and predicted
breakthrough curves for chloride
ion and ammonia nitrogen of the
soil 3 column are shown in Figure
9. The predicted chloride ion
breakthrougli curve is in fact the
theoretical dilution curve. The
mass attenuation to breakthrough
including dilution by the soil water
for the chloride and ammonia nitrogen
is given below:
Item:
Observed
chloride
Predicted
chloride
Observed
ammonia
Predicted
ammonia
Mass attenuated,
mg/1000 g dry soil
88.17
110.42
178.30
233.00
Comparison of the observed
and predicted data exhibits fair
agreement. As discussed previously,
the lack of fit has been attributed
to incomplete intermixing of the
components of the leachate and the
soil water.
It has been assumed that the
ratio of the observed chloride
attenuation to the predicted chloride
65
-------
attenuation would describe the
degree of incomplete intermixing.
This assumption postulates that
chloride is not attenuated by the
soil by mechanisms other than
dilution.
Therefore, it should be pos-
sible to use the above chloride
ratio as a correction factor on
the predicted ammonia breakthrough
curve. In fact, the observed
chloride to predicted chloride mass
attenuation is 0.798 whereas the
observed ammonia to predicted ammonia
mass attenuation is 0.765. There-
fore, the predicted ammonia curve
corrected by a factor of 0.798 would
result in a good approximation of
the observed ammonia breakthrough
curve.
The observed and predicted
potassium ion breakthrough curves
in the column are shown in Figure
10, along with the theoretical
dilution curve. The fit in this
case is poor. This is because the
sequential removal of potassium
ion and the probable desorption
of this ion were not accounted for
accurately in the calculations.
The mass attenuation to breakthrough
including dilution by the soil water
for the chloride and potassium ion
is given below:
I tern:
Observed
chloride
Predicted
chloride
Observed
potassium
Predicted
potassium
Mass attenuated,
mg/1000 g dry soil
88.17
110.42
402.00
303.00
In the case of potassium, the
correction of the predicted potassium
breakthrough curve cannot be
accomplished by the use of the
chloride ratio 0.798, which describes
the degree of incomplete intermixing.
OS
C/C0
0-6
0.4
0-2
A THEORETICAL DILUTION CURVE
x OBSERVED BREAKTHROUGH CURVE
D PREDICTED BREAKTHROUGH CURVE
J_
0 4OO 800 1200 EDO 2000 240C
COLUMN DISCHARGE VOLUME (ml)
Figure 10. Observed and predicted
breakthrough curves for
potassium.
The results of the above
calculations show that reasonable
capability to predict column
breakthrough curves from batch
removal isotherm data exists provided
that the isotherms are linear and
that the degree of intermixing of
leachate and soil water can be
estimated. Additional research
in this regard is continuing.
An alternative means of
comparing column and dispersed soil
experiments was sought to overcome
the uncertainty associated with
the interpretation of the nonlinear
removal isotherm data. In this
case, the ratio of discharge
concentration (C) to the leachate
concentration (CQ) was plotted
against the dry soil weight to
leachate volume ratio. An accounting
was made of the original leachate
contaminant mass and volume during
movement through the column and
through the sequence of dispersed
soil reactors. At each point in
the incremented analysis, the
residual leachate contaminant mass
and volume were calculated. This
was done by considering the influence
of dilution due to the intermixing
of contaminants with the soil water,
the retention of liquid within the
soil, and the addition of water
to retain sufficient liquid volume
in the dispersed soil reactors.
66
-------
The data generated represented the
change in contaminant concentrations
in the original leachate due only
to interaction with the soil as
a function of the dry soil weight
to leachate volume ratio. Such
calculations were prepared for
chloride, ammonia nitrogen, total
iron, and COD. The data arc shown
in Figures 11 through 14, inclusive.
i.o
0-8
C/Co
0-6 -
I
0.4|-
COLUMN
BATCH I
BATCH 2
0-2!-
C 10 20 30 40 50
SOIL/ LEACHATE (grn/ml }
Figure 11. Discharge concentration vs
soil to leachate ratio.
Chloride.
1.0 r
0-8
C/C0
0-6
0.4
0-2
COLUMN
BATCH I a 2
Note: Botch land 2 curves are
coincident
10
20 30 40 50
SOIL/ LEACHATE (?m/ml)
Figure 12. Discharge concentration vs
soil to leachate ratio.
Ammonia nitrogen.
COLUMN
BATCH I
BATCH 2
0 10 20 30 40 50
SOIL / LEACHATE (gm/mi )
Figure 13. Discharge concentration vs
soil to leachate ratio.
Total iron.
0-6-
0-4
0-2
COLUMN
BATCH I
J_
0 10 20 :iO 40 50
SOIL/ LEACHATE (gm/ml )
Figure 14. Discharge concentration vs
soil to leachate ratio.
Chemical oxygen demand.
Figure 11 gives a comparison
between the column behaviour and
the results of two dispersed soil
experiments for chloride. Batch
1 refers to the first dispersed
soil experiment in which a slug
of leachate was passed sequentially
through a series of 10 dispersed
soil reactors. Batch 2 refers to
a second dispersed soil experiment
in which the same 10 reactors were
exposed to a second slug of leachate.
As expected, the data show that,
67
-------
in the absence of dilution, C/Co
for chloride remained constant at
1.0 independent of the soil to
leachate (g/ml) ratio. Good
agreement between column and
dispersed soil behaviour is evident.
The interaction of ammonia
nitrogen and the soil is shown in
Figure 12. Reasonable agreement
between the column and Batch 1 is
exhibited. The column concentrations
are somewhat greater than those
of Batch 1. The reason for this
difference is not apparent at this
time. The degree of intermixing
between the constituent of the soil
water and migrating liquid in the
column was shown to be incomplete
upon consideration of the theoretical
dilution. Thus the average
concentration of ammonia in the
soil water would be less than that
of the migrating liquid and according
to the removal isotherm in Figure
7 this could result in reduced
ammonia removal and increased values
of C/CQ. In contrast, it is likely
that, in the dispersed soil
experiments, the degree of component
intermixing would be greater than
that of the column because of the
dispersed condition. Some of the
difference may be attributable to
this.
The data in Figure 12 show
that significant removal of ammonia
occurs to the point of complete
removal as the ratio of soil to
leachate increases. In reality,
the concentrations reduce more
quickly by virtue of contaminant
intermixing with the soil water,
a condition which has been removed
from the calculations used to prepare
Figures 11 to 14. Figure 12 shows
that ammonia removal also occurred
in batch 2 where the soil in the
dispersed reactor was exposed to
a second slug of leachate. However,
the extent of the removal at a given
soil to leachate ratio was less
than that in batch 1 due presumably
to a reduction in removal capacity
with increasing amounts removed.
A somewhat similar situation
exists for iron removal as shown
in Figure 13. However, a difference
in removal between batches 1 and
2 did not exist. This nay be because
the removal mechanism included
precipitation as opposed to simply
sorption, the probable mechanism
for ammonia removal.
The data in Figure 14 shov;
reasonable agreement between COD
removal in the column and batch
experiments. However, very little
removal occurs in either case.
The flow-through times in the column
were short, only a matter of hours.
Thus, the opportunity for
establishing an active microbial
community suitable for the
decomposition of migrating organic
matter would be small. However,
in a field situation with longer
contact times, microbial activity
could be significant. In such
cases, the dispersed soil reactors
would not provide adequate
information for the removal of
organics.
With the exception of being
unable to account for microbial
activity, the results of this
analysis show that dispersed soil
experiments can be used to provide
an approximate estimate of column
behaviour. Based on the comparisons
between the undisturbed and remoulded
soil column results discussed earlier
and by including in the analysis
the influence of constituent
intermixing between leachate and
soil water, it would appear that
the dispersed soil experiments can
be used to approximate the behaviour
of contaminants in the soil.
SUMMARY AND CONCLUSIONS
The potential to pollute the
environment does exist with the
disposal of waste on the land.
At present, it is not possible to
quantitatively estimate the pollution
potential. To do this it would
be necessary to predict the behaviour
patterns of contaminant migration
in the soil. The purpose of this
paper was to develop and evaluate
technology suitable for quantitative
estimation of contaminant migration.
68
-------
The major constraints on a
prediction model were considered
to be the difficulty in simulating
flow conditions similar to those
in the field and the time needed
to generate the necessary attenuation
information. To this end, a series
of laboratory experiments were
designed to evaluate a suitable
technological approach.
The experiments have been
described in the paper.
The following observations
and conclusions were formulated:
1. A significant degree of
attenuation by dilution
is provided by the water
retained in the soil below
the field capacity. The
theoretical dilution
provided by soils 1 to
3 were calculated to be
151.76, 139.23, and 110.42
mg/1000 g dry soil,
respectively. The measured
dilution provided was
observed to be 110.84 and
112.84 mg/1000 g for the
undisturbed and remoulded
soil 1, respectively; 27.89
and 54.90 mg/1000 g for
the undisturbed and
remoulded soil 2,
respectively; and 88.17
mg/1000 g for the remoulded
soil 3.
It was observed that the
remoulded soils provided
more attenuation by dilution
than did the undisturbed
soils and that the soils
with the greater content
in soil particles of size
.074 mm provided the highest
ratio of observed to
theoretical dilution.
2. When flow conditions are
intergranular, the use
of remoulded soil columns
to estimate attenuation
appears to be acceptable.
Therefore, the estimation
of attenuation using
dispersed soil reactors
corrected for the degree
of dilution provided as
calculated from the
remoulded soil column would
be acceptable. This was
observed to be so when
the ratio C/CQ was plotted
against the ratio of dry
soil weight to leachate
volume for the dispersed
soil and remoulded column
studies. In this case,
good agreement was observed
for chloride, ammonia
nitrogen, chemical demand,
and iron.
3. Removal isotherms
constructed from the
dispersed soil studies
can be used to predict
the breakthrough curves
for some contaminants
resulting from remoulded
soil column experiments.
At present, it appears
this can be accomplished
for contaminants where
the isotherms constructed
from the dispersed soil
studies are linear, such
as ammonium ion. However,
more study is needed before
nonlinear isotherms, which
describe retarded removal
of a contaminant such as
potassium ion, can be used
with any degree of accuracy
for prediction.
69
-------
REFERENCES °-
1. Matthess, G. "Hydrogeologic 7.
Criteria for the Self-
purification of Polluted
Groundwater," Int. Geol. Congr., 8.
24th Sess., Sect. 2,
Hydrogeology, Canada, pp. 296-
303, 1972. 9.
2. Farquhar, G. J., F. A. Rovers,
R. N. Farvolden, and H. M.
Hill. "Sanitary Landfill Study,
Final Report Vol. I, Field 10.
Studies on Groundwater
Contamination from Sanitary
Landfills," University of
Waterloo Research Institute,
1972.
3. Hughes, G. M., R. A. Landon, 11<
and R. H. Farvolden.
"Hydrogeology of Solid Waste
Disposal Sites in Northeastern
Illinois, A Final Report on 12.
a Solid Waste Demonstration
Grant Project," Illinois State
Geological Survey, Urbana,
111., U.S. Environmental
Protection Agency, 1971. 13.
4. Rovers, F. A., G. J. Farquhar,
and J. P. Nunan. "Landfill
Contaminant Flux-Surface and
Subsurface Behavior," 21st
Industrial Waste Conference, 14.
Toronto, June 1973.
5. Personal Communication EPA,
U.S.A., Sponsored Study, 15,
Illinois State Geological
Survey, Urbana, Illinois.
Personal Communication EPA,
U.S.A., Sponsored Study,
University of Arizona, Arizona.
Personal Communication EPA,
U.S.A., Sponsored Study, Dugway
Proving Grounds, U.S.A.
Farquhar, G. J., and F. A.
Rovers. "Industrial Waste
Study," University of Waterloo.
Rovers, F. A., and G. J.
Farquhar. "Contaminant
Attenuation in Soil," University
of Waterloo.
Drcwry, W. A. "An Experimental
and Theoretical Study of the
Movement of Viruses in
Groundwater," Ph.D.
Dissertation, Stanford
University, 1968.
Personal Communication with
Lc Webber, Professor, Department
of Soil Science, University
of Guelph, Guelph, Ontario.
LeGrand, H. E. "System for
Evaluation of Contaminant
Potential of Some Waste Disposal
Sites," Journal AWWA, August
1964.
Apgar, M. A., and Langmuir,
D. "Groundwater Pollution
Potential of a Landfill Above
the Water Table," Ground Water,
9, (6), 1971.
Bear, F. E. "Chemistry of the
Soil," Reinhold Publishing
Corporation, 1964.
Alexander, Martin, "flicrobial
Ecology," John Wiley § Sons,
Inc.,1971.
70
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VARIATIONS IN GAS AND LEACHATE PRODUCTION FROM
BALED AND NON-BALED MUNICIPAL REFUSE
Melvin C. Eifert
Systems Technology Corporation
Dayton, Ohio
OBJECTIVES OF THE STUDY EFFORT
Disposal of refuse in a landfill
leads to a number of problems related
to the design and operation of the
landfill site. The major problems
related to landfill situations are
basically operational. In addition
to these, however, there are two
other problems which must be
addressed to properly maintain and
understand the situation that is
occurring in the landfill itself.
These are gas generation and leachate
production. Solid waste, in a
landfill consisting of primarily
municipal solid waste, decomposes
under initially aerobic conditions
and then under anaerobic conditions
as the oxygen is exhausted. This
process yields gas in the form of
methane, carbon dioxide, and other
gases, such as hydrogen sulfide;
and it produces leachate, a complex
aqueous solution of dissolved and
suspended organic and inorganic
compounds and microorganisms.
The gases generated are a
problem in the immediate vicinity
of the landfill primarily because
of the methane content. Methane,
in concentrations of 5% to 155 with
oxygen in the air, forms an explosive
combination. Thus, it is of some
interest to determine the amount
of methane produced and the rate
at which it is produced. These
data are needed to predict its
migration through soils. To do
this, however, it is also necessary
to know the quantitative and
qualitative production rates of
the other gaseous constituents.
Leachate is, similarly, an
environmental threat associated
with landfills. As a liquid, it
can travel through or over the soils
and contaminate both surface and
groundwaters.
The goals of the program I
am describing to you today are (l)to
determine the production rate of
gas from a landfill in a qualitative
sense (that is, identify what gases
are present) and in a quantitative
sense (that is, determine the gas
production rate); and (2) to
characterize leachate produced from
simulated landfills during the
course of the program in terms of
its quality (what constituents are
present) and the quantity (how much
is produced). Ultimately, the data
on gas generation will be used in
models for predicting landfill gas
migration--models that can be used
to predict the hazards associated
with landfill gas production.
The method to be used for
accomplishing these goals was to
design and construct five landfill
simulators, fill with municipal
refuse, and then monitor for
temperature, moisture, pressure,
leachate, and gas production. The
test cells contain unprocessed raw
refuse, processed raw refuse, baled
unprocessed raw refuse, baled
processed raw refuse, and baled
unprocessed raw refuse in a saturated
environment. The use of all forms
71
-------
of landfilled solid waste will
provide a basis for comparing the
Us and Icachate production rates
under these various conditions.
During the course of the effort,
Hata will be collected on the various
parameters associated with the test
cells and analyzed on an on-going
basis. At the end of the program,
the data will be compiled and
analyzed to determine trends to
compare the simulated landfilling
methods, to define the qualitative
production of gases and leachate,
and to nake recommendations based
on the analysis of the data.
To this date, the solid waste
has been placed in the test cells
and the monitoring of the gas and
leachate has begun,, In the following
sections of this paper, the design
and construction phase, the cell
loading phase, and the initial data
from the monitoring of the
temperature, gas, and leachate
systems are described.
FACILITY DESIGN AMD
CONSTRUCTION PHASE
The basic design criteria were
to provide a test facility that
would permit the simultaneous study
of the quality and quantity of gas
and leachate generation from five
different forms of municipal solid
waste in an environment simulating
a sanitary landfill. To accomplish
this goal, a facility consisting
of five identical test cells and
instrumentation cell was designed.
an
The facility layout (Figure 1)
illustrates the cell arrangement.
Figure 1. Facility layout.
72
-------
VATU SE.A.X.A.&L.E.
COVER > UQC.fc.TE.
PVC
Figure 2. Cell design.
This arrangement provides for good
cell accessibility without creating
instrumentation difficulties or
causing temperature influence
problems between cells. The design
of the test cells (Figure 2) was
determined by both the size of the
baled refuse as well as the require-
ments for compacting refuse in a
test cell. Instrumentation access
was provided by casting sleeves
into the cell walls and then
installing bulkhead fittings. The
test cells were constructed of
reinforced concrete and have inside
dimensions of 7 X 11 X 12 ft (2.1
X 3.4 X 3.7 m). They have 8-in.
(20.3-cm) thick walls and they are
set in a straight line with a 3-
ft 8-in. (1.1-m) clearance between
each cell for a total overall length
O'-t.-
of approximately 55 ft (17 m).
The instrumentation and data
collection cell, which is centrally
located to the test cells, was
designed to contain the terminals
and collection ports for all the
gas, leachate, temperature, and
moisture measuring equipment. It
was designed to permit all data
collection in a central facility
rather than several smaller fac-
ilities. The cell was constructed
similarly to the test cells with
the major variation being that the
inside dimensions are 8 X 8 X 15
ft deep (2.4 X 2.4 X 4.6 m). The
instrumentation cell location is
shown on Figure 1, and the general
instrumentation layout is shown
in Figure 3.
73
-------
WC5T WALL
Figure 3. Instrumentation cell layout.
The materials used in the
development of the test cells were
intended to typify a sanitary land-
fill and still pernit the required
sampling and monitoring. The
contents of the charged cell, as
illustrated in Figure 4, consisted
of: a 6-in. (15.2-cn) base of non-
reactive gravel; three layers of
9-ft (2.7-n) baled, compacted refuse;
12 in. (30.5 en) of compacted clay;
12 in. (30.5 cm) of pea gravel;
and fi in. (15.2 en) of freeboard.
This simulation typifies a
sanitary landfill environment in
that it does contain the compacted
refuse with soil cover and a water
source (a water injection rake
buried in the pea gravel) but differs
because of its small size and sealed
environment. The use of pea and
nonreactive gravel facilitates test-
ing without affecting the analysis
of the data.
The on-site instrumentation
for this facility consists of
temperature, moisture, and gas
monitoring equipment. The temp-
erature monitoring equipment consists
of a total of 120 copper-constant
thermocouples with each cell having
24 probes distributed throughout
the refuse. The extension leads
of each cell's thermocouples are
run through PVC conduit to each
of five separate 24-position selector
switches located in the instrumen-
tation cell. The output of each
of these five selector switches
is connected to another selector
switch whose positions correspond
to the five test cells. The output
of this selector switch is then
connected to a digital readout
temperature indicator. The wiring
and switching arrangement is
schematically shown in Figure 5.
The thermocouple design is
illustrated in Figure 6. The
distribution of the thermocouples
is shown in Figure 7.
74
-------
*«*W&KfcSSWS»S
*Ww**»*i*>'*!M
^*«'a«s»EM^»^»*s«Ki*p»a^«^«^fc«^««a<»\NJG
Figure 6. Thermocouple design.
\ !•- a-
T" t
i
) 1-2.
4
1 i-4.
> ^ • la <
> 7
,,„.
1
> 2-4 <
» Lo <
\i-lo-
4--L,"
O llo
4) \T
T'
t
\
I'-U"
t
'
— -
(
' t& <
,« ..
,w[^_
1 I3.?> 2i
>ta O7&-Z2
1
>Z4
Figure 7. Distribution of the
thermocuples.
75
-------
Figure 8. Moisture probe location.
The moisture monitoring instru-
mentation consists of both gypsum
soil blocks and porous cup
tensiometers. The gypsum soil
blocks operate on the principal
that the moisture in the soil is
absorbed by the gypsum, which
separates two electrodes, and causes
the resistance across these elec-
trodes to change. This change in
resistance is measured on an ohm
meter with a special calibration.
Each cell contains nine of these
probes, and their location in the
refuse is shown in Figure 8. The
extension leads for these probes
are run through the PVC conduit
used for the thermocouples and are
connected to a switching unit sim-
ilar to that described for the
thermocouples.
The porous cup tensiometer
is a unit that measures moisture
availability in the soil to a
pressure of 100 centibars. The
unit consists of an air-tight,
water-filled tube connected to a
porous cup probe. The porous ceramic
probe permits the water in the tube
to flow in and out depending on
the moisture content of the soil.
The moisture content is measured
on a vacuum gage connected to the
water-filled tube. Two of these
units are used in each test cell.
The gas monitoring system
consists of 10 collection probes
for each cell that is connected
to a manifold and valve arrangement
inside the instrumentation cell
and then connected to a precision
wet test gas meter. The gas
collection piping in the test cells
consists of: three rows of three
perforated plastic pipes in the
refuse and one collection port in
the test cell freeboard. The
manifolding is designed to permit
gas collection from any of the three
levels of perforated pipes, the
freeboard area, or any combination
of these two regions. Figure 9
schematically presents this piping
and instrumentation arrangement.
76
-------
PROBC
TVP 3
TRANSPORT
\_\VICS
T CST
\NST.
Figure 9. Gas collection schematic,
CELL LOADING PHASE
Introduction
The effort called for loading
solid waste into five test cells.
The solid waste to be placed in
each of the cells was defined
previously but will again be
identified here: cell 1, baled
shredded refuse; cell 2, baled
unshredded refuse; cell 3, baled
unshredded refuse (saturated); cell
4, shredded raw refuse; and cell
5, unshredded raw refuse.
Initially, all the solid waste
was to be obtained from the City
of Oakwood, Ohio, a suburb of Dayton,
However, during the initial phase
of the effort, it became apparent
that the baler proposed to be used
for baling the solid waste could
not achieve the 1500 Ib/cu yd
compaction density required by the
contract. Hence, a baler had to
be located that would provide this
compaction density.
During this search for the
baler, only two were located that
we believed would provide this
compaction density. One was in
Massachusetts and the other in
Georgia. The Massachusetts baler
facility was experiencing some legal
and operational difficulties and,
hence, it was decided not to use
this facility. A visit to the Cobb
County, Georgia, Baler facility
showed that this facility would
be the most desirable one to use
77
-------
for this study. This baler produced
a baled size of approximately 3
X 3 X 5 ft at a compaction density
of 1600 Ib/cu yd.
The unbaled solid waste, both
shredded and unshredded, was obtained
from the City of Oakwood, Ohio,
as was initially planned. A shredder
at the Montgomery County Incinerator,
Dayton, Ohio, was used to shred
the raw refuse for cell 4. The
contract required a compaction
density of approximately 850 Ib/cu
yd for the shredded and unshredded
raw refuse test cells.
To successfully load test cells
with solid waste, it is necessary
to develop detailed logistics plans.
These plans included a material
requirement plan, an equipment
requirement plan, and a personnel
requirement plan. The material
section of the logistics plan defines
the total quantities of solid waste,
clay, pea gravel, etc., required
to initiate the complete loading
sequence and to specify sources
for each of the materials required.
The equipment section of the
logistics plan identifies the type,
source, and contact for each item
of equipment required for the loading
sequence. This includes hand tools,
rental equipment, and contract
equipment for work performed both
at Dayton, Ohio, and Atlanta,
Georgia. The manpower section
identifies the various tasks involved
in the total operation, identifies
the type of labor required to perform
the task, and the personnel required
to supervise each group of tasks.
Detailed outlines were prepared
for the work effort at both Dayton
and Atlanta.
Another requirement of the
contract called for characterizing
the solid waste at the different
facilities. Hence, provisions had
to be made for hand sorting
approximately 350 to 400 Ib of the
solid waste at each facility from
where waste was obtained. Several
of these sorts were performed to
better categorize the solid waste
used in this study.
Since the baler facility in
Atlanta, Georgia, was not operational
until the middle to end of November
1974, cells 4 and 5 containing the
shredded and unshredded raw refuse
obtained from Oakwood, Ohio, were
loaded first. After the loading
of these two cells, plans were then
made to load the remaining three
cells with the baled solid waste
from Atlanta, Georgia. In the
following sections, the loading
of the test cells, located in
Franklin, Ohio, are described.
Loading of Shredded and Unshredded
Raw Refuse CCells 4 and 5)
The refuse from the City of
Oakwood was delivered to the
Montgomery County South Incinerator
by the City of Oakwood collection
vehicles. Plans were made to shred
the material at the South
Incinerator, perform the 350- to
400-lb hand sorts for waste
characterization, and truck the
shredded refuse to Franklin for
loading into cell 4.
The first cell to be loaded
was the shredded solid waste for
cell 4. However, during the initial
shredding operation at the
incinerator facility, a malfunction
of the shredder caused us to abort
trying to load the shredded refuse
and plans were immediately changed
to load the unshredded cell, cell
5. The solid waste arrived at the
incinerator facility about 1:00
p.m. and cell 5 was loaded by 1:00
a.m. The loading sequence used
was as follows:
1. The solid waste was dumped
on the tipping floor at
the Montgomery County South
Incinerator, mixed, and
a 350- to 400-lb sample
was removed. This material
was then hand sorted for
characterization.
2. The material was loaded
on packer trucks and
transported to Franklin,
Ohio, where it was dumped
on a concrete pad. The
78
-------
vehicles were weighed
before and after leaving
the Montgomery County
Incinerator so that the
weight of the refuse would
be known.
3. A front-end loader at
Franklin placed the refuse
in the cells in ap
proximately 3- to 4-ft
layerso Sample buckets
of the refuse as picked
up by the front-end loader
were weighed; the
approximate weight of each
load being placed in the
test cell was needed so
that the desired compaction
density could be achieved.
4. After the material was
placed in the cell, the
material was compacted
by using a crane and a
wrecking ball modified
with a rectangular plate.
The crane would continually
pick up the wrecking ball
and drop it on the refuse
for compaction.
5. At the required intervals,
as identified in Section
2, instrumentation in the
form of gas probes, ther-
mocouples , and moisture
probes would be placed
in the cells. As soon
as thermocouples were
placed in the cells,
readings would be taken.
6. The above steps continued
until the refuse was
completely placed in the
cells and the desired
compaction density achieved.
The material left on the
pad was weighed so that
the exact weights of the
refuse in the cells could
be obtained.
7. When the solid waste had
reached the desired level
in the test cell, a 1-ft
layer of soil was placed
on the refuse. This soil
8.
was compacted by using
construction-industry-type
road tampers. A water
distribution system was
then installed at the top
surface of the soil layer,
and a 12-in. gravel layer
was then placed on top
of the soil and water rig.
A concrete lid was then
placed on the cell to seal
it.
The only additional steps
needed to load the shredded solid
waste from the City of Oakwood were
that the material had to be shredded
first at the Montgomery County
Incinerator and then loaded on
packer trucks for transportation
to Franklin, Ohio. The test cell
loading sequence was identical.
A compaction density of 840 Ib/cu
yd was achieved for the raw refuse
test cell, and a compaction density
of 929 Ib/cu yd was achieved on
the shredded test cell.
Loading of Cells 1, 2, and 3
The loading of cells 1, 2,
and 3 presented a few more challanges
than did cells 4 and 5. The main
reason for this is that the refuse
had to be trucked from Atlanta,
Georgia, to Franklin, Ohio. Detailed
plans had to be prepared to ensure
that the refuse could be baled and
delivered as quickly as possible.
To provide some insight as to the
logistics problems involved in this
particular effort, the following
discussion is presented.
The baler facility was located
in Marietta, Georgia, a city
northwest of Atlanta, and the
shredder was located southeast of
Atlanta. Provisions had to be made
to haul the shredded refuse to the
baler facility for baling. In
addition, the bales were banded
to ensure that they would be
delivered to Franklin in a baled
condition. A local Atlanta
contractor was retained to band
the bales. So the bales could be
handled easily at Franklin during
the loading of the test cells, a
79
-------
3-in. I-bcaru was banded into the
bale; the bale could then be moved
using the I-beam and a crane.
The hauler of the bales to
Franklin reported to the baler
facility for the loading of the
bales and then immediately took
the bales to the banding subcon-
tractor approximately 20 miles away.
So you can see a good detailed
logistics had to be developed to
ensure the timely removal, baling,
shredding, and delivery of the solid
waste to Franklin, Ohio, for loading
into the test cells.
As discussed previously for
the loading of cells 4 and 5, 300-
to 350-lb hand sorts of the solid
waste had to be performed at both
facilities (shredding and baling).
The sorts were performed using local
labor but with Systech's supervision.
The baling and shredding of
the refuse in Atlanta started on
December 16, 1974, and the cells
were loaded, instrumented, and
sealed by December 20, 1974. The
bales were received in Franklin
on December 19 and 2 days were
required to completely load and
seal the cells. The bales remained
together during the shipment from
Atlanta, and as bales were placed
in the cells, the bands were removed.
The loading and instrumentation
procedures were identical to those
described in the previous section.
SUMMARY OF DATA GATHERED THUS FAR
To this date, little gas has
been generated, and in fact,
insufficient gas has been generated
for analysis. Lcachate has been
gathered several times. It is
believed that the first leachate
collected is the squeezings from
the solid waste during loading.
Further leachates gathered reflect
leachate generated fron moisture
additions. Twenty-four inches of
water will be added to the cells
annually. The following tables
and figure contain some of the
initial data (Tables 1 through 3
and Figures 10 through 12). They
are inclusive at this time, and
no conclusions are drawn because
of the limited amount of data
gathered thus far. They are
presented here for your perusal
and illustrate the type of data
gathering and analysis that will
be performed on the gas and leachate
produced from each of the five test
cells.
80
-------
Table 1. WEIGHT OF MATERIALS PLACED IN TEST CELLS AND DENSITY OF REFUSE
Categories
Silica gravel (lb)
(kg)
Refuse (lb)
(kg)
Clay backfill (lb)
around bales (kg)
0.3 clay cover (lb)
(kg)
Pea gravel (lb)
(kg)
Total (lb)
(kg)
Refuse (Ib/cu yd)
density (kg/cu m)
Cell
1
5,120
2,324
25,600
11,662
30,923
14,039
7,161
3,251
4,197
1,639
73,001
33,142
1,452
853
Cell
2
5,120
2,324
25,600
11,662
30,923
14,039
7,161
3,251
4,197
1,639
73,001
33,142
1,452
853
Cell
3
5,120
2,324
25,600
11,662
30,923
14,039
7,161
3,251
4,197
1,639
73,001
33,142
1,452
853
Cell
4
5,120
2,324
23,840
10,832
--
7,161
3,251
8,393
3,863
44,514
20,270
929
554
Cell
S
5,120
2,324
21,400
9,716
--
7,161
3,251
8,393
3,863
42,074
19,154
840
496
Table 2. CHEMICAL ANALYSIS OF LEACHATE*
Cell
Number
1
2
3
4
5
__^_^w— •»•
pH, Conductivity, COD,
Color S.U.
Clear 5.7
Clear 6.4
Reddish- 6.4
yellow
Clear 5.7
Very 5.8
light
yellow
p mhos
4,100
1,800
3,000
1,500
3,600
mg/SL
455
783
957
164
197
Hardness ,
rig/liter, TOC, Volume,
as CaCo mg/J, t
232 74 1
1,016 360 4
1,320 410 1
588 60 1
480 56 1
*0dor was not detectable for any of the samples.
81
-------
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Cell Iron, Copper, Zinc, Nickel,
mg/t iig/£ mg/|,
1*
2 14 1.0 0.25
3 50 1.0 .20 .25
4 °-5 1-0 ,22 .25
5 °-3 1.0 ,14 .25
*£orUlftereana!ai^le f°T analysis* Cadmium mnd
SO
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'
-------
GAS AND LEACHATE GENERATION IN VARIOUS SOLID WASTE ENVIRONMENTS
• Allen G. Jackson
and
D. R. Streng
Systems Technology Corporation
Dayton, Ohio
INTRODUCTION
The work being performed on
this program consists of a detailed
pilot scale landfill simulation
being performed at the Center Hill,
Cincinnati, Ohio, facilities of
the U.S. Environmental Protection
Agency (EPA). The program is divided
into two phases: Phase I consists
of preparation of 15 test cells
and filling these test cells with
solid waste and selected other
wastes; Phase II consists of
collecting and analyzing data
generated by these cells.
Broadly speaking, the objective
of the program is to study solid
waste decomposition in sanitary
landfills. More specifically, the
objectives are to determine:
1. the effect on gas and
leachate production by
varying the moisture
regimen,
2. the influence of temper-
ature on gas and leachate
production,
3. the effect of wastewater
treatment plant sludges
on solid waste
decomposition,
4. the effect of pH control
on solid waste
decomposition,
5. the effect of premature
wetting on solid waste
decomposition,
6. the effect of hazardous
liquid and sludge wastes
on solid waste decomposi-
tion and the fate of the
hazardous waste,
7. survivability of polio-
virus , and
8. settlement rates for a
variety of environmental
and operational conditions.
Because of the variety of
objectives and the number of cells,
the design of this experiment is
somewhat difficult to grasp quickly.
To assist in clarifying the purpose
of each cell in meeting the objec-
tives presented above, Table 1 shows
the important parameters of each
of the test cells.
Cells 1 through 4 satisfy the
varying rainfall regimen (objective
1); cells 5, 6, and 7 contain sewage
sludge mixed with the solid waste
(objective 3); cell 8 has calcium
carbonate added to the solid waste
(objective 4); cell 11 received
enough dechlorinated water to
simulate 751 of the field capacity
(objective 5); cells 12 through
14, and 17 received hazardous wastes
(objective 6); cells 16 and 17 are
located inside the high bay area
of the Center Hill facility where
83
-------
the environment can be maintained
at room temperature. These two
cells provide the basis for com-
parison to determine the effect
of temperature (objective 2). Cell
15 contained poliovirus inserted
into the solid waste in the cell
(objective 7). All cells have
settlement devices for tracking
the change in height of the solid
waste over the period of the project
(objective 3).
As indicated by the table,
cells 9 and 10 contain no solid
waste. These cells are reserved
for two additional hazardous waste
streams, which, at the time these
cells were filled, were unavailable.
A second loading sequence will begin
on April 1, 1975, during which tine
these cells along with several
others will be charged.
The majority of the cells (1-
15) are located outside, south of
the laboratory building. Their
arrangement is a U-shape to
facilitate loading and optimize
instrumentation connections to the
test shed containing temperature
and gas measuring equipment. Cells
16 and 17 are located inside the
high bay area of the laboratory
where the ambient temperature is
maintained between 65 and 75 F.
DETAILS OF CELL DESIGN
The test cells are 1.8 m (6
ft) in diameter and 3.0 n (12 ft)
deep. They are made of 4. 76-mm
(3/16-in.) steel covered with coal
tar epoxy. The cells outside have
poured concrete bottoms. The two
interior cells have steel bottoms
(which were welded onto the main
tube of the cell). Provisions for
draining leachate have been included
in the bottom of each of the cells.
A depression in the concrete base
contains a 76-mm tube that connects
the cell to the central observation
well. Each of the leachate
collection lines was secured with
ball valves. All leachate is
collected anaerobically by
incorporating a valving system that
allows purging of the piping involved
Table 1. PARAMETERS OF EACH TEST CELL
CtLL NO
4
8.
\Z
15
St WOGE
Si UOut
SEWAGE
SLUDGE
St WAGE
SLUfJGE
C.CO,
EL EX
PLATING
WASTE
"ClNOI
IfiOANIC
IVUEU
WASTE
CHL OPINE
PROD.
BftlNE
SlUDGE
POLIO
VIRUS
SOLVEN'
BASED
PAINT
SLUDGE
2624.'
90J
rjp
T vpf. '
')fj[ N^
CIGSED
OPE V
CLOSED
OMI w^
OPE
CLOSED
SEALED
SEALED
ANNU.V
MOIS1 UFU
6.X
^4064
161/
--M6.1
2B2.I
--100 7.6
282JX'
x^067.e
262
'Top 7.6
2021
I067.(
282^
Ti M('
PdOBES
3 7
3,
MAS,:, »
SOLID .
WA 'J H
6725^-
•'3016
84
-------
with Argon before collection. Steel
lids with manhole covers arc provided
for 12 of the cells. These are
bolted to the cells that are in
the ground or in the high bay by
means of tabs located on the lids
themselves. An airtight seal is
accomplished by caulking.
A gasketed manhole cover is
attached to the cell cover by means
of bolts and welded into the
periphery of the hold provided for
the manhole cover.
Figure 1 shows a cross section
of a test cell* The size of the
test cell and the details of the
cross section were determined by
EPA staff to be suitable for the
purposes of this research effort.
WAIII oisuir lino
Figure 1. Cross section of test cell.
Starting from the bottom of
the cell, the first layer of material
is silica gravel. This serves as
the base for the solid waste and
allows Icachatc to flow through
the drain line. Silica gravel was
chosen to remove any interaction
between the leachate and the gravel
that would compromise the chemical
composition of the leachate.
Above the silica gravel are
eight lifts of solid waste, each
0.3 m (1 ft) in thickness.
Temperature probes are located at
the second, fourth, and sixth lifts,
and gas probes are located at the
second and sixtli lifts and in the
pea gravel cover.
The cover for the solid waste
is clay, 0.3 m (1 ft) thick and
compacted to a predetermined density.
On top of the clay is 0.3 m of
washed pea gravel. T/ithin the pea
gravel is the water distribution
system, which consists of a circular,
perforated polyethylene tube
connected to the outside through
a valve.
LOADING OF THE CELLS
To minimize the exposure time
of the solid waste, the cells were
loaded and sealed in 4 days. The
solid waste was placed in the cells
in eight, 0.3-m (1-ft) increments,
which approximated 407 kg (895 Ib).
From this was removed an 11.4-kg
(25-lb) moisture sample and an 18.2-
kg (40-lb) separation sample.
Compaction was accomplished
using a 1,318-kg (2,900-lb) wrecking
ball supported by a 9-m (30-ft)
boom crane. Densities achieved
averaged 461 ± 12 kg/cu m (778 ±
20 Ib/cu yd). The various materials
under scrutiny (i.e., sludge, etc.)
were added to all lifts except the
first. This was done to eliminate
premature leaching of the materials
present. All sludges were received
several weeks before the loading.
The sewage sludge was obtained on
a daily basis from the City of
Cincinnati. The poliovirus was
inoculated into eight expanded
aluminum baskets and into three
nylon bags containing solid waste
and added at each of three levels
within cell 15. Table 2 lists the
amounts of materials added to the
85
-------
Table 20 MATERIALS ADDED TO TEST CELLS*
Material
addedt
CPBS
SB PS
EW
IPW
Sewage s
Sewage s
Sewage s
Calcium
Water
ludge
ludge
ludge
carbonate
kg
291.3
229.2
170.1
202.9
9.7
29.2
97.2
12.9
184.8
Amount/lift
(7-lift basis)
Ib
642.1
505.2
374.9
447.4
21.4
64.3
214.3
28.5
407.3
liter
171.
171.
171.
171.
--
--
171.
3
3
3
3
3
gal
45.26
45.26
45.26
45.26
--
--
--
--
45.26
Total
amount
kg
2039.
1604.
1190.
1420.
67.
204.
630.
90.
1293.
1
4
7
3
97
4
4
3
6
Ib
4494.
3536 =
2624.
3131.
150
450
1500
200
2851.
4
1
4
9
2
Cell
number
14
17
12
13
5
6
7
8
11
*Also to cell 15 were added eight aluminum baskets and three nylon packets
of refuse inoculated with poliovirus at the 0.61-, 1.22-, and 1.83-m (2-,
4-, and 6-ft) level,,
tCPBS=Chlorine production brine sludge; SBPS=solvent-based paint sludge;
I:W=electroplating waste; and IPW=inorganic paint waste.
various cells. All cells were
weight and height normalized to
ensure the final densities were
approximately the same. Thermo-
couples on the outside cells and
thermistors on the inside cells
were installed in the appropriate
lifts and monitoring of all probes
was begun as soon as they were
covered.
FILLING SEQUENCE
To accomplish filling of the
cell in 4 days, a detailed sequence
was devised that used two 454-kg
(1/2-ton) pickup trucks, a special
weighing platform, a sampling
location, and an unusual compacting
technique.
Use of two trucks allowed
placing a lift every 15 to 20
minutes, or about 40 hours to fill
all cells. On this basis, a double
shift was planned to allow for
delays such as breakdowns, rain,
snow, and other potential delaying
factors.
The filling operation itself
began when a truclcload of refuse
was received at the facility and
then was dumped onto the sort pad.
At this point the bags in the refuse
were slit by hand, and the front-
end loader mixed the refuse to
provide relative uniformity of the
sample. One of the pickup trucks
was then driven onto a specially
prepared weighing platform,
consisting of four 908-kg (2,000-
Ib) capacity scales, one located
at each wheel. A tare weight of
the truck was taken and recorded.
The front-end loader then placed
enough refuse into the truck to
equal 407 kg (895 Ib). A gross
weight on the truck was taken and
recorded. If the net weight was
within 4.5 kg (19 Ib) of that needed,
the truck was driven off to a
sampling station and a second truck
was cycled through.
At the sampling station, an
11.4-kg (25-lb) moisture sample
and an 18.2-kg (40-lb) separation
sample were removed. The weights
were recorded, the bags were tagged,
and removed for separation or storage
at 4 C (41 F). All sample weights
were within 0.45 kg (1 Ib).
The truck was then driven to
the cell area where the refuse was
placed in the cell.
This \\ras done by means of a
86
-------
specially designed dumping device.
Roller skate trays were anchored
to the truck bed by tying one end
to the bed. On top of the rollers
were three plywood sheets hinged
together to provide a flexible hard
surface for a canvas cover. The
cover was large enough to extend
over the bed and the sides of the
truck. The solid vraste was loaded
into the truck and was driven to
the cell. At the cell, four men
grabbed the canvas and pulled the
load of solid waste out of the
truck. After the refuse was in
the cell, it was leveled out so
that it would be reasonably flat
for compacting.
CHARACTERIZING THE SOLID WASTE
Categorization of the solid
waste was accomplished on each lift
for every cell with the waste being
separated into 11 categories. Table
3 shows the 11 sort categories and
an average percent of each category
present. The raw data are available
upon request.
Microbiological analysis on
both the solid waste and leachate
produced to date is completed.
To summarize the data from the
sorts, we have.seen survival of
total coliform, fecal coliform,
and fecal streptococci in all of
the sort categories. This is because
of the inherent mixing of refuse
that occurs both in the home and
as the solid waste is transported.
The largest concentration of total
coliforms and fecal coliforms
occurred in fines, garden waste,
textiles, and paper, in that order.
Fecal streptococci predominated
in ash, rock, dirt, fines, and
garden waste. These results bear
out the mixing theory quite well.
Microbiological assay of the
leachate has generated some
interesting data. The initial
leachate collected indicated high
levels (generally 100,000
colonies/100 ml) of fecal coliforms,
and fecal streptococcus that varied
tremendously. The initial leachate
that was collected is believed to
consist mainly of the squeezings
from the compactive effort upon
the refuse. Analysis of the
leachates which followed have shown
an increasing dieoff of coliforms
in leachate as the cell ages.
Streptococcus remained quite high
for several months but is now
beginning to indicate a decreasing
number of colonies. A comparison
Table 3. CATEGORIZATION SUMMARY
Category
Average percent over fifteen cells by lift
Food
Garden
Paper
Plastic,
rubber,
leather
Textiles
Wood
Metal
Class
Ash, rock,
dirt
Diapers
Fines
7.81
0.30
44.42
6.40
2,77
0.65
10.12
6.79
2.53
1.89
4.25
8.62
15.83
43.24
5.44
2.91
0.85
8.01
6.85
1.23
0.97
2.06
6.69
22.34
36.20
5.36
3.10
0.71
9.04
11.39
1.90
1.14
2.04
5.91
14.72
41.27
7.25
5.83
0.54
7.54
5.77
4.21
4.66
2.28
9.19
19.75
39.06
6.38
3.28
0.89
6.95
7.02
4.34
1.23
1.91
5.47
23.33
36.67
6.78
3.04
0.79
8.99
7.37
1.96
1.25
4.34
9.64
9.25
45.38
7.42
5.18
1.60
7.77
5088
2.02
1.99
3.33
6.93
17.04
38.01
7.09
7.38
0.84
7.91
8.28
1.25
1.09
4.16
87
-------
of the most probable number (IIPN)
technique versus the membrane
filtration technique shows much
better recovery on the MPN. Recov-
eries have varied by as much as
100-fold. Unpublished reports have
indicated increased recoveries by
the addition of sodium cthylene-
diaminetctracetrate (Ha2 EDTA) to
the leachatcs. We have tried the
recommended Na2 EDTA along with
and have seen no increase
in recovery as yet.
As metals concentrations
increase in the leachatcs, however,
the EDTA may aid our recoveries.
Additional bacteriological
identification of the leachates
has shown the presence of
Pseudononas, Enterobacter, Proteus,
and various molds „ An assay for
salmonella has proven negative.
No antagonistic effects can be seen
from the hazardous waste cells.
A complete listing of chemical
analyses is shown in Table 4.
A complete chemical analysis of
the hazardous waste is shown in
Table 5.
SOME INITIAL DATA
Since the cells have been
filled for less than 4 months, data
from the experiment are limited.
Temperature data on cells 1-8 and
11-15 have been plotted, and leachate
and gas produced thus far have been
analyzed.
The cells are in the early
stages of methane generation, having
just completed the change from
aerobic to anaerobic condition.
TEMPERATURE DATA
Figure 2 is a plot of
temperature versus time. All
temperature plots are illustrated
as functions of hours after placement
of lift number 1. The data for
cells 1-4 indicate that the maximum
temperature was reached about 45
to 60 hr after placement. Cells
1-4 and 15 received solid waste
only, and all exhibit comparable
behavior. The temperature increases
as:
U)/t>p a T0 cxp [at exp (At)]
After peaking, the temperature
decreases as:
T (t)/t>p a T [ l-cxp (-bt)]
or approximately in a cooling curve
of a hot body dissipating heat
energy to a heat sink0
Cells 5, 6, and 7 received
sewage sludge in increasing amounts
(See tables). Cells 5 and 6 have
similar behavior, reaching a peak
temperature at about 50 to 55 hr.
After peaking, the temperature dips,
rises slightly, then slowly
decreases. Cell 7, on the other
hand, does not reach a peak
temperature until about 95 hr, after
which there is a slow decrease in
temperature.
Reasons for this, in terms
of the conditions in the cells,
arc not clear at this time. Since
cell 7 received the largest amount
of sludge, the conditions for
reaching maximum were slotted by
the presence of 630 kg of sludge.
Detailed analysis is underway.
Temperature data from cells
8 and 11-14 indicate the curves
suggested by the data points appear
to be very similar. Peak temperature
was reached at about 95 hr in"8
and 11. Cell 12 peaked at 85 hr;
cell 13, at 80 hr; and cell 14,
at 50-60 hr. Differences in cells
12-14 clearly are a result of the
various materials added, vrhereas
cells 8 and 11 are not sensitive
to the materials.
88
-------
Table 4. ANALYTICAL DATA
Material*
SW, HW
sw, HW
L, SW,
L, SW,
SW, HW
SW, IIW
SW, IIW
SW, IIW
SW, HW
SW, HW
SW, IIW
SW, HW
SW, HW
SW, IIW
sw, in;
SW, HW
SW, HW
SW, HW
L, SW,
L, HW
L, HW
L, HW
L, HW,
SW, SS
SW
SW, SS
SW
SW
sv;
SW
sw
HW, SW
, SS
, SS
HW, SS
HW, SS
, SS
, SS
, SS
, SS
, SS
, SS
, SS
, SS
, SS
, SS
, SS
, SS
, SS
, SS
SS
SS
, SS
Analysis
PH
Conductivity
Acidity
Alkalinity
CODt
Hardness
Total P04=
NH3- nitrogen
Organic nitrogen
Nitrate nitrogen
Organic acidsV
Total solids
Dissolved solids
Sulfate
Chloride
Sulfide
Cu, Zn, Ni, Fe
Ca, Mg, Mn, K, Ma
BOD
Pb, Ilg, Be, Se, Cr
CN
Asbestos
Chlorinated hydro-
carbons
Moisture
Ash
Carbon
Lip ids
Sugar
Starch
Protein
Crude fiber
Water solubles
Cells
analyzed
All
All
All
All
All
All
All
All
All
All
All
All
All
All
All
All
All
All
All
11-14,
17 + 4
11-14,
17 + 4
4,12,14
12-14
+ 4
MA
Type of analysis
Electromctric
Conductivity bridge
Potentiometric titration
Potentioraetric titration
Re f 1 ux/ 1 i t r at i on
EDTA titration
Persulfate digestion/
ascorbic acid titration
Specific ion electrode
Kjeldahl digestion
Specific ion electrode
Partition chromatography
Gravimetric
Filtration/gravimetric
Gravimetric
Specific ion electrode
Specific ion electrode
Atomic absorption
Atonic absorption
D.O. probe/incubation
Atomic absorption
Distillation/titration
Electron microscope/x-ray
GC/electron capture
Drying oven
Muffle furnace
Gravimetric
Soxhlet extraction
Ref lux/ titration
An thr one /spcct rone trie
Calculation
Ether extraction/gravi-
metric
Gravimetric
*L=leachate; SW=solid waste; IIW=hazardous waste; SS=sewage sludge.
tCOD analyses will be done on both over-dried and air-dried solid waste
samples.
VOrganic acids may be cancelled on solid waste samples.
89
-------
Table 5. HAZARDOUS V.'ASTH ANALYTICAL DATA
Measurement
Total solids, *
Total volatile
solids, °»
Moisture, £
Cr ng/liter
Ni ng/ liter
Cu Mg/litcr
Fe ng/liter
As ng/liter
Be ng/liter
Se, ng/liter
Cd, ng/liter
Cyanide,
mg/litcr
Pb, ng/liter
Cl, ng/liter
Asbestos ,
fibers/100 g
Solvent
based
paint
s ludpe,
cell 17
75.25
55.31
24.75
75
0.5
2.0
150
12.8
0.0
7.6
0.5
12.8
*
7500
9
Chlorine
production
brine
sludge ,
cell 14
75o39
1.17
24.11
S.O
65
125
2000
14.5
0.0
16.5
0.7
14.5
*
20.0
110
Electro-
plating
waste,
cell 12
20.47
8.93
79.53
1.56
35
100
1.37
460
0.25
4.5
38.5
460
*
1.35
23
Inorganic
pigment
waste,
cell 13
48.25
25.25
51.75
0.5
10
110
1000
3.4
20.5
16.0
10.5
3.4
*
10.0
45
Petroleum
waste
21.00
31.00
79.00
125
23
3500
5563
1.0
4.8
26.0
0.5
1.0
182
2.35
3
*Not completed yet.
90
-------
33 (901
27 1601
11 (70)
ld> 1401
10 (50)
21 iaoi
22 (701
\b 1401
\0 (501
5 (401
27 (&01
22 (701
ILo 11.01
10 (501
5 (401
27 (&01
11 (701
\b (1*01
iO (501
5 140^
27 (601
2Z (701
U (1.01
1 o 1 501
5 (A HI
32 (501
27 (6>01
22 (701
\1. (U01
\O (501
Cei-\_* \ . 27 1601
* 11 (701
• . H» 11.01 •
10 (501
• 1 ! ^ t/)Q1
\Q ZQ 10 40 50 40 70 BO 30 \QQ HO \ZO 130
CELL'Z , • zl (6°1
" * . 27 (70)
Ms 1401
* 10 (501
t
\0 ZO 30 40 50 40 70 &0 30 \60 UO \Z£> \30
27 (B01
CELL* 1)
• . 17 1701
• * .
I IB (d»01
.
• \0 (501
,
b (401
10 ZO 30 40 50 1.0 10 BO 30 100 \IO \2Q UO zl (B(yi
r 1-v.t.^ .*•... Z2 1701
\U (loOl
\Q 1501
5 (401
\O 20 30 40 50 4O 7O BO) 30 \0b \\0 \70 \3Q '^^^
r CC\-\_* 5 • 2Z (70
* * * •
\U 11.0
Id (50
• S (40
10 20 30 4d 50 40 70 BO 30 \OO \10 \20 \3O
CE\_L»l/>
* t •
•
lOi • 3Pi 4(i 5d 4b 7ft rift 9Ci \r\f\ \\D I7Q l^/^
CEL_L»7
. ' •* •
•
•
ceuL-a
^ * * •
• •
*
>G ZO 30 40 50 4Q 70 BO SO \00 UO, \20 \3Q
CELLL.*\\
• • * *
• . •
*
\0 70 30 40 50 40 70 BO 30 \00 HO 1ZO >3Q
CELL-IZ
• • *
*
. •
IQ 20 30 40 50 l»0 70 BO 30 \00 HO 120 130
CELL»« . . . . . ^
1 • •
•
\0 20 30 4O 50 40 70 &0 30 100 \\0 >20, \iC
VAOURS
HQURS
Figure 2. Temperature of lowest test cell versus time elapsed after refuse
placed in cell.
91
-------
LEACHATE MIGRATION THROUGH SELECTED CLAYS
R. A. Griffin
and
Neil F. Shimp
Illinois State Geological Society
Urbana, Illinois
INTRODUCTION
An investigation of the use
of clay minerals to limit the
pollution of waters by landfill
leachates is being conducted at
the Illinois State Geological Sur-
vey; the study is being supported
in part by a U.S» Environmental
Protection Agency (EPA) contract.
The goal of the project is to
evaluate the potential use of clay
minerals as liners for sanitary
landfills to prevent or mitigate
pollution of ground and surface
waters by liquid effluents from
solid wastes. The results of this
investigation will also find
application in the land disposal
of industrial and power plant wastes.
The research is being conducted
in the Environmental Geology
Laboratory of the Illinois Geological
Survey. The laboratory apparatus
consists of 44 laboratory columns
containing clay minerals and mixtures
of clay minerals through which
leachate was passed. The three
clay minerals used in this study
are kaolinite, montmorillonite,
and illite. The columns were
constructed to simulate the slow,
saturated, anaerobic flow of refuse
effluent as it is thought to occur
at the bottom of a landfill disposal
site.
The refuse leachate used in
this study was collected from the
Du Page County sanitary landfill
near Chicago. The leachate was
passed through two series of columns.
The first series was leached with
sterilized effluent and the second
with natural (microbiologically
active) leachate. The mechanisms
involved in attenuating pollutants,
including microbial activity, by
the three clay minerals were
evaluated. The first step in the
evaluation was a careful chemical
and physical characterization of
the original column contents and
the influent leachate. Analyses
were made for the following: Na,
K, Ca, Mg, Al, Zn, Pb, Cd, Hg, Fe,
Mn, NH4, B, Si, Cl, chemical oxygen
demand (COD), pH, Eh, and
permeability. The original leachate
characterization also included
analysis for Cu, Ni, Cr, As, S,
P04, organic acids, carbonyls, and
carbohydrates. The clays were
characterized for surface area,
cation exchange capacity (CEC),
exchangeable cations, total elemental
content, and bulk density.
The second step was to pass
the leachate through the columns
for periods of time up to 10 months.
During this time effluents from
each column were periodically
collected and measurements were
made for the following: Na, K, Ca,
Mg, Al, Zn, Pb, Cd, Hg, Fe, Mn,
NH4, B, Si, Cl, COD, Eh, pH, and
permeability.
Finally, after leaching was
completed, the columns were sectioned
and the contents analyzed to
determine the vertical distribution
of chemical constituents and particle
sizes in each column.
92
-------
All of the leachate data are
being statistically evaluated, and
predictive equations are being
constructed for estimating the
capacity of earth materials of known
clay mineral composition to attenuate
pollutants. In addition, a series
of separate studies on the capacity
of clays to adsorb eight hazardous
elements (Pb, Cd, Zn, Cu, Cr, As,
Se, and Hg) is being performed.
From these studies, adsorption
isotherms for kaolinite and
montmorillonite are being constructed
to obtain maximum adsorption
capacities under various pH and
ionic competition conditions.
RESULTS OBTAINED TO DATE FROM
COLUMN-LEACHING STUDY
Permeability Measurements
Hydrologic gradient and flow-
rate readings were collected from
the columns for the 10-month period
from February 4, 1974, to December
20, 1974. The data have been
statistically evaluated, and they
indicate that a significant (.01
level) decrease in the permeability
of the columns occurred during the
experiment. Microbiologically
active columns had significantly
larger (.05 level) permeability
reductions than did sterile columns.
Further statistical evaluation
is at present being carried out
to determine the effect of clay
type, clay percentage, and amount
of clay migration on the observed
permeability reductions.
Chemical Data
Chemical analysis of the soluble
fraction of the column effluents
has been completed. It allows us
to make some tentative conclusions
and attenuation rankings of the
clays even though final conclusions
must await completion of analysis
of the "suspended" fraction of
effluent and the column section
samples.
The three clay minerals can
be ranked according to their
attenuating capacity:
montmorillonite > illite > kaolinite.
Montmorillonite attenuates
pollutants approximately four times
better than illite and five times
better than kaolinite. These ratios
are nearly identical with the cation
exchange capacity ratios for the
three clays. The ratios of the
surface area of montmorillonite
to the surface areas of illite and
kaolinite are 1.3 and 2.5, respec-
tively. These data suggest that
surface area is not the property
of the clays that is responsible
for attenuation but rather that
the cation exchange capacity is
probably the principal attenuating
property.
These individual chemical
constituents can be ranked according
to their relative degree of
attenuation by the three clays as
follows:
CKCOD
-------
The constituents Al, Cu, Ni,
Cr, As, S, and PO were found in
such low concentrations in the Du
Page leachate that no attenuation
order could be determined.
The elements for which an at-
tenuation order could be determined
can also be ranked by relative
degree of attenuation as follows:
High Hg, Pb, Zn, Cd
Moderate Si, Mg, K, NH4
Low Na, COD, Cl
No attenuation Ca, Fe, Mn
Measurement of the effluent
concentrations from sand columns,
which contain no measurable cation
exchange capacity, indicates no
Pb or Hg and markedly reduced
concentrations of Zn and Cd eluted
from the columns. These data
indicate that precipitation of heavy
metal hydroxides and carbonates
is an important attenuation
mechanism. This conclusion is
further verified by studies of the
effect of pH on adsorption.
A tentative conclusion from
the column-leaching study thus far
is that the principal mechanisms
affecting pollutant attenuation
by clay minerals in landfill leach-
ates are: a) microbial reduction
of permeability, b) the cation
exchange capacity of the clay, and
c) the effect of pH on the formation
of heavy metal hydroxide and
carbonate precipitates.
HAZARDOUS ELEMENTS
ADSORPTION STUDIES
A hazardous elements adsorption
project, partly supported by the
EPA as an extension of the landfill
leachate project, is also being
conducted at the Survey. The goal
of the second project is to determine
the adsorption capacity of the clay
minerals kaolinite and montmoril-
lonite for eight hazardous elements--
Hg, Pb, Cd, Zn, Cr, Cu, As, and
Se. The adsorption properties of
the clays are being studied over
a wide range of solution
concentrations, competing ion
matrices, and pH values.
The adsorption of Pb, Zn, Cr*3,
Cd, Cr*6, and Se from landfill
leachate by kaolinite and mont-
morillonite clay at pH 5.0 and 25
C has been studied. Character-
ization of As and Hg adsorption,
as well as further studies of the
above elements, is currently in
progress.
Element adsorption is measured
from three solution matrices: pure
water, inorganic salt solutions
similar to leachate in ionic
composition, and landfill leachate
from Du Page County. In addition,
Pb adsorption has also been studied
from Blackwell Forest Preserve
leachate. The nitrate salt of a
metal is added in various concen-
trations to each of the three
solution matrices, and the amounts
adsorbed are measured. The effect
of varying pH on the amounts of
Pb, Zn, Cu, Se, and Cr+6 adsorbed
has also been studied.
The inorganic leachate and
the natural leachate contain all
of the same major cations and anions,
and in approximately the same
concentrations. Any observed
differences between the adsorption
of the metals from the inorganic
leachate solution and that from
the natural leachate solution are
attributed to the presence of the
organic component of the natural
leachate. The amount of metal ion
adsorbed from the pure water solution
is considered to be the maximum
that can be adsorbed under these
experimental conditions.
RESULTS OBTAINED TO DATE FROM
ADSORPTION STUDIES
The adsorption characteristics
of the seven elements investigated
to date are quite similar in many
respects and can be summarized by
the following description. The
amount of metal ion adsorbed by
the clay was about 70S to 80% less
94
-------
from leachate than from pure aqueous
solutions. (It is also interesting
to note here that only about half
as much Pb was adsorbed from
Blackwell leachate as from Du Page
leachate.) This decrease in the
amount of heavy metal sorption has
the environmental consequence that
the metal ions will migrate farther
in landfill leachate than in pure
water solutions of the metal. The
results further show that metal
ions can be expected to migrate
about twice as far in Blackwell
leachate as they would in Du Page
leachate.
The most important factor
affecting the amount of the metal
removed from solution was the pH
of the solution. The five cations
Cr, Cu, Pb, Cd, and Zn showed a
marked increase in adsorption with
increasing pH in the range from
pH 2 to about pH 6. This increase
in adsorption is consistent with
the increase in the pH-dependent
cation exchange capacity of the
clays and with the formation of
metal-hydroxyl complex ions known
to occur in this pH range. Blank
(no clay) solutions carried through
the experiments indicated that the
formation of insoluble carbonate
and hydroxide compounds was initiated
between pH values of 5.5 to 7.5,
depending on the element and its
concentration.
The metals Se and Cr*6 followed
a reverse trend with respect to
pH. Their adsorption increased
as the pH was lowered. Since Se
is known to exist in solution as
the Se04"2 anion and Cr+6 as the
Cr2°7~ anion at low pH values,
this behavior is consistent with
an anion exchange mechanism.
The adsorption maximums
estimated from the isotherms of
the five metal cations adsorbed
from solutions of the pure nitrate
salt of the metal were found to
correspond closely to the cation
exchange capacity of the clay being
used as the adsorbent. This close
correspondence is strong evidence
that cation exchange is the principal
attenuation mechanism at pH values
that preclude precipitation.
Whereas the metal cations
adsorbed to a maximum value that
could be estimated by the CEC of
the clay in pure solutions, the
amounts adsorbed from landfill
leachate, at constant pH, varied
widely. This wide variation is
presumed to be due to the relative
affinity of each metal ion for
exchange sites when competing with
the high concentrations of other
cations present in leachate. A
tentative ranking to indicate the
relative adsorption affinity for
kaolinite at pH 5 of each of the
seven elements studied from Du Page
leachate is given as follows:
Cr*3>Cu=Pb>Cd>Zn>Cr*6>Se.
The adsorption isotherm data
allow us to fit to the equations
that yield reliable predictions
of the amount of metal ion removed
from a solution of known concen-
tration and pH. A computer
simulation model has been written
to predict metal ion migration
through clay columns. The model
is at present being tested on Pb
migration through clay-sand columns.
The tentative conclusion of
the adsorption study is that the
most important factors affecting
the prediction of a given metal
ion's migration under a solid waste
disposal site are the pH of the
solution, the CEC of the clay, and
the ionic composition of the solution
matrix.
95
-------
ORGANIC POLLUTANTS CONTRIBUTED TO GROUNDWATER BY
A LANDFILL
W. J. Dunlap and D. C. Shew
U.S. Environmental Protection Agency
Robert S. Kerr Environmental Research Laboratory
Ada, Oklahoma
J. M. Robertson and C. R. Toussaint
School of Civil Engineering and Environmental Science
ABSTRACT
Organic compounds contributed
to groundwater by a landfill con-
taining refuse deposited below or
near the water were investigated.
Groundwater from a well within the
landfill and a control well was
sampled by modified low-flow carbon
adsorption procedures incorporating
all-glass/Teflon systems to preclude
introduction of extraneous organics.
Column chromatography, solubility
separation, and gas chromatography/
mass spectrometry were employed
for separation, identification,
and quantitation of individual
compounds in organic extracts.
The groundwater was shown to contain
low levels of many undersirable
organic chemicals leached from the
landfill. More than 40 compounds
were identified, most of which were
chemicals commonly employed in
industry for manufacturing many
domestic and commercial products.
The source of these compounds was
apparently manufactured products
discarded in the landfill, since
it had not received appreciable
wastes from industrial operations.
The compounds identified were
believed to be substances leached
very slowly from refuse and/or
transported away from the landfill
very slowly because of adsorption
on aquifer solids. Potential long-
term pollution of groundwater by
industrial organic chemicals from
landfills may be indicated by this
work.
INTRODUCTION
Countless tons of solid waste
have been deposited within the upper
layers of the earth's crust at land
disposal sites throughout the United
States. Within recent years, it
has become increasingly apparent
that this waste poses a potentially
serious threat to the quality of
the Nation's groundwater. This
is especially so because of the
past tendency to locate dumps and
landfills in low-lying areas where
the waste is in contact with or
in close proximity to groundwater.
In a recent study of groundwater
problems in 11 northeastern states,
Miller et al. (1) presented
information on 60 cases in which
landfills were pinpointed as sources
of groundwater pollution and noted
that numerous additional cases of
a similar nature were probably
present in the region. That this
situation is not unique to the
northeast is indicated by a number
of reports from other regions,
including those of Walker (2) ,
Anderson and Dornbush (3), Fuhriman
and Barton (4), Scalf e_t al. (5),
and the California State Department
of Water Resources (6).
Among the many substances that
might possibily enter groundwater
96
-------
by leaching of solid waste are
potentially hazardous organic
compounds, particularly synthetic
organics that may decompose slowly
or be essentially nondegradable
in the subsurface environment.
Until recently, land disposal sites,
regardless of location and design,
have been used for deposition of
practically every kind of solid
waste, including hazardous
industrial, hospital, and agri-
cultural wastes — such as solvents,
plasticizers, phenolic compounds,
and pesticides. Also, the bulk
of waste from great quantities of
products manufactured for domestic
and commercial use has been and
continues to be placed in land
disposal sites, and these products
may contain or have been produced
from a vast array of potentially
hazardous organic chemicals. That
pollution of groundwater by organic
matter leached from solid waste
in land disposal sites can and does
occur has been well documented (3,
6 7), but practically no information
has previously been developed
concerning the nature of the organic
pollutants involved. Clearly, such
information is required for realistic
and comprehensive evaluation of
the threat to groundwater quality
posed by land disposal of solid
waste. The investigation reported
in this paper comprised an effort
to provide such information by
identifying specific organic pol-
lutants contributed to groundwater
by a landfill.
METHODS AND RESULTS
Site of the Study
The landfill chosen for this
study was located at a land disposal
site approximately 1 mile south
of Norman, Oklahoma. This site,
as shown in Figure 1, lies on the
north bank of the South Canadian
River in an area of moderately to
highly permeable soil consisting
of quaternary recent alluvium com-
posed of silt, sand, clay, gravel,
and dune sand.
\
LAND DISPOSAL
SITE"--
1014'
1083
SOUTH
CANADIAN'
RIVER
1082'
„-•-
1081'
SAMPLING WELLS
WATER TABLE
CONTOUR LINE
i 533'
Figure 1. Land disposal site near
Norman, Oklahoma.
The depth of the alluvium, which
lies over a 300-ft impervious layer
of dense clay and chert gravel known
locally as the "red bed," varies
from 35 to 40 ft. The water table
throughout the site is normally
quite high, averaging from 2 to
5 ft below the original land surface
in areas adjacent to the river.
The direction of groundwater flow
was previously determined to be
approximately 7 degrees west of
south, essentially normal to the
water table contours (8). The flow
of the river in the area is very
low except during periods of high
rainfall.
For 38 years, from 1922 to
1960, the City of Norman operated
the site as a dump in which there
were no restrictions concerning
the type of material accepted and
in which open burning was practiced.
In 1960, a trench-type operation
was begun in the area designed as
"Landfill Site" in Figure 1. Layers
97
-------
of refuse were bulldozed into
trenches which had been dug by a
dragline during commercial sand
production. Because of the shallow
depth of groundwater in the area,
large quantities of refuse were
placed below the water table in
most of these trenches. The
deposited refuse was eventually
covered with approximately 6 in.
of relatively permeable fine sand
obtained in the area. In 1972,
because of new state solid waste
legislation, a modified area fill
operation was initiated in which
solid waste was deposited at least
2 ft above the water table and
covered at least weekly. At present,
deposited waste is covered almost
daily and the site is classified
as a sanitary landfill^
Sampling of Organics in Groundwater
Groundwaters from a well located
in the southeast part of the landfill
(designated well No. 3, Figure 1)
and from a control well (located
approximately 0.7 mile from the
upstream edge of the landfill and
1.3 miles northwest of well No.
3) were the waters subjected to
most intensive analysis in this
investigation. Well No. 3, drilled
in November 1972, was cased to a
depth of 32 ft and perforated in
the lower 12 ft of casing. It
contained 17 ft of standing water
at the time of sampling and was
expected to yield groundwater
contaminated by solid waste since
it passed through a layer of refuse
20 to 22 ft thick. The control
well, drilled in October 1973, was
cased to a depth of 42 ft and
perforated in the lower 12 ft.
It contained 37 ft of standing water
and was expected to yield water
unaffected by the landfill because
of its location. Both wells were
carefully drilled and cased and
were thoroughly bailed and pumped
after construction. The wells were
also thoroughly pumped before
sampling to remove standing water
and allow fresh formation water
to enter the well bores.
The two wells were sampled
simultaneously by identical
procedures so that comparison of
organic matter from the control
and landfill wells would clearly
reveal the extent and nature of
organic contamination of groundwater
by the landfill and provide a guide
for selection of compounds that
should receive priority attention
in identification studies. The
sampling procedures employed during
this work incorporated a modified
version of the low-flow carbon
adsorption method (9, 10), with
the groundwater being pumped from
the saturated zone directly through
columns containing activated carbon
to adsorb and recover the organic
compounds. Single-piece all-glass
columns fabricated from 3-in.-
diameter borosilicate tubing were
used. They were packed with 18
in. of 30-mesh activated carbon
(Nuchar C-190, Plus 30, Hebert
Chemical Co., St. Bernard, Ohio)
held in place by solvent-washed
glass-wool plugs. For sampling,
a packed column was placed in a
vertical position at the top of
the casing of each well. Suitable
lengths of Teflon tubing were
attached to the bottom inlets of
the columns and extended down the
well shafts into the saturated zone.
The groundwater was then pumped
up the tubing and through the carbon
columns by variable-speed
peristaltic-type pumps ("Masterflex"
7545 Variable Speed Drive with 7014
pump head, Cole-Parmer Instrument
Co., Chicago, 111.) attached by
Teflon tubing to the outlet
(downstream) ends of the columns.
Power was provided to the pumps
at the field sites by portable
gasoline-operated 1500-watt AC
generators. The variable speed
pumps permitted sustained pumping
of groundwater from the water table
through the carbon adsorption columns
at accurately controlled, constant,
low-flow rates. Flow rates and
quantities of water sampled were
verified by collecting discharge
water from the pumps and measuring
the volumes. A sampling system
in operation is shown graphically
in Figure 2.
98
-------
TIFLON_
TUBE
_COLLICTION
VISSIL fOK
iA.Mpt.tD WATH
-TIFLOM TUB!
- WAT III TAIL!
-(MOUND WATIH
Figure 2. Groundwater sampling
system.
Groundwater was pumped for
each of the two wells through
essentially identical carbon columns
for 126 hr at a rate of 100 ml/min.
In this manner, 200 gal (757 liters)
of water was sampled at each
location. Use of the sampling
systems consisting only of glass
and Teflon from the saturated zone
to the outlet of the carbon
adsorption column and placement
of the pump on the downstream side
of the column virtually precluded
introduction of organic contaminants
during the sampling operation.
Desorption of the Sampled Organic
Material
Upon completion of sampling,
the carbon columns containing the
adsorbed organics from the water
from well No. 3 and the control
well were drained to remove excess
water, sealed with solvent-washed
aluminum foil, and transported
immediately to the laboratory for
processing. A third carbon column,
which had been prepared identically
and at the same time as the columns
used for sampling but which did
not have any water passed through
it, was processed with the sampling
columns to serve as a blank.
The glass columns were scored
with a glass saw and then were
carefully broken open to permit
removal of the carbon in a special
carbon-handling room designed to
minimize the potential for
contamination of the carbon during
processing. The carbon was carefully
transferred to Pyrex glass dishes
and dried at approximately 40 C
for 48 hr under a gentle flow of
clean air in a Precision-Freas
mechanical convection oven (Model
845, Precision Scientific Company,
Chicago, 111.). The air inlet of
the oven was equipped with a carbon
filter to prevent contamination
from the atmosphere.
The dried carbon was transferred
to 2200-ml modified Soxhlet
extractors and extracted for 48
hr with chloroform. The carbon
chloroform extracts obtained from
the blank carbon and the carbon
employed in sampling well no. 3
and the control well were designated
CCEB, CCE3II, and CCEC, respectively.
These extracts were filtered through
solvent-extracted glass-fiber filters
to remove carbon fines and then
vacuum concentrated in rotary
evaporators at temperatures not
exceeding 27 C to a final volume
of 3 ml each.
The chloroform-extracted carbon
samples were dried in the Soxhlet
extractors by passing a gentle
stream of warm, dry air through
the extractions chambers via the
siphon tubes for 20 hr. The carbon
was then extracted for 32 hr with
pure ethanol, and the carbon alcohol
extracts (CAE's) were filtered and
concentrated in the same manner
as the CCE's. However, it was
necessary to filter the CAE's through
extracted glass-fiber filters when
volumes of about 10 ml had been
attained to remove precipitated
material. These precipitates,
together with solid material that
had precipitated on the flask walls
during evaporation, were dried and
weighed. The filtered CAE's were
then further evaporated to the
following final volumes: 4.0 ml
for CAE3II, from well No. 3; 2.0
ml for CAEC, from the control well;
and, 1.0 ml for CAEB, from the
blank.
99
-------
Table 1. WEIGHTS OF CARBON CHLOROFORM AND CARBON ALCOHOL EXTRACTS
Weight of CCE
Weight of CAE
Weight of
CCE + CAE
Source Total, mg mg/£ Total, mg mg/i Total, mg mg/£
Well No
Control
Control
, 3
well
blank
304
11
2
.5
.9
.6
0
0
0
.402
.016
.003*
1219
314
262
.1
.2
.5
1.
0.
0.
610
415
347*
1523.6
326.1
264.8
2.013
0.431
0.350*
Calculated as if this carbon had actually been employed for sampling of
757 of water.
Comparison of CCE's and CAE's
Visual comparison of the various
CCE's and CAE's showed CCE3II, pre-
pared from groundwater from well
No. 3, to be deep yellow, whereas
CCEC, from the control well water,
was light yellow, and CCEB, from
the carbon blank, was practically
colorless. Similarly, CAE3II was
deep yellow-orange, CAEC was yellow,
and CAEB was pale yellow. Both
CCE3II and CAE3II were very odorous,
and the control and blank CCE's
and CAE's were essentially odorless.
Aliquots of each of the
concentrated CCE's and CAE's were
carefully evaporated to dryness
in tared foil cups to determine
the weights of soluble material
dissolved in the concentrates.
Total weights of the CCE's and CAE's
were calculated from these weights
and the weights of material that
had precipitated during preparation
of the concentrated extracts. The
data obtained, presented in Table
1 both in terms of total weights
and weights per liter of sampled
water, showed CCE3II to contain
approximately 25 times as much
material as CCEC and more than 100
times the weight of material in
CCEB; these data also revealed
CAE3II to contain about four times
the material contained by CAEC,
the control, and about six times
the material contained by CAEB,
the blank. Hence, the presence
of much greater quantities of organic
constituents in the groundwater
in the locale of the Norman landfill
than in groundwater from the same
aquifer approximately 1 mile upstream
from the landfill perimeter was
clearly indicated.
The various CCE's and CAE's
were next compared by gas liquid
chromatography. Figures 3 through
6 show chromatograms obtained by
chromatographing, under identical
conditions, aliquots of CCE3II and
CCEC representing 190 ml of
groundwater from well no. 3 and
the control well, respectively,
and aliquots of CAE3II and CAEC
representing 380 ml of groundwater
from these wells. Analogous
chromatography of suitable aliquots
of CCEB and CAEB from the carbon
blank produced chromatograms (not
shown here) that were very similar
to those obtained for CCEC and CAEB.
These chromatographic comparisons
revealed that the groundwater from
the landfill contained a complex
array of organic compounds that
were readily amenable to gas
chromatography and that were either
not present or were present in very
much less quantity in groundwater
not subject to the influence of
the landfill. It was obvious that
practically all of the major organic
components of CCE3II and CAE3II,
which were sufficiently volatile
100
-------
»! ,!/'• 1, j 4 - '
f T^tf 1 ',-* liWlffi CS
t' » W
, e.w s r/s:
Figure 3, of
CCE5II, well.
4. Gas of
CCEC, well.
. Is
I . - 1
Figure 5. of
CAE3I1, well,
Figure 6, cliromatogram o£
CAEC, control well.
101
-------
for gas chromatography, had been
contributed to the groundwater by
the landfill, and identification
of any of these compounds would,
therefore, be helpful in elucidating
the effect of the landfill on
groundwater.
Further Fractionation of the CCE
and CAE from the Landfill Well
CCE3II was subjected to liquid-
solid chromatography on micro silica
gel columns to obtain fractions
of less complexity for further
study. Initially, a ?•-• by 76-mm
column of 100/200 mesh Silicar CC-
7 (Mallinckrodt Chemical Works,
St. Louis, Mo.) was prepared by
dry packing and subsequent washing
with hexane to wet the column and
determine the void volume. A 1.5-
ml aliquot of CCE3II was charged
to the column by carefully adsorbing
it on a small portion of Silicar
CO7, suspending the Silicar
containing the adsorbed CCE in a
small quantity of hexane, and
carefully placing this suspension
on top of the column. The column
was eluted successively with 8 ml
each of hexane, benzene, and
chloroform-methanol (1:1), followed
by 5 ml of methanol. The fractions
of 2 or 3 ml each were collected
after a volume of hexane equivalent
to the void volume had been eluted.
These fractions were designated
CCE3II-SG1 through 10, as shown
in Table 2.
The 10 fractions from the
silica gel column were each carefully
concentrated to a volume of 1 ml
in a rotary evaporator. The
concentrated fractions, together
with the hexane representing the
void volume of the column, were
then examined by gas chromatography.
Fractions CCE3II-SG4, 5, 6, and
7 were found to contain sufficient
quantities of organic compounds
to warrant further study, with
fractions SG4, 5, and 6 appearing
amenable to conclusive investigation
without additional purification.
Fraction CCE3II-SG7, which contained
a very significant portion of the
organic compounds of the parent
CCE, was quite complex and hence
was rechromatographed on a fresh
7 by 76-mm column of Silicar CC-
7. Elution was accomplished with
a total volume of 370 ml of solvent
ranging in polarity from hexane
to methanol, with 26 fractions being
collected as shown in Table 3.
Collection of fractions and the
sequence of eluting solvents were
based partially on the movement
from the column of fluorescent
zones, which were detected under
366 nm uv light. The fractions
were examined by gas chromatography,
Table 2. FRACTIONS PREPARED FROM CCE3II BY SILICA GEL
COLUMN CHROMATOGRAPHY
Fraction
Total volume
Eluting solvents
CCE3II-SG1
CCE3II-SG2
CCE3II-SG3
CCE3II-SG4
CCE3II-SG5
CCE3II-SG6
CCE3II-SG7
CCE3II-SG8
CCE3II-SG9
CCE3II-SG10
2 ml
3 ml
3 ml
2 ml
3 ml
3 ml
2 ml
3 ml
3 ml
5 ml
Hexane
Hexane
Hexane
Benzene
Benzene
Benzene
Chloroform-Methanol
Chloroform- Methanol
Chloroform-Methanol
Methanol
(1:1)
(1:1)
(1:1)
102
-------
Table 3. FRACTIONS PREPARED FROM CCE3II-PG7
BY SILICA GEL COLHMN CHROMATOGRAPHY
fraction
CCE3II-SG7-SG1*
11 SG2*
" SO 3*
SG4t
" SG5t
" SC6t
" SG7
" FG8
" SG9V
" SGI Of
" SGI If
" SG12
" SGI 3
" SGI 4 6
" SGI 5 6
" SG166
" SG176
" SG186
" SH196
" SG206
" SG21
" SG22
" SG23V
" SG24V
11 SG25V
" SG267
Total
volume,
ml
10
10
10
10
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
Flutina solvents
Hex an e
Hex an e
Hexane
Hexane
Hexane, 10 1*1
Hexane-Benzene (1 :1) , 5 ml
Hexane-Benzene (1:1)
Hexane-Benzene (1:1)
Hexane-Benzene (1:1), 5 ml
Hexane-Renzene (1:3), 10 ml
Hexane-Benzene (1:3), 10 ml
Benzene, 5 ml
Benzene
Benzene
Benzene
Benzene-Chloroform (3:1)
Benzene-CM orof orn (3:1)
Benzene-Chloroform (3:1), 10 ml
Benzene-Choloro-Porm (1:1), 5 ml
Benzene-Ch] orof orm (1:1)
Benzene-Chloroform (1:1)
Benzene-Chloroform (1:1), 5 ml
Benzene-Chloroform (1:3), 10 ml
Benzene-Chloroform (1:3)
Benzene-Chloroform (1:3)
Chloroform.
Chloroform
Chloroform, 5 ml
Chloroform-Methanol (1:1), 10ml
Chloroform-Methanol (1:1)
Vethanol
Methanol
* Recomhined as CCE3II-SC7-srl-*3.
t Recomhined as CCE3Il-SG7-SG4-*-6.
f Pecombined as CCE3II-SG7-SG9-*-!!.
fi Recomhined as CCE3II-sr7-SGl4*20.
V Recomhined as CCF3II-SC7-FG23-«-26.
103
-------
and several groups of fractions
that appeared to contain very little
organic matter or low levels of
essentially the same components
were recombined, as indicated in
Table 3, prior to attempting to
identify individual compounds.
CAE3II, the carbon alcohol
extract from well no. 3, was
separated into fractions of less
complexity by classical solubility
separation procedures (11, 12).
A 1.5-ml aliquot of the concentrated
CAE (total volume 4 ml) was dissolved
in 30 ml of diethyl ether, filtered,
and extracted successively with
water, dilute hydrochloric acid,
and dilute sodium hydroxide, as
shown in Figure 7. Five fractions,
namely ether insolubles, water
solubles, bases, acids, and neutrals,
were obtained.
The ether insolubles fraction
contained an appreciable quantity
of material (0.3 g), whereas the
water solubles fraction was of
lesser, but still significant,
weight (0.05 g). However, because
of the polarity and probable
complexity of these fractions and
time limitations on this
investigation, no further studies
of the ether insolubles and water
solubles were conducted.
The bases, acids, and neutrals
fractions were dried on anhydrous
sodium sulfate columns and
concentrated to 1 to 2 ml each in
rotary evaporators. Examination
of these fractions by gas
chromatography indicated that the
acids fraction, designated CAE3II
Acids, contained a total quantity
of organic compounds several orders
of magnitude greater than that
present in the other fractions.
Hence, the acids fraction was
selected for further study.
Identification of Compounds in the
1.5 ml CAE3II
£.<
Ll
CCE and CAE from the Landfill Well
The various fractions obtained
by silica gel column chromatography
of CCE3II and the acids fraction
obtained by solubility separation
of CAE3II were analyzed by combined
Dissolve in
30 ml Dlethyl
Ether, Filter
•;ther Solution
Extract 3X
w/ 10 ml H2°
Residue
Ether Insolubles
Ether Layer
Extract 3X
w/ 10 ml 5Z
HC1
H;0 layer
Water Solubles
Layer
Extract 3X
10 ml 5Z NoOH
IX w/ 10 ml H20
l?0 Layer
Make basic
(pH>10)
Extract 3X
w/ 10 ml Ether
ther
Neutr*
•SXUE H_2°L
Is
Layer
Acidify (pH
-------
mass spectra at the National
Institutes of Health, Bethesda,
Maryland, and Battelle Memorial
Institute, Columbus, Ohio (13),
Additional corroborative evidence
for the structures of compounds
identified on the basis of their
spectra was obtained by direct
comparison with standard compounds
whenever such standards were
available,, When possible, the
quantities of the identified
compounds in the various fractions
were estimated by comparing their
peak heights produced by known
quantities of standard compounds
chronatographed under identical
conditions. These data were then
used to calculate estimated
concentrations of the identified
organic compounds in the sampled
groundwater.
Table 4 presents a tabulation
of those compounds which were
identified in the carbon chloroform
and carbon alcohol extracts prepared
from groundwater from well no. 3.
The CCE and/or CAE fraction(s) in
which the compound was identified
and additional pertinent data such
as industrial uses and toxicity
information are presented for each
compound. Also, estimates of the
quantities present in the sampled
water are given for those compounds
for which quantitative evaluations
were achieved. The general
structures of all the compounds
listed in Table 4 were established
beyond reasonable doubt. However,
it should be noted that exact
positions of substituent attachment
and chain branching were not achieved
for a few compounds, such as the
two C3 alkylbenzenes in CCE3II-SG7-
SG9 and come of the C7, C8f and
C. isomeric acids, because of
unavailability of required standards
or failure of GC columns to separate
closely related compounds.
There was strong evidence for
the presence in the various fractions
of several compounds in addition
to those listed in Table 4, but
their structures were not considered
sufficiently confirmed for inclusion
in this Table. These "possible"
compounds and the fractions in which
they were found were: a C8 ketone,
CCE3II-SG6; a glycol ether, CCE3II-
SG7-SG12; triethyleneglycol ether
and a diester of adipic acid, CCE3II-
SG7-SG13; and benzoic and nonanoic
acids, CAE3II Acids. Also, gas
chromatography of a small aliquot
of the CAE3II Acids fraction after
it was reacted with 141 boron
trifluoride in methanol to esterify
carboxylic acids (14) indicated
the presence of relatively low
quantities of C1?, C^, C16, and
G!, fatty acids in this fraction.
This was not confirmed by mass
spectrometry, however, due to time
limitations.
DISCUSSION
The data presented in Table
4 clearly show that low levels of
many potentially undersirable organic
compounds were being contributed
to groundwater within and immediately
under the Norman landfill by solid
waste deposited in this landfill.
A few of the compounds
identified in this study could be
leachates of natural products,
including foods, or possibly end
products of microbial metabolism.
For example: the short chain,
normal carboxylic acids are
constituents of many foods and
plants; acetic and butyric acids
are common end products of anaerobic
metabolism of carbohydrates; and,
phenolic substances are ubiquitous
phytochemicals. However, most of
the identified compounds are
chemicals commonly employed in
industrial operations (Table 4)
and, therefore, usually associated
with industrial waste. Since
available information indicates
that the Norman landfill has never
received appreciable quantities
of solid waste from industrial
operations, there is an obvious
question concerning the source of
the industrial organic chemicals
leached from this landfill. It
should be noted, however, that most
of the compounds listed in Table
4 are used in the manufacture of
105
-------
Table 4. COMPOUNDS IDENTIFIED IN GROUNDWATER FROM LANDFILL WELL
Eitl»»"d
Compound concentration.
Fenchone 0.2
Ca»phor °'9
Diethyl phthalaie *•!
2,6-Pi-t-««ylbenzoquinone
Butycarbobuloxymethyl phthilate
Dioctyl phthalate" 2,4
g-Cresol M.6
o'Xylene 0.6
g-Xylen* D.9
Cyclohfcxanol 1. 0
N-Ethy l-£-toluen«sulfonaiside 0. it
Diacetone alcohol 10.9
Buroxyethancl
Tri-n-butyl phosphate 1.7
£- Toluene s ulfonanide
Methylpyridinfl
N.N'dlethylforinanide
Acetic acid
Isobutyric *ctd 18. 7
Butyric acid i.s
Isovaleric acid o. 7
Valeric acid 1.1
2-Ethylhexanoic acid 4.2
IsoBoric C6 acid" 17. If
Isonerlc C6 *cid" 0,2?
Iiomeric €7 icid" 7,5V
Isoioric C8 acid*
Caprylic acid 0.6
Caproic acid 1.1
H«pt»noic acid l.Q
CCE and/or CAE
fractionCi)
CCE3II-SG4
CCE3II-SG^
CCE3II-SG4
CCE3II-SG4
CCE3II-SG4
CCE3II-SG4 and
CCE3n-SCT-SG4»6
CCE3II'SC»
CCE3II'SG4
CCE3II-SG4
CCE3II-SG4
CCE311-SG4
CCE3II-SCS and
CCE311 acids
CCE3II-SG7-SC7
CCEJII-5G7-SG7
CCE3I1-SG7-SG7
CCE3II-SC7-SG8
CCEJII-SG7-SGS
CCEMI-SG7-SG9*!!
CCEill-SGT-SGg'll
CCE3H-SG7-SG9-11
CCE3II-SG7-SCO-*!!
CCE3II-SC7-SG9+11
CCE3II-SG7-SG12
CCE5I1-SG7-SG1Z
CCE3I1-SG7-SC1Z
CCE3II-SC7-SG1Z
CCE3JI-SC7-SC21
CCE3II-SG7-SG21
CAE 3 II acids
CA£3I1 acids
CAE3II acids
CAE3II acids
CAE3II acid«
CAI-3II acid*
CAE3II aiid»
CAE3I! acid»
CAB3II acids
CAE3II acids
CAE3II acida
CAE3II acids
CAE3II acids
CAE3I! »cids
•Canorai »tructur« confirmed beyond r«**onitle ioubt. but petition of
necessary standards were unavailable or conpoundi Mara not saparated
tDeUnnlned as N ,N-dimethyi-£- toluflnesulConauld*.
and atldew jirflvanttve, fl.vorinj.15 Ne<»pl»it.ic
Polyaeriiation catalyst,15
Plasticizer, solvent for cellulose acetate, camphor
substitute, p«Tfu»« fixitive, wetting agent.1*
IS
pUjticizer.15
Pl.sticizer.15
1 i IS
d
other polymers. *S
vinyl.. I*
ately toxic..**
crarely toxic-5
Manufacture of phenolic insecticides, lacquer
Plasticiier. Moderately to*icJ5
American petroleum.1*
and enamels.**
Carcinogenic. 17
synthesis .
Insecticide manufacture, dyei, rubber, production of
X P 16
Highly toxic. 1'
A dlaerization product of propylene glycol, a non-
•nd photograpMc cheaicals ; oil well acidizing and'
food additive.1'
See Z-e.thylacxa.nQic acid u»ti above.
I i id* f i i bi i f id
clewing »oapi.1
duct ion.1*
Manufacture of esters for artificial flavors, hexyl-
by C.C. colu»n» eaployed.
-------
a wide array of finished products
for domestic and commercial use
that ultimately will find their
way into most landfills. For
example: the phthalic acid esters
are used very extensively for
production of polymers employed
in such diverse products as food
wrap film, garden hose, upholstery,
electrical insulation, and clothing.
The decomposition and/or leaching
of such manufactured products
deposited in the Norman landfill
would appear most likely to account
for the introduction of industrial
organic pollutants into groundwater
in and near this landfill, even
though it had received essentially
no industrial solid waste, per se.
Those compounds for which
quantitative data were obtained
during this investigation appeared
to be present in groundwater from
well no. 3, the landfill well, only
in low concentrations. However,
the quantitative data resulting
from this work must be considered
as minimum values because of
quantitative inadequacies of the
procedures used, particularly the
carbon adsorption method. These
inadequacies result principally
because: activated carbon may fail
to quantitatively adsorb dissolved
organic compounds from sampled
water; complete recovery of adsorbed
compounds from the activated carbon
may not be accomplished during
extraction; and, volatile sample
components may be lost during drying
of the activiated carbon and
evaporation of extracting solvents.
This is illustrated by comparing
the total combined weight of the
landfill well CCE and CAE, 2.013
mg/l, with the average total organic
carbon content of 13.4 mg/l of water
from this well. If the organic
equivalent of 13.4 mg carbon/1 is
considered, it becomes apparent
that less than 10% of the organic
matter present in the sampled
groundwater was recovered in the
combined CCE and CAE.
The history of the Norman
landfill and dates of newspapers
recovered from well no. 3 during
drilling indicated that the refuse
in the area of the fill near this
well had been in place at least
3 yr at the time this investigation
was conducted. Based on this
information, as well as the
relatively low concentration of
organic carbon (13.4 mg/l) in
groundwater from well no. 3, it
appears likely that most of the
readily leachable organic matter
had already been removed from refuse
near the test when sampling of
groundwater for organic pollutants
was accomplished. It is probable,
therefore, that most of the compounds
identified in this study are
substances that were leached very
slowly from the refuse in the
landfill and/or substances that
persisted for considerable periods
of time in the aquifer in the
vicinity of the refuse from which
they were leached because of sorption
on the earth solids comprising the
aquifer. This observation implies
the potential for long-term insidious
pollution of groundwater by
undesirable organic chemicals from
landfills. Slowly decaying domestic
and commercial products in landfills
would appear likely to serve as
reservoirs feeding low levels of
industrial organic pollutants into
aquifers for many years after the
landfills have been closed and
forgotten. Even those substances
that are sorbed relatively strongly
on aquifer solids could ultimately
pose a pollution threat if they
were resistant to biochemical and
abiotic degradation in the
groundwater environment. Such
compounds could move as zones by
slow, "chromatographic" migration
to finally reach wells providing
water for consumption by humans
or domestic animals. Because of
the low levels of pollutants likely
to be involved, physical properties
of the polluted groundwater would
probably not be altered sufficiently
to indicate the presence of the
offending compounds. This presence
could be a matter of considerable
concern, however, since the health
effects of chronic ingestion through
water of even very low levels of
compounds such as those identified
in this study are largely unknown.
This, coupled with the great
107
-------
difficulty involved in removing
pollutants, particularly those which
tend to adsorb significantly on
aquifer solids, from a polluted
aquifer, dictates the need for
further investigation of this
potential problem. In particular,
information concerning the mobility
and longevity in the groundwater
environment of compounds such as
those in Table 4 are needed. A
limited and less rigorous study
of organic compounds in groundwater
from well No. 2, outside the landfill
(Figure 1), indicated the probable
presence of the same phthalic acid
esters as those identified in
groundwater from well No. 3, thus
suggesting that these compounds
were moving through the aquifer
(21). In general, however,
information of this type is very
scarce.
In assessing the results of
this investigation, it should be
clearly noted that the compounds
identified included only substances
readily amenable to gas
chromatography and represented
probably less than 101 of the
combined weights of the carbon
chloroform and alcohol extracts.
Most of the missing material was
probably composed of compounds too
polar and/or too high in molecular
weight to yield readily to gas
chromatography procedures.
Characterization of this material
would undoubtedly have yielded much
additional information concerning
the organic pollutants contributed
to groundwater by the Norman
landfill, but the necessary
analytical effort for such
characterization during this study
was precluded by time limitations.
CONCLUSIONS
On the basis of information
developed by this investigation,
several conclusions may be proposed,
as noted below.
1. Landfills in which refuse
is deposited in or near
the water table are likely
to contribute many
undesirable organic
chemicals to groundwater
in their proximity.
Even those landfills that
do not receive appreciable
quantities of solid wastes
from industrial operations
may pollute groundwaters
with industrial organic
compounds, probably by
leaching of such substances
from finished products
manufactured for domestic
and commercial use that
ultimately are deposited
in landfills.
The potential exists for
long-term pollution of
groundwater by industrial
organic chemicals from
landfills in contact with
the water table* Such
pollution could persist
for many years after closing
of landfills because of:
slow leaching of organic
compounds from discarded
manufactured products that
serve as reservoirs of
these compounds; and/or
slow "chromatographic"
movement of adsorbed,
intractable compounds away
from the landfill site.
The potential for long-
term, perhaps insidious,
pollution of groundwater
by industrial organic
chemicals from landfills
emphasizes the need for
information concerning
the health effects of long-
term ingestion of water
containing low levels of
such compounds.
Additional information
concerning the generation
and/or release of organic
compounds from refuse,
the persistence of such
compounds in saturated
and unsaturated subsurface
environments, and the
mobility of recalcitrant
108
-------
organic compounds in
groundwater aquifers, as
well as health effects
data, is needed for
realistic evaluation of
the problem of groundwater
pollution by organic
compounds leached from
landfills.
REFERENCES
1. Miller, D. W., F. A. De Luca,
and T. L. Tessier. Ground
Water Contamination in the
Northeastern States. U. S.
Environmental Protection Agency,
Washington, D. C. Report
Number EPA-660/2-74-056. June
1974. p. 211-216. 10.
2. Walker, W. II. Illinois Ground
Water Pollution. J. Amer.
Water Works Assn. 61:31, 1969.
3. Anderson, J. R. , and J. N.
Dornbush. Influence of Sanitary
Landfill on Ground Water 11.
Quality. J. Amer. Water Works
Assn. 59:457-470, 1967.
4. Fuhriman, D. K., and J. R.
Barton. Ground Water Pollution
in Arizona, California, Nevada,
and Utah. U. S. Environmental
Protection Agency, Washington, 12.
U. C. Report Number 16060
ERU 12/71. December 1971.
p. 92-94.
5. Scalf, M. R., J. W. Keeley,
and C. J. LaFevers. Ground
Mater Pollution in the South
Central States. U. S.
Environmental Protection Agency,
Corvallis, OR. Report Number
EPA-R2-73-268. June 1973.
p. 100-102.
6. Sanitary Landfill Studies, 13,
Appendix A: Summary of Selected
Previous Investigations.
California State Department
of Natural Resources,
Sacramento, CA. Bulletin
Number 147-5. July 1969.
7. Hughes, fi. M. R. A. Landon,
and R. V,'. Farvolden. Hydrology 14
of Solid Waste Disposal Sites
in Northeastern Illinois.
Illinois State Geological
Survey, Environmental Geology
Notes, Urbana, II. Publication
Number 45. April 1971. 25 p.
Garbutt, G.H. Report of the
Preliminary Study of a Landfill
in McClain County, Oklahoma.
University of Oklahoma.
(Unpublished special project
report. Norman, OK. June
1972.) 16 p.
Breidenbach, A. W., J. J.
Lichtenberg, C. G. Henke, D.
J. Smith, J. W. Eichelberg,
Jr., and H. Stierle. The
Identification and Measurement
of Chlorinated Hydrocarbon
Pesticides in Surface Waters.
U. S. Department of the
Interior, Federal Water
Pollution Control
Administration, Washington,
D. C. 1966. p. 44-50.
Booth, R. L., J. N. English,
and G. N. McDermott. Evaluation
of Sampling Conditions in the
Carbon Adsorption Method.
J. Amer. Water Works Assn.
57:215-220, 1965.
Shriner, R. L., R. C. Fuson,
and D. Y. Curtin. The
Systematic Identification of
Organic Compounds, Fifth
Edition. New York, NY. John
Wiley and Sons, Inc., 1965.
p. 67-107.
Breidenbach, A. W., J. J.
Lichtenberg, C. F. Henke, D.
J. Smith, J. W. Eichelberger,
Jr., and II. Stierle. The
Identification and Measurement
of Chlorinated Hydrocarbon
Pesticides in Surface Waters.
U. S. Department of the
Interior, Federal Water
Pollution Control
Administration, Washington,
D. C. 1966. p. 12-14.
Webb, R. G., A. W. Garrison,
L. H. Keith, and J. H. McGuire.
Current Practice in GC-MS
Analysis of Organics in Water.
Environmental Protection Agency,
Corvallis, OR. Report Number
EPA-R2-73-277. 1973. p. 37-
41.
Metcalfe, L. D., and A. A.
Schmitz. The Rapid Preparation
of Fatty Acid Esters for Gas
Chromatographic Analysis.
Anal. Chem. 33:363-364, 1961.
109
-------
15. Hawley, G. G. , Ed. The
Condensed Chemical Dictionary,
Eighth Edition. New York,
NY. Van Nostrand Reinhold
Co., 1971, 971 p.
16. Webb, R. G., A. W. Garrison,
L. II. Keith, and J. H. McGuire.
Current Practice in GC-MS
Analysis of Organics in Water.
U. S. Environmental Protection
Agency, Corvallis, OR. Report
Number EPA-R2-73.-277. 1973.
p. 62-87.
17. Christenson, II. E., Ed. The
Toxic Substances List. U.S.
Department of Health, Education,
Welfare. National Institute
for Occupational Safety and
Health, Rockville, HD.
Publication Number HSM 72-
10265. June 1972. 563 p.
18. Stecher, P. G. The Merck
Index. Rahway, NJ. Merck
and Co. Inc., 1968. 1713 p.
19. Stahl, W. H., Ed. Compilation
of Odor and Taste Threshold
Values Data. American Society
for Testing and Materials,
Philadelphia, PA. 1973.
20. Mark, H. F., Ed. Encyclopedia
of Chemical Technology. New
York, NY. John Wiley and Sons,
Inc., 1970. Vol. 8. p. 849-
850.
21. Robertson, J. M., C. R.
Toussaint, and M. A. Jerque.
Organic Compounds Entering
Ground Water From a Landfill,
U. S. Environmental Protection
Agency, Washington, D. C.
Report Number EPA-660/2-74-
077. September 1974. p. 23-24,
110
-------
ATTENUATION MECHANISMS OF POLLUTANTS THROUGH SOILS
Wallace H. Fuller
and
Nic Korte
College of Agriculture
University of Arizona
Tucson, Arizona
INTRODUCTION
The title implies far more
than we or anyone can deliver in
the short time allotted to the
subject at this symposium. Despite
the complicated and interrelated
subject of attenuation in soils,
we believe that, from the great
volume of material, something can
be extracted and refined that can
be useful as a basis for disposal-
site selection and management.
As a necessary beginning, the
meaning of two words, attenuation
and mechanism, requires some
explaining to develop common ground
for their use in this discussion.
Attenuation
Attenuation is defined here
by looking at the movement of a
pulse of a solute through a soil.
As the pulse migrates, the maximum
concentration decreases. Attenuation
can then be defined as the decrease
of the maximum concentration for
some fixed time or distance traveled.
Mechanisms
The word mechanism cannot be
defined precisely.Two choices
in the latest edition of Webster's
Dictionary are "A system whose parts
work together like those of a
machine," or "any system or means
for doing something." What most
often are described as "mechanisms"
by the various pollution control
communication media are, in reality,
a series of ill-defined processes
that relate to or correlate with
some measurable parameter of the
microhabitat of those reactions.
For example, Eh (red/ox) has been
called a mechanism. Red/ox, though,
is not a mechanism by which soils
retain trace elements of leachates
or other wastewaters. Red/ox
potential of a soil habitat, however,
can be significantly related to
a host of electron transfers among
elements that influence their
solubility in the displacing soil
solution. Mechanism as used here
will relate to the more specific
chemical reactions that can be
identified.
*Contribution from The University of Arizona Agricultural Experiment Station,
Dept. of Soils, Water and Engineering, Tucson 85721. Journal Series Paper
No. 2409.
Ill
-------
For a lack of better
terminology, the phrase "factor(s)
of attenuation" will be used in
identifying broad classes of
reactions that appear to control
migration rates. They may be grouped
because of trends in a pollutant's
solubility, which is controlled
by an identifiable chemical or
physical condition and which has
a standard means of measurement.
For example, pH value may be expected
to initiate or limit the solubility
of certain substances through [H] +
and [OH]' activity levels. The
pH values of a solution or suspension
habitat can be readily monitored
by a pH meter.
A definition of the term "trace
element(s)" also will help clarify
this communication. The term is
used here to identify those selected,
potentially hazardous pollutants
(As, Be, Cd, Cr, Cu, Ni, Hg, Pb,
Se, V, and Zn) and other elements
that nay be found in biological
tissues or cells in amounts usually
considered to be trace as opposed
to the more macro-levels of N, P,
K, H, 0, C, Ca, Na, etc.
Microhabitat of the Soil
Before discussing specific
reactions influencing mobility and
immobility of trace elements in
soils, it may be well to review
some of the broad alterable factors
of the soil habitat that can affect
trace-element mobility. Disposal
sites of wastes usually are located
in subsurface soils, sand and gravel
excavations, geologic materials,
and shrouded in disturbed soils.
The waste is left to sour in the
bowels of anaerobosis. Thus,
disposal management must consider
the unusual soil condition.
Leachates, themselves, also will
alter the natural soil environment.
Some important characteristics
of the nicrohabitat of the soil
that may be altered and, in turn,
may alter trace-element movement,
as it might occur in the usual
aerated soil, are:
4.
5.
8.
aeration (anoxic,
waterlogged, swampy,
reducing conditions, etc.)
particle size distribution,
texture, or clay content
permeability or pore size
distribution as it nay
influence flux of the soil
solution
pH values (either high
degreeoT acidity or
alkalinity may develop
from waste disposal and
acid status of leachate
and waste streams may
influence the solubility
of complexes of potential
pollutants)
lime (free soil lime,
caliche, agricultural
limestone, and commercial
limes)
iron, aluminum, and man-
ganese hydroxy oxides in
unusually high concen-
tration or state of
reactivity or solubility
organic matter and organic
soils (.sequestering ot
heavy metals with organic
complexes alters solubility
and mobility as chelates
and certain chemical unions
can form immobile organo-
metallic complexes)
high specific salt concen-
trations, where trace
element reactions become
salt dependent.
This brief listing over
simplifies the factors in the
microhabitat that influence trace
element mobility in disposal-site
soils. For example, organic matter
can attenuate heavy metals by
combining with them to form very
slowly soluble complexes or increase
their mobility by forming highly
soluble organo-metal-ion complexes,
which differ greatly in degree of
112
-------
attenuation. Nevertheless, it is
well to make a beginning in a very
general way, recognizing that this
approach is necessary for practical
problem solving.
ATTENUATION AS REVEALED
BY SOIL RESEARCH
First let us define the system
and habitat that concerns us in
the soil trace element attenuation
program. The system is a municipal
solid-waste, sanitary-landfill
leachate generator. The habitat
is an anaerobic fermentation process
that accumulates aqueous acid
leachate containing various levels
of potentially hazardous trace-
element pollutants. The amount
of leachate generated depends on
the disposal site rainfall pattern.
The concentration of trace element
appearing in the leachate depends
on the kind of industry dumping
into the municipal landfill. The
soil habitat also is anaerobic in
the landfill where leachate collects.
Experimental Procedures at The
University of Arizona
A 1000-gal leachate generator
was constructed, packed with
representative municipal refuse,
filled to brimming with water, and
allowed to ferment for 6 warm-season
months. The leachate was drawn
off under high C02 pressure in
absence of atmospheric 02 and
displaced through 10 soils from
7 major orders (Table 1), again
in the absence of atmospheric 02
and in the presence of C02 .
The soil columns were cylinders
measuring 10 x 22 cm and S x 10
cm, packed to known densities.
Water, natural leachate, and trace-
element "spiked" leachate were
passed through the soil. The
effluent was collected in increments
of 0.5 and 1.0 pore-space volumes
(depending on column size) in a
24-hr period under C02 in the
exclusion of atmospheric 02 . The
concentration of certain elements
in the influent and effluent was
monitored and data were collected.
Table 1. CHARACTERISTICS OF THE SOILS USED
soil
series
Anthony
Ava
Chalmers
Davidson
Fanno
Kalkaska
Mohave
,,'ohave
Holokal
Nicholson
Waaram
Cation Elec.
exch. cond. of
Foil capac. extract,
order pH meq/100 g umhos/cm
Entisol 7.B 6 328
Alfisol 4.5 19 157
Mollisol 6.6 26 288
Ultisol 6.2 9 169
Alfisol 7.0 33 392
Fnodosol 4.7 10 237
Aridiuol 7.3 10 615
Aridisol 7.8 12 510
nxisol 6.2 14 1262
Alfisol 6.7 37 176
Ultisol «,2 2,1 225
Column
bulX
density, Sand, Silt, Clay, Texture
rj/cm' J J t class
2.07 71 14 IS Sandv
loam
1.45 10 60 31 Siltv
clav
loam
1.60 7 58 35 Filtv
clav
loam
1.89 19 20 61 Clav
1.48 35 19 46 Clav
1.53 91 4 5 Rand
1.78 52 37 11 Sandy
loam
1.54 32 28 40 Silty
clay
loan*
1.44 23 25 52 Clav
1.53 3 47 49 Silty
clay
1.89 88 8 4 Loamy
sand
Predominant
clav
Montmorillonite,
mica
Vermiculite,
kaolinite
Montmori 1 lonite ,
vermiculite
Kaolinite
^ontmorillonite.
mica
Chlorite,
fcsolinite
Mica, kaolinite
Mica ,
montmorillonite
Kaolinite,
aihbsite
Vermiculite
Kaolinite,
chlorite
*Tjlatcd in orfl«r of importance.
113
-------
The data reported here were
collected from experiments (1) where
columns were leached with a landfill
leachate individually spiked with
selected potentially hazardous
elements (As, Be, Ce, Cr, Cu, Hg,
Ni, Pb, Se, V, and Zn). In each
instance, the leachate was acidified
to pll 5.0 with HC1 and spiked with
70 to 120 ppm of the element of
interest. The leachate was passed
through soil columns (5-x 10-cm)
and adjusted to maintain a steady
solution flux of one pore-space
displacement in 24 hr. The leaching
was continued until (a) breakthrough
(effluent concentration = influent
concentration), (b) steady state,
or (c) continued absence of the
element in the effluent. In all
cases, the columns were cut into
1-cm segments and the element
extracted by IlaO and dilute HC1.
Classification of Factors in
Attenuation
Faced with a paucity of critical
soils research data, speculation
dominates both the literature and
our thinking concerning the levels
of importance of the biological,
physical, and chemical factors
influencing attenuation in soils
of trace elements in landfill
leachates. It seems necessary,
therefore, to divide this soils
presentation into at least three
parts to distinguish among those
factors that have received (a)
research attention as being important
in attenuation, (b) research
attention as being unimportant in
attenuation, and (cj little or no
research attention as to their
importance in attenuation. These
groupings find reality in unpublished
Table 2. TOTAL ANALYSIS OF SOILS FOR TRACE METALS AND FREE IRON OXIDES
Soil
Anthony
Ava
Chalmers
Davidson
Fanno
Kalkaska
Mohave
Molokai
Nicholson
Wagram
Mn,
g/g
275
360
330
4100
280
80
825
7400
950
50
Co,
g/g
50
50
60
120
45
25
50
310
50
--
Zn,
g/g
55
77
100
110
70
45
85
320
130
40
Ni,
g/g
80
110
130
120
100
50
100
600
135
80
Cu,
g/g
200
80
83
160
60
46
265
260
65
62
Cr,
g/g
25
55
68
90
38
15
18
410
68
--
Fe
oxides,
%
1.8
4.0
3.1
17.0
3.7
1,8
1.7
23.0
5.6
0.6
114
-------
100
80
60
§ 40
20
10
figure 1. Percent of chromium VI adsorbed by 10 cm of soil after 14 pore-
space displacements. 1, Anthony; 2, Ava; 3, Davidson; 4, Fanno;
5, Kalkaska; 6, Mohave; 7, Mohave(Ca); 8, Molokai; 9, Nicholson;
and 10, Wagram.
TOO
80
60
3 40
20
10
Figure 2. Percent of arsenic adsorbed by 10 cm of soil after nine pore-
space displacements. 1, Anthony; 2, Ava; 3, Davidson; 4, Fanno,
5, Kalkaska; 6, Mohave; 7, Mohave(Ca); 8, Molokai; 9, Nicholson;
and 10, Wagram.
IIS
-------
Q
LU
8
O
100,
80
60
40
20
Figure 3. Percentage of cadmium adsorbed by 10 cm of soil after 1.05 pore-
space displacements. 1, Anthony; 2, Ava; 3, Davidson; 4, Fanno;
5, Kalkaska; 6, Mohave; 7, Mohave(Ca); 8, Molokai; 9, Nicholson;
and 10, Wagram.
data similar to those respresented
in Tables 1 and 2 and Figures 1,
2 and 3. By comparing the soil
parameters reported in Tables 1
and 2 with the migration of the
elements depicted in Table 3 and
the three figures, certain soil
characteristics stand out more
clearly as factors of attenuation
than others.
The figures show that particle
size distribution (texture) plays
the dominant role in attenuation
with the partial exception of
chromium (Figure i) where pH is
also important, in general, those
soils highest in clay-sized particles
and free iron oxides (Molokai,
Davidson, and Nicholson) are found
to attenuate the trace elements
to the greatest extent (Figures
2 and 3). Mohave is high in lime
and as such is also highly effective
in immobilizing trace elements.
The negative effect of pH on chromium
migration is illustrated in Figure
1 by chromium's mobility in Mohave.
The usual behavior for this soil
is displayed in Figures 2 and 3.
Important Factors in Attenuation
Those factors found to be the
most important in attenuation in
soils by the research reported in
Table 3 and Figures 1,2, and 3
are:
1. size of the soil particles
(or total clay content)
2. free "iron oxide" content
of the soil (other hydrous
oxides have yet to be
confirmed)
3. soil pH value, and
4. solution flux through soil.
Size of the sjul particle:
Particle-size distribution was
highly variable in the 10 soils
studies, ranging from sand to clay
(Table 1). In fact, it was believed
116
-------
Table 3. THE PORE VOLUME IN WHICH THE ELEMENT FIRST APPEARED IN THE
SOIL-COLUMN EFFLUENT
pH
As
Be
Cd
Cr
Cu
Pb
Se
An
Hg
Wagram
Ava
Kalkaska
Davidson
Molokai
Nicholson
Fanno
Mohave
Mohave ca
Anthony
4.
4.
4.
6.
6.
6.
7.
7.
7.
7.
2
5
7
2
2
7
0
3
8
8
1
5
1
13
13
12
1
1
10
1
1
3
4
6
12
5
4
13
6
5
1
1
2
3
30
13
14
13
8
2
1
7
1
17
19
5
1
1
1
1
20*
1
19
27
13
12
15
19
15
15
1
10
17
26
22
16
16
16
23
17
4
21
10
17
14
8
3
2
6
2
1
1
1
5
27
7
13
17
11
2
1
1
1
1
7
1
4
5
6
1
*Indicates that none of the elements appeared in the effluent for
the listed number of pore volumes.
early in the research program that
soil texture was so highly variable
it would dominate to the exclusion
of the other soil parameters. This
was not the case. Although when
the data was subjected to statistical
analyses, a positive correlation
between percentage of the element
adsorbed and total clay content,
and a negative correlation to sand
were shown. Not all correlation
coefficients, however, were found
to be significant, since some other
factors contribute to attenuation
and/or element mobility.
Hydrous oxides: In general,
tne most significant correlations
occurred between percentage trace
element retained and "free iron
oxide" as determined in the soil
by the method of Kilmer (4). The
Davidson and Molokai soils are
highest in extractable free iron
oxide (Table 2). These soils
attenuate most trace elements more
strongly than other soils (Table
3). The correlation between free
iron oxide and total soil Mn is
highly significant. Thus, total
Mn also is closely correlated with
trace element migration. The
importance of total Mn, at first
analyses appears to be less
significant than free iron oxide.
These practical soil research
findings agree with the pure-system
chemical research of Jenne (3) and
Gadde and Laitinen (2).
Soil pH Value; Although pH
value is one of the most important
factors in attenuation, it is less
significant than the first two
factors. Using ground agricultural
limestone from Kentucky in soil
columns, the presence of a thin
layer of lime slowed the migration
rate of Cd and Ni (Tables 4 and
5, respectively). The lime effect
is considered to be pH dominated
in these instances. Considering
total attenuation or percentage
adsorption, the effect of lime is
the least important for As, Cr,
and Se (Tables 3 and 6).
117
-------
Table 4. THE EFFECT OF LIME ON
ATTENUATION OF Cd IN
WAGRAM SOIL*
Table 5. THE EFFECT OF LIME ON
ATTENUATION OF Ni IN
WAGRAM SOIL*
Pore-space
displacements
1
2
3
4
5
6
7
8
10
11
13
15
23
Soil alone,
ppm
15
42
46
47
37
42
56
62
75
80
86
100
V «
2 cm of
lime ppm
0
0
0
0
0
0
0
0
0
0
0
T
14
Pore-space
displacements
0.8
2.0
4.0
10.0
Soil + 2 cm
limestone ,
ppm
1.5
9.0
48.0
66.0
Soil
alone,
ppm
65
90
__
100
*Each column held 10 cm (depth) of
Wagram soil; Ni in leachate
» lOOppm.
*10-cm depth of Wagram soil; Cd in
leachate =100ppm.
Table 6. THE EFFECT OF LIME AND HYDROUS OXIDES OF IRON ON ATTENUATION
OF Cr IN WAGRAM AND ANTHONY SOILS
Pore-space
displacements
0.5
1.0
1.5
2.0
3.0
4.0
4.5
Soil
alone,
ppm
36
_,
72
75
_ _
75
Anthony
2 cm
lime,
ppm
34
75
73
— —
75
Fe oxide
added,
ppm
1.8
2.0
7.5
24.0
Soil
alone ,
ppm
4
_ .
25
35
75
__
--
Wagram
2 cm
lime,
ppm
10
_.
30
45
78
__
..
Fe oxide
added,
ppm
0.3
--
0.35
1.0
5.0
_ _
--
*The columns held 10 cm depth of the two soils; Cr in leachate=75ppm.
These are the only selected trace
elements that appear as anions in
aqueous solutions. The relationships
of pH to attenuations, which were
found, may be summarized briefly:
1. Se and Cr show negative
correlation to pH. All
other trace elements are
positively correlated.
(See Tables 3 and 6).
Movement of Se and Cr
relate more strongly to
the soil hydrous oxide
content than any other
elements (Figure 1 and
Table 2).
The initial appearance
of the trace element in
the solution displacements
for soils with alkaline
118
-------
pH values is slower than
those low in pH values
(Table 3) except for Cr
and Se and maybe As (Figure
1 and 2).
4. Hg shows no strong trend
to differences found at
normal soil pll values
(Table 3). Mercury migrated
more rapidly when associated
as an inorganic ion in
water than when associated
with landfill leachate
(Figure 4). The presence
of organic substances in
the leachate appears to
enhance Hg movement since
concentration of other
constiuents was very low.
Soil solution flux; Solution
flux Tsone of the most important
physical factors in attenuation
in landfill leachate and wastewater
disposal. The attenuation of trace
elements in natural systems may
occur during any number of possible
flow regimes. By studying flux,
we can describe migration under
realistic field conditions. It
provides another mechanism of control
by which attenuation may be
maximized. The soil parameter that
most closely relates to flux is
clay content. The importance of
solution flux appears repeatedly
in the research, and at times is
expressed in the literature (6),
yet specific data only now are being
generated at quantitative levels
(1). The movement of Fe and Al,
for example, was greatly retarded
by slight changes in density of
Nicholson soil (Table 7).
Factors Considered as Unimportant in
Attenuation
Those factors found to be the
least important in attenuation in
soils by the research at The
University of Arizona are:
1. sand
2. cation exchange capacity, and
3. soil organic matter (except
for Ilg)
100
80
60
g 40
<
20
0 I
ANTHONY
0 I
CHALMERS
0 I
DAVIDSON
FANNO
SOILS
Figure 4. The absorption of mercury (HgCl) spiked into landfill leachate
and water alone at pll 5.0 through four soils after 7.5 pore space
displacements. 0 = Organic-Leachate; I = Inorganic-Water.
119
-------
Sand; Sand is negatively
correlated with attenuation. Those
soils highest in quartz sand are
the least retentive of trace
elements. The influence of particle
size distribution raises the question
of the physical aspect of surface
reaction and total surface area
as a factor in mobility of trace
elements.
Cation exchange capacity;
The cation exchange capacity (CEC)
of the soils usually does not
correlate significantly with trace
element migration. Where CEC does
seem to have some relationship,
percentage clay, percentage FeO,
and pH all provide a better
correlation. CEC appears to be
a transitory mechanism to retain
ions for short periods of time.
Those trace elements attached to
the exchange position are clearly
in a highly migratory state.
Soil organic matter; Soils
having organic carbon compounds
in abundance such as the Spodic
Kalkaska appeared to have little
effect on attenuation except for
Cu and Pb (Table 3). These two
elements, however, were strongly
retained by nearly all soils. The
importance of soil organic matter
in attenuation certainly needs
further careful research; now it
qualifies for a place in the next
section as belonging to a group
of little-evaluated or known
importance. Mercury, however,
appears to be more mobile in Anthony
Chalmers, Davidson, and Fanno when
"spiked" into landfill leachate
where organic constituents are
present than when in water where
no organic matter exists (Figure
4).
Factors of Little Known Importance
Those factors of little known
impact on attenuation appear in
this group because they (a) have
not received enough research
attention to be evaluated, (b) have
not appeared to be sufficiently
dominant as to reveal a clear-cut
effect, (c) appear in a state too
Table 7. A COMPARISON OF IRON AND ALUMINUM ATTENUATION AT TWO SOLUTION
FLOW RATES THROUGH NICHOLSON SOIL*
Pore
space
dis-
placement
0.5
1.0
1.5
2.0
2.5
2.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
Nicholson
Time
of
contact,
days
1
2
3
4
5
6
7
8
9
10
11
12
13
Cumulate
effluent
volume,
ml
330
690
1020
1435
1850
2185
2555
2955
3340
3775
4250
4745
5240
A
Cone
in
Nicholson
•
effluent
Fe,
ppm
0.2
0.2
0.3
12
104
136
230
300
340
500
780
830
830
Al,
ppm
0
0
0
0
2
3
8
10
16
44
125
140
160
Time
of
contact,
days
1
4
6
12
16
21
29
33
37
46
55
60
65
Cumulate
effluent
volume,
ml
340
620
1040
1435
1725
2115
2685
2960
3235
3805
4420
4750
5070
B
Cone
in
•
effluent
Fe,
ppm
0.2
0.4
0.5
2.6
1.6
0.3
0.7
2.2
1.8
1.6
1.1
2.0
110.0
AI7
ppm
0
0
0
0
0
0
0 *
0
0
0
0
0
1.0
*Soil columns were 10 cm diameter x 22 cm long.
slightly greater denisty than column A.
Column B was packed to
120
-------
elusive to be measured quantita-
tively, (d) are truly marginal in
effect, and/or (e) are highly
specific for trace elements not
included in the ones being considered
now. Sonic of the factors that fall
into this class are:
1. kind of clay mineral
2. concentration of total
salts or total dissolved
solids (IDS)
3. specific ion effect and
ion interaction effects
4. biological mineralization
and immobilization
5. reactions with organic
constituents (chelation
and other complexing as
an example)
6. precipitation in a highly
nixed and heterogeneous
medium as soils
7. ion exchange reactions,
and
8. physical reactions involv-
ing pore-size distribution,
surface reactions, physio-
chemical adsorption, time,
and temperature effects.
RELATIVE MOBILITY IN
LANDFILL LEACHATE
Rank of Trace Elements
The relative mobility of 11
trace elements in landfill leachate
through 11 soils representing 7
soil orders nay be oriented as
follows:
1. most generally mobile--
Cr, Hg, Ni
2. least generally mobile--
Pb, Cu
3. mobility varies with
conditions — As, Be, Cd,
Se, V, and Zn.
Rank of Soils
The soil that attenuates most
effectively is Molokai, an Oxisol
from Hawaii (Table 3 and Figures
1, 2, and 3). Davidson, an Ultiso^
from North Carolina, ranks second
in its effectiveness to immobilize
trace elements. Both soils are
high in clay and extractable "free
iron oxides." The Wagram Ultisoj.,
a daolinite, quartz sand (88%),
retains trace elements least
effectively. The other soils vary
but are generally ranked according
to amount of clay-sized particles.
121
-------
ACKNOWLEDGMENT
This research was supported
in part by the U.S. Environmental
Protection Agency, Solid and Hazar-
dous Waste Research Laboratory,
Cincinnati, Ohio, Contract No. 68-
03-0208.
REFERENCES
1. Fuller, W. II., et al., 1975.
"Investigation of leachate
pollutant attenuation in soils,"
Final Report for US EPA Contract
No. 68-03-0208 (in press).
2. Gadde, R. Rao, and Herbert
A. Laitinen, 1974. "Studies
of heavy metal adsorption by
hydrous iron and manganese
oxides", Anal. Chem. 46:2002-
2026.
3. Jenne, E. A., 1968. "Controls
on Mn, Fe, Co, Ni, Cu, and
Zn concentrations in soils
and water: The significant
role of hydrous Mn and Fe
oxides," in "Trace Inorganics
in Water" Advan. Chen, Ser.
73:337-387.
4. Kilmer, V0 J., 1960. "The
estimation of free iron oxides
in soils," Soil Sci. Soc. Am.
Proc. 24:420-421.
5. Korte, Nic, J. Skopp, E. E.
Niebla, and W. H. Fuller, 1975.
"A baseline study on trace
metal elution from diverse
soil types," (Submitted for
publication. In press).
6. Lapidus, L., and N. R. Amundsen,
1952. "Mathematics of adsorption
in beds. VI. The effect of
longitudinal diffusion in ion
exchange and chromatographic
columns," J» Phys. Chem. 56:984-
988.
122
-------
MONITORING TOXIC CHEMICALS IN LAND DISPOSAL SITES*
William II. Walker
Illinois State Water Survey
Urbana, Illinois
INTRODUCTION
Existing air and surface-water
pollution abatement regulations
are forcing an increasing volume
of hazardous chemical waste to be
diverted to the land for ultimate
disposal, particularly in heavily
populated, industrial regions of
the United States. Land disposal
of potentially hazardous chemical,
bacteriological, virological, and
radiological waste is now being
widely employed as being the most
practical and economically feasible
waste disposal means available.
Justification for using the land
for this purpose is based on the
hypothesis that earth materials
have the capability to precipitate,
absorb, exchange, convert, decompose,
or volatilize all kinds of hazardous
material to harmless states.
This form of disposal has
special appeal to municipalities
throughout the country presently
confronted with the dilemma of
upgrading inadequate sewage treatncnt
plants to meet existing Water Quality
Effluent Standards. An increasing
number of air, vegetation, and water
pollution occurrences from such
sources seems to suggest that some
landfills are serving only as partial
or temporary filtration-retention
beds.
Practically all of the municipal
waste treatment systems in the
country recieve, treat, and
eventually discard liquid waste
streams. Most of these waste
treatment plants were designed for
an earlier time when there were
fewer people and when contaminants
were limited to bacteria and uncom-
plicated organic wastes. Water
pollution control is becoming more
complex because of a growing roster
of bacteria, viruses, antibiotics,
hormones, nutrients, weedkillers,
fungicides, pesticides, and trace
metals, and a large number of toxic
chemical compounds. Any of these
pollutants may be contained in
wastewater streams dumped into
municipal sewers.
However, adequate dilution
does not always occur before or
after the waste stream reaches the
treatment plant. Also, treatment
by the older methods generally does
not remove or render harmless all
of the hazardous materials contained
in the waste streams entering the
plant. In fact, some of these
materials arc in a more concentrated
form when they leave the plant in
effluent and sludge than they were
upon entry.
Many of the hazardous wastes
present in treatment plant discharges
are difficult to detect and quan-
titatively evaluate by available
equipment and methods. They are
often not identified by prescribed
waste stream analyses programs.
Their existence in sewage-plant
* Reprint from Pollution Engineering. 6(9):50-53, Sept. 1974, Technical
Publishing Company, 1974.
123
-------
effluent and sludge raay remain
unrevcaled. It is this liquid and
semi-liquid waste material that
is now being dumped on the land.
Hazardous waste pollutants
may be returned to the environment
from land disposal sites by one
or more of six avenues (Figure 1).
ATMOSPHERE
OVERLAND/ 1
RUNOFF \ 1
V^
LAND DISPOSAL SITE
son. V—.
RETENTION
n
REMOVAL
IN CROPS
ORGANIC
RESIDUE
RETENTION
GROUND WATER
RECHARGE
Figure 1. Possible avenues for
pollutants to reentcr
the environment from
toxic waste land
disposal sites.
Some chemical compounds are
volatilized in the soil (for example,
hydrogen sulfide, methane, ammonia
and other nitrogen gases), and these
may enter the atmosphere and be
transported from the disposal area
in gaseous form. Other constituents,
such as phosphate, arsenic, iron,
zinc, chromium, mercury, and lead,
are retained in the soil for varying
lengths of time. Nitrate, chloride,
sulfate, boron, cyanide, and some
pesticides readily pass through
the soil to the groudwater reservoir.
Thus, many of the chemical compounds
commonly discarded on the land may
be taken up by vegetation growing
in the disposal area and returned
to the ecosystem. In fact, the
six dissipation routes shown in
Figure 1 are so interrelated that
pollutants are exchanged from one
to another.
MONITORING THE SITES
An effective monitoring system
for toxic waste disposal areas may
become a routine requirement. Such
a program would provide an evaluation
of immediate and potential long-
term pollution effects, including
total pollutant volumes retained
and those dissipated in each of
the regimes shown in Figure 1,
In practice, most monitoring
facilities are designed to detect
only surface water and groundwater
pollution. Little, if any, attention
is given to possible adverse effects
of banked pollutants reentering
the environment from soil or plant
storage areas. As a result, the
data obtained are often incomplete
and not representative at all of
the total air, plant, soil, and
water pollution that actually may
be originating from such sources.
For example, in the case of
surface water monitoring, little
if any actual measuring of overland
runoff is ever attempted. Even
if measurements are made of this
component, they usually consist
only of periodic water sampling
and analysis without corresponding
volume-of-flow measurements, which
must be collected concurrently if
an accurate quantitative evaluation
of this factor is to be obtained.
The same may be true of field
drainage tile monitoring designed
to detect pollution released from
surface soils and shallow water-
bearing formations. Also, in both
of these cases, the frequency of
water sampling generally is monthly
or bimonthly. Seldom are samples
taken during and immediately
following major precipitation runoff
periods when the major quantity
of toxic chemical removal by these
routes should be expected to occur.
This makes it unlikely that peak
or minimum pollutant concentrations
can be accurately defined.
The monitoring systems
themselves need to be studied and
updated. For instance, in fine-
grained, low permeability earth
materials generally considered to
be most desirable for land disposal
sites, a representative groundwater
sample may not be obtainable from
a properly placed monitoring well
for several weeks or even months
following installation because of
the low water-yielding
124
-------
acteristics of these materials.
Also due to the usual variations
in permeability of
in the zone of saturation
landfill sites, observation wells
in short vertical sections of the
reservoir may not
provide representative sampling
of groundwater flowing through the
various aquifer segments at
given location time.
In existing land disposal
sites, only the lower, permeable
parts of the unconsolidated earth
material bedrock are
by monitoring wells, though
overlying water-bearing zones
known' to be present. Under such
conditions (Figure 2)» a major
portion of groundwater pollution
derived from the disposal sites
flow undetected through
overlying beds to nearby natural
or man-made drainage course.
Figure 2, Groundwater nonitoring
using wells,
A sinilar sif lution can occur in
area-- .mderiatU by only one primary
w,it<'J-bearing ions if too
..tonitorlng wells installed,
or if the wells installed only
the ippermost part of the of
saturation.
Recent studies suggest that
observation of the well monitoring
system nay not be the most effective
to trace chemical pollutant
flow paths or to determine
groundwater chemical concentrations
at any time or depth. Instead,
studies that
analyses of core from
underlying material profile
permit a positive definition of
chenical constituent within
profile at given location.
This' is of whether
chemicals present in
precipitated form in of
aeration, held by retention
on soil particles In
semisaturated fringe, or
dissolved in groundwater within
the of saturation. In addition,
that chemical
analyses of soil core samples usually
prove to be a much faster, easier,
monitoring
method for soil groundwater
pollution evaluation than
analyses of groundwater
collected from observation wells.
Theoretically, detection
of pollution irt of the six
dissipation illustrated
in Figure 1 only two
samples--one collected prior to
the beginning of disposal
operation, at later
a concentration
occurred. However, a
quantitative evaluation of the
buildup of given chemical
constituent requires a much more
elaborate procedure over
a longer of time. For
if pollutant
in vegetation is to be defined,
vegetation at given site
be
application at the
of growing
for as as is used.
In addition, if of the
vegetation is
disposal area, o£ the
portion of
be analyzed representative
of plant residue left in
field. The quantity of pollutant
in water or soil at
given vary considerably
with season, with
of application,
with the total service life of
site. These factors, plus the
possible toxic chemical interchange
the various regimes,
sampling of all of
125
-------
mandatory, perhaps for an extended
period of time after the site has
been abandoned as a waste disposal
site.
SAMPLING POINTS
Accurate evaluation of overall
pollutant buildup, migration
patterns, and flow rates within
and beneath the site and surrounding
area requires several strategically
located stations for samples to
be concurrently collected and
analyzed.
The number of sampling points
required is primarily controlled
by the expected variability of each
parameter and the degree of mon-
the degree of monitoring accuracy
desired. Sampling-point distribution
and monitoring procedures are
dictated by geologic, hydrologic,
and chemical complexities likely
to be encountered. Under ideal
conditions, where the underlying
earth materials are fairly
homogeneous, impermeable, and
uniformly sloping on one direction,
only three sampling points should
be required. These three points
should be equally spaced on a line
through the center of the disposal
area and extending from the area
of highest water table to lowest
elevations on the property. In
such an arrangement, the direction
of groundwater flow and its chemical
concentration change with distance
of travel should be readily
discernible if groundwater flow
is uniform throughout the zone of
saturation. However, earth materials
may not be homogeneous, and the
flow paths of groundwater through
any given profile may be complex.
The upper and basal surfaces and
intervening strata may be warped
in a manner that will influence
the direction of groundwater flow
and resultant horizontal and vertical
migration patterns of toxic chemical
movement. If more than one water-
carrying stratum is present in the
underlying earth material section,
each water-bearing unit may have
to be monitored by properly spaced,
3-station lines.
In systems such as these, the
preferable pattern of sampling
stations from a mathematical
standpoint is a square-grid network
uniformly distributed throughout
the entire disposal area and the
downgradient lands likely to be
adversely affected. The number
and spacing of sampling stations
suggested is illustrated in Figure
3. Within any 10-ft by 10-ft
sampling station shown in this
figure, room is provided for a
minimum of 25 different core-sample
monitoring probes without destroying
the effectiveness of that site
during the life of the monitoring
program.
USE OF DATA
All analyses of plant, soil,
and water samples from hazardous
waste land disposal monitoring
systems should be made under
accurate, standard-method procedures
by an accredited laboratory. Also,
considering the value of such data
in determining the effectiveness
of a disposal site's pollutant
removal capability and the usefulness
of these data in the design and
operation of other disposal sites,
it is recommended that a copy of
all data collected be filed at a
state or Federal scientific agency.
Background data on all potential
pollution-dissipation regimes should
be obtained at all sample stations
just prior to the first application
of waste material on the disposal
land. Then after the site has been
placed in service, subsequent
sampling should be on a frequency
and in a manner described in the
following discussion on monitoring
the various regimes.
Atmospheric dissipation of
volatilized chemical compounds from
toxic waste disposal lands generally
is limited to gases such as hydrogen
sulfide, ammonia, and methane.
Under prevailing land disposal prac-
tices, none of these ingredients
are apt to be present in high enough
concentrations to cause a major
126
-------
OISI
*
*
.
P
SITE
*
•
•
*
f 10'
, SAMP
* STJiT
X
I
H
x 10'
L1H6
I OH
-y
EXPLANATION
RECOMMENDED
• HELL
* OjR» 'I ,\
_ !«)' ».
* * # * #
'* * « * #
* * * * * i
2'
1 * * * * *f
SIRE AH-
STATION
10.WJJ
f rl- "T- t
Figure 1. positioning of for
sites.
127
-------
hazard to public health or pose
a serious pollution threat to other
parts of the environment. Specia-
lized monitoring facilities normally
should not be necessary for this
particular regime.
Plant uptake of toxicants can
be evaluated by using chemical
analysis data obtained from a select
number of composite samples of
vegetation collected periodically
from the sampling stations situated
throughout the disposal area. The
reason for this sampling is to
ascertain the quantity of pollutants
leaving the field in harvested
portions of crops, or being left
on the field as unharvested plant
residue. It seems advisable to
collect plant samples just at harvest
time, or if the entire plant is
left in the field, after the plant
becomes dormant in the late fall.
Soil retention can be monitored
using chemical analyses of soil
core samples obtained from the
entire vertical column of earth
material within the disposal area
and contiguous lands. A minimum
of 9 and no more than 25 core test
stations as illustrated in Figure
3 should be established on every
individual parcel of land receiving
hazardous waste material. At each
of these stations core samples of
the entire earth material profile
should be collected twice yearly,
one just after the spring groundwater
recharge season ends, and the other
approximately 6 months later after
crops have been harvested but before
the late-fall groundwater recharge
period begins. In the humid
northeastern part of the United
States, these most desirable sampling
periods occur each year between
about May 1 and June 15 in the
spring and from about September
15 to November 1 in the fall.
Initial soil core test probes
made to obtain background data
should be placed at the center of
each sampling station. Subsequent
cores may be taken at any of the
2-ft grid intersection points within
the station. In every case, the
core hole should be kept open for
approximately 24 hr and then a
water-level reading obtained to
provide water-table gradient
information. Then the hole should
be refilled to the surface with
compacted clay or dry bentonite.
This is necessary to prevent later
entry of pollution from the surface.
All core tests should extend into
dense impermeable clay or similar
material proved by test drilling
or coring to underlie the entire
disposal-land area. Such an
impermeable barrier to downward
flow must lie at a depth everywhere
greater than the lowest water-table
elevation.
Since the primary reason for
this sampling procedure is to
determine both horizontal and
vertical movements of toxicants
in the earth profile, analyses
should be made of at least every
5-ft interval of the core or at
closer intervals if certain thinner
zones prove to be carrying much
of the total pollutant load.
Overland runoff from the
disposal area may not ever occur.
However, if it does happen frequently
and in appreciable amounts,
monitoring facilities must be
provided to obtain representative
water samples and corresponding
volume-of-flow measurements.
Sampling should be done throughout
the entire period when overland
runoff is occurring. The data can
be used to plot chemical concen-
trations and volume-of-flow graphs.
A comparable monitoring procedure
can be followed if drainage-tile
discharge is associated with a land-
disposal project.
Groundwater toxic chemical
pollution from hazardous waste land
disposal sites should be insigni-
ficantly minimal if the site and
contiguous land is underlaid by
only dense, impermeable clay or
shale deposits. In such earth
materials, where the rate of
groundwater movement nay be less
than 1 ft/yr, toxic chemical buildup
and the movement of toxicants beneath
affected lands can be readily and
accurately defined by chemical
128
-------
analyses of earth material samples
obtained from only a few strate-
gically placed core tests as
previously discussed. However,
if the unconsolidated earth material
above impermeable bedrock contains
extensive water-bearing stringers
or beds of silt, sand, or gravel,
core test data may have to be
supplemented by chemical analyses
of groundwater samples obtained
from properly placed observation
wells in each water-bearing unit.
Each observation well must be
screened opposite only that
layer under observation and
isolated from all others with casing
and cement grout or bentonite, from
the top of the screen to land
surface. All observation wells
required in such cases are best
placed in a cluster near the center
of each sampling station. The
wells installed can be measured and
sampled on a routine basis so that
accurate hydrographs, water table/
piezometric surface maps, and
chemical constituent fluctuation
graphs may be constructed from
the data.
129
-------
ASSESSING SYNTHETIC AND ADMIXED MATERIALS FOR LINING LANDFILLS
Henry E. Haxo,. Jr.
Matrecon, Inc.
Oakland, California
INTRODUCTION
The need to develop practical
and effective methods for controlling
the leachate generated by water
percolating through a landfill and
entering and polluting the nearby
groundwater system has become
increasingly apparent (1, 2).
Lining the landfill with an
impervious barrier and diverting
the leachate for final disposal
is a potential method of controlling
leachate. A large number of
materials from other technologies
are available which have been used
to prevent seepage of water and
various liquid wastes in pits,
lagoons, reservoirs, canals, etc.
(2-23). In spite of these wide
uses, there is almost no information
with respect to the effects of
landfill leachate upon the properties
and performance of these liner
materials. Certainly there is no
comparative information or
information that can be used in
selecting specific materials for
use in a landfill application.
It is to fill this need that the
U.S. Environmental Protection
Agency's Solid and Hazardous Waste
Research Laboratory in Cincinnati
is sponsoring this experimental
study to assess 12 specific liner
materials under exposure to leachate
in simulated landfills.
The liner materials in this
test program are now being exposed
to landfill leachate. In November
1975, after 12 mo exposure, a set
of these materials will be recovered
and tested. A duplicate set will
be recovered and tested in November
1976, after 2 yr exposure.
This paper is a. preliminary
report of the work carried out so
far on this project. The approach
and methodology to assess the
materials are outlined. The
experimental worK performed, the
significant results obtained, the
observations, and the type of
information that should be generated
over the next 2 yr are presented.
OBJECTIVES OF STUDY
The overall objectives of this
project are:
i To estimate the effective
lives of 12 liner materials
exposed to prolonged contact
with landfill leachate
under conditions comparable
to those encountered in
a sanitary landfill. The
materials were specifically
selected as being useful
for lining sanitary
landfills.
i To determine the effects
of sanitary landfill
leachate on the physical
properties of liner
materials after their
exposure for 12 and 24
mo. Twelve liner materials
(six membrane and six
admix) are mounted in the
bases of 24 simulated
130
-------
sanitary landfills; 42
smaller specimens (of 20
additional membranes) are
buried in the sand placed
above the mounted liners.
To estimate and compare
the relative long-range
costs of these materials
as sanitary landfill liners,
including materials and
installation costs, and
the cost benefits of better
performance and longer
durability of the liners.
BACKGROUND
I *>achate Generation in a Sanitary
H
The generation of leachate
*n a landfill is the result of water
entering the fill, percolating
through it, and picking up many
soluble materials and soluble
oroducts of chemical and biological
reactions, which could pollute the
croundwater. Water can enter a
till by such means as precipitation,
spring or groundwater draining
in *ne fill> or accidental flooding.
Sites are selected and sanitary
landfills are designed and con-
structed to avoid the intrusion
0£ water (1). Leachate is generated
vhere these conditions cannot always
l,e met.
The composition of landfill
jeachate varies widely and depends
On many factors, e.g., the com-
—osition and age of the refuse,
temperature, amount of available
oxygen, etc. It contains inorganic
and organic constituents. Table 1
shows the range of compositions
of leachates from sanitary landfills.
Constituents such as those given
in the table should be intercepted
and prevented from entering and
polluting groundwater. Use of an
impervious liner at the base of
a landfill could prevent this by
intercepting the leachate and
allowing it to drain to a point
Table 1. COMPOSITION OF TYPICAL
LEACHATES FROM SANITARY
LANDFILLS*
Constituent
Concentration
ranget
Iron
Zinc
Phosphate
Sulfate
Chloride
Sodium
Nitrogen
Hardness (as CaCC
COD
Total residue
Nickel
Copper
PH
200 -
1 -
5 -
25 -
100 -
100 -
20 -
)3) 200 -
100 -
1000 -
0.01 -
0.10 -
4.00 -
1700
135
130
500
2400
3800
500
5250
51,000
45,000
0.8
9.0
8.5
*Reference 23.
fAll values except that for pH are in
where it can be disposed of in a
satisfactory manner.
Concept of Using Impervious Barriers
To Control Leacnate Generated in
ITandYills'
The concept of using an imper-
vious barrier as a liner for a
landfill is illustrated in Figure
1 (adapted from Figure 14 in Ref.
1). An impervious material is
placed upon a properly prepared
surface that is graded for drainage.
The amount of surface preparation
depends on the specific type of
liner material being installed and
on the soil base on which the liner
is being placed. This base must
be free of stumps and rocks and
should be compacted. The liner
material can be compacted native
soil, asphaltic concrete, polymer
membranes, or other artificial
barriers. Above the barrier is
placed a porous soil, on which is
placed the compacted refuse in the
manner normally used in sanitary
landfills. Leachate generated by
water percolating through the refuse
131
-------
FINAL
^x^Tir-nTP
*• - ' j>- *' *
^ /'* „ ,», i E'l&HT
UNEft
CLEAN 5t;
recycli-il through j i-tr. l*til tr
stabilization of tie fill.
Liivironmeiit uf a '"nffier in a
onv I rf»nnpftt in which an
!,jrrit-f nut»r, ejtxst will
ult tii.ateiy detfrrufe '.01* well it
can ^6rvi«c an«l fur.ctjon for
period*) of time, (owe of the
environmental t:on\litiorii; at the
base of a ia.'nifill should have no
adverse efft-cr on life
of a given nateridl, whereas other
conditions ecu Id Ie quite
deleteruu:. I'»Ofce ifjpoftant
conditions ih^t cc>fjtr*btite to
life ot a Lamer are:
1. The is on
a that
to allow
ani compacted
is prcsumabt'/ fret
of rocks, sturps, etc.,
that settle to
cracking of hard
liaers, A brittle or
material would fall.
2, with
no to
oxidation.
3. No light,
polymeric
itaterials,
4, Generally wet -humid
conditions, particular1/
if is
re«lllarjft
in the
of from a
liner.
S. of 40
to 70 F normally,
within the
if deconpositicw1
6. Generally acidic condition5
the leachate,
7. of i°ns
in the that
clay
Considerable
organic constituents i*
the ic
of the orgafllt
liners.
is to
continually. A
soil is placed on
top of the before
152
-------
refuse is placed. Such
a condition may allow less
impervious liners if good
drainage can be maintained.
The effects of these environmental
conditions will differ on the various
barrier materials. However, it
appears at present that mechanical
failure during installation or
Table 2. POTENTIAL MATERIALS FOR
LINING SANITARY LANDFILLS
Compacted native fine grain soils
Bentonite and other clay sealants
- Bentonite-polymer sealants
Asphaltic compositions
- Asphalt concrete
- Hydraulic asphalt concrete
- Preformed asphalt panels
laid on concrete surfaces
- Catalytically blown asphalt
sprayed on soil
- Emulsified asphalt sprayed
on soil or on fabric matting
- Soil asphalt
- Asphalt seals
Portland cement compositions
- Concrete with asphalt seals
- Soil cement with asphalt seals
Soil sealants
- Chemical
- Lime
- Rubber and plastic latexes
- Penetrating polymeric
emulsions
rubbers sprayed
- Rubber and plastic latexes
- Polyurethanes
Synthetic polymeric membranes
- Butyl rubber
- Ethylene propylene rubber
(EPDM)
- Chlorosulfonated polyethylene
(Hypalon)
- Chlorinated polyethylene
(CPE)
- Polyvinyl chloride (PVC)
- Polyethylene (PE)
during operation of the fill due
to settling of the soil may be the
most significant source of failure
of a liner.
Potential Materials for Lining
Landf'ilTs"
Typical of the wide range of
materials that have been or are
being used as barriers to the seepage
of water and hazardous toxic wastes
in holding ponds, pits, lagoons,
canals, reservoirs, etc., are those
listed in Table 2. Selection of
liner materials for a specific job
depends upon the type of fluid or
waste being confined, the types
of materials that can perform, the
lifetime needed, and economics.
Often several materials can be used
and the choice then becomes one
of economics and the length of time
which the liner should function.
At times it may be desirable to
use combinations of materials.
GENERAL APPROACH TO
EVALUATION OF LINER MATERIALS
Taking into account the wide
diversity in the types of materials
that are being considered for lining
landfills and the urgent need for
information regarding the relative
merits of the various liners and
their expected lifetimes in a
landfill environment, the following
overall approach is being taken:
1. Select for exposure testing
12 specific liner materials
from the various types
of liner materials that
have been successfully
used in lining pits, ponds,
lagoons, canals, etc.,
to prevent seepage of water
or various wastes and that
appear suitable for lining
sanitary landfills. Cost
factors and performance
requirements suggest thin
liners, which also should
accelerate the effects
of leachate.
133
-------
Expose liner specimens
individually to leachate
under laboratory conditions
that simulate as closely
as possible those condi-
tions a liner would
encounter at the bottom
of a real landfill. The
simulated sanitary landfills
should be so designed and
constructed as to ensure
anaerobic conditions, and
the leachate generated
should be representative
of the leachate generated
in sanitary landfills.
Expose specimens of suf-
ficient size so that
physical tests can be made
to measure the effects
of exposure to leachate
and, if appropriate, a
typical seam can be
incorporated for testing.
Subject the liner specimens
to appropriate tests for
the specific type of liner.
Properties would be measured
that could be expected
to reflect on the perform-
ance of the liner in
sanitary landfills. The
tests shown in Table 3
are those used in evaluating
membrane liners. The tests
of the admix liners are
given in Table 4.
Measure the properties
of the specimens before
exposure and after 1 and
2 yr exposure to leachate.
Assess the performance
of the respective liners,
and from the changes in
their properties, estimate
their respective lifetimes
in the landfill environment.
A primary objective of
this project is to make
an estimate of the respec-
tive lives of the 12 liner
materials in the landfill
environment. To make such
an estimate, it is neces-
sary to determine what
Table 3. TESTING OF POLYMERIC
MEMBRANE LINERS
Water permeability, ASTM E96.
Thickness.
Tensile strength and elongation
at break, ASTM D412.
Hardness, ASTM D2240.
Tear strength, ASTM D624, Die C.
Creep, ASTM D674.
Water absorption or extraction at
RT and 70 C, ASTM D570.
Splice strength, in peel and in
sheer, ASTM 413.
Puncture resistance--FED. Test
Method Std. No. 101B, Method 2065,
Density, ash, extractables to
assess composition.
Table 4. TESTING OF ADMIXED LINER
MATERIALS
Permeability
Density and
voids
Water swell
Compressive
strength
Viscosity,
sliding plate
of asphalts
Microductility
of asphalts
Back pressure perinea-
meter (Ref. 24)
ASTM D1184 and D2041
California Division
of Highways 305
ASTM D1074
California Division
of Highways 348
California Division
of Highways 349
134
-------
constitutes the point of
failure of the liner.
The function of a liner
is to reduce or prevent
leakage of leachate. When
seepage or leakage through
a liner reaches an "unsat-
isfactory" level, then
the liner has failed.
Such failures could arise
from:
-- Cracking, breaking,
or tearing of the liner
due to ground settling,
rocks, etc.
-- Puncturing due to rocks,
stumps, plant growth, etc.
-- Failure of the seams
-- Disintegration of the
liner due to solution by
or reaction with the
leachate.
The ability of the liner
material to maintain its
integrity in the environment
will be measured by
observing the seepage
through the liner and the
changes in properties
during exposure to leachate.
Seal the liner specimens
in individual simulated
landfills so that whatever
seepage might come through
can be collected and tested.
This required special
efforts to avoid leachate
by-passing the liner or
channelling through the
liner, particularly in
the cases of soil cement
and soil asphalt liners.
Create equal conditions
in all simulated fills,
so that valid comparison
between liners can be made.
To accomplish this, fill
the simulated landfills
with well-compacted,
shredded municipal refuse.
Compaction, composition,
and amount of refuse should
be as equal as possible
in each of the 24 cells
so that a relatively highly
concentrated and equal
leachate is generated in
all the cells.
8. Determine the composition
of the shredded refuse
from a blend of grab samples
taken during the loading
of the cells.
9. After the refuse in the
cells is saturated, i.e.,
brought to "field capacity,"
generate leachate by adding
1 in. of tap water every
2 wk (26 in./yr) and allow
leachate to pond on the
liner at a depth of about
1 ft by draining and
collecting leachate every
other week.
10. Monitor the simulated
landfills and characterize
the leachate during exposure
period.
Testing of the leachate has
been limited to determining
temperature, levels of leachate
in generators before collection,
amount of leachate collected, total
solids, pH, chemical oxygen demand
(COD), total volatile acids (as
acetic acid), acetic acid, propionic
acid, isobutyric acid, butyric acid,
isovaleric acid, valeric acid, and
caproic acid. These tests are
needed to characterize the leachate,
to test for the uniformity of the
leachate among the various
generators, and to measure some
of the organic constituents of the
leachate. Most of the liner
materials under test are organic
in composition. It can be expected
that some of these organic components
of the leachate could swell or
otherwise deteriorate the liner
materials. Of particular interest
is the butyric acid, which can
degrade many rubber liners used
in chemical equipment.
In addition to the six membrane
liner materials that are mounted
and being tested as barriers in
the bases of the simulated landfills,
135
-------
approximately 20 additional membranes
had undergone preliminary testing
and were available for exposure
testing. As these materials included
variations in suppliers, thickness,
composition, and use of fabric
reinforcement, their exposure to
leachate could give additional
information as to the effects of
these variables. Also, it would
give us the opportunity to check
various adhesion systems and to
determine whether exposure to
leachate on both sides of a test
specimen would yield the same results
as exposure to one side, as
encountered with the barrier
arrangement.
Consequently, strips (2.25
in. X 20 in.), most of which
incorporated seams, were coiled
and buried in the sand above the
barrier specimens. Most of the
tests to be performed on the larger
barrier specimens can be performed
on these strips.
SELECTION OF SPECIFIC MATERIALS TO
TEST AS BARRIERS IN SIMULATED LANDFILLS
The selection of the specific
specimens of liner materials for
testing as barriers involved two
major steps:
1. selecting a broad class
of membrane and admix types
of material
2o within each class, selecting
a specific material or
composition.
At the outset, the Solid and
Hazardous Waste Research Laboratory
specifically eliminated soils, as
they were being tested in other
studies. The following factors
were considered in selecting the
12 classes of materials that would
be included in the test program:
1. inclusion of as broad a
range of materials as
possible
2. successful past use of
material as barriers to
prevent seepage of water
or various wastes in pits,
ponds, lagoons, canals,
etc.
3. level of permeability
offered by the material
4. anticipated ability of
the material to resist
changes in permeability
and physical properties
when exposed to leachate
in landfill environments
5. compatibility of the
materials system with
landfill operations
6. costs of materials and
installation.
After selecting the broad class
of material, a specific material
had to be selected. In making this
final selection, the following
factors were considered:
1. thickness of each material
selected would be typical
of that normally employed,
except that thin liners
would be selected so as
to accelerate the effects
of leachate
20 high quality compositions
would be used; e.g., in
selecting specific membranes
from those available, the
membrane of a given class
with best physical
properties was generally
selected.
We did not attempt to get liner
samples from all possible liner
producers, but tried to select
specific liners that were
representative of the respective
classes of materials.
The specific liners selected
and mounted as barriers in the bases
of the simulated landfills include
six flexible synthetic polymeric
membranes and six admix liner
136
-------
materials. They are listed in Table
5 with their respective thicknesses.
flexible Synthetic Polymeric
Membranes
This group of liner materials
is based on a series of synthetic
rubbers and plastics produced from
petrochemical sources. These
polymeric materials are used in
a wide range of products and
represent considerable variation
in chemical and physical properties.
Each is generally compounded with
other ingredients, e.g.,, fillers,
plasticizers or oils, antidegradants,
curatives, etc. Narrow sheeting
or membranes are produced by
calendering or other coating
processes as unsupported film or
sheeting, or with fabric
reinforcement to increase tear
strength, particularly for
installation (25). These membranes
or sheeting are seamed in a factory
Table 5. LINER MATERIALS SELECTED
FOR LEACHATE EXPOSURE TESTS
Material
Thickness
polymeric liner membranes
Polyethlyene (PE) 10 mils
Polyvinyl chloride (PVC) 20 mils
Butyl rubber 63 mils
Chlorosulfonated
polyethylene (Hypalon)
nylon scrim reinforced 34 mils
Ethylene propylene
rubber (EPDM) 51 mils
Chlorinated poly-
ethylene (CPE) 32 mils
Admix materials:
Paving asphalt concrete 2.2 in.
Hydraulic asphalt
concrete 2.4 in.
Soil cenent 4.5 in.
Soil asphalt 4.0 in.
Bituminous seal 0.3 in.
Emulsion asphalt on
fabric 0.3 in.
or shop to make large prefabricated
panels that are transported to the
pit site and assembled in the pit
to form the completed liner. The
following operations, therefore,
become involved in the ultimate
installation of membrane liners:
1. production of the polymer
2. manufacture of the rubber
and plastic sheeting or
film
3. fabrication of prefabricated
liners
40 field installation of the
liners.
A single organization can be
involved in two or more of these
steps such as in the PVC liner
industry.
The composition of the polymeric
liners can vary considerably amoung
the various producers and to some
extent between quality lines of
a given producer. Consequently,
care must be taken in generalizing
on the performance of a given polymer
in membrane liners.
Comments on the specific
polymeric liner materials used in
the test are given below:
Polyethylene (PE). Films of
PE have a very simple composition
consisting primarily of the
hydrocarbon polymer, polyethylene,
plus a small amount (ca.1%) of an
antidegradant and a few parts of
a carbon black. Thus, the
potentially extractable fraction
of this film is very low. These
membranes are relatively low in
cost and have a great resistance
to bacteriological deterioration.
They can be heat sealed in the
factory to fabricate large panels,
but are usually seamed with gum
tape in the field in assembling
the final liner. PE liners must
contain black to be resistant to
light. Although PE is more
impermeable to water than is
plasticized PVC, the PE films
normally available for agricultural
137
-------
and industrial applications
occasionally have pinholes and
blisters and, therefore, in practice
are not as watertight as the PVC
films. Some pinholes were
encountered in the film as received;
however, the sections mounted as
barriers are carefully selected
so that no pinholes were present.
Plasticized Polyvinyl Chloride
(PVC). Films of this composition
are the most widely used flexible
liners. They are available in 10-
to 30-mil thickness; the bulk is
used as unsupported film, and the
remainder, with fabric reinforcement.
The PVC compound contains 30% to
50% of one or more plasticizers
to make the films flexible and
rubber-like. It also contains 2%
stabilizer or antidegradant and,
at times, fillers. There is a wide
choice of plasticizers that can
be used with PVC,depending upon
the application and service
conditions under which the film
will be used. PVC generally holds
up well in burial tests; however,
in some liner applications, PVC
films have deteriorated, presumably
due to the specific plasticizer.
Some plasticizers can be degraded
by microorganisms and are soluble
to a limited extent in water. On
exposure to weather with its wind,
sunlight, and heat, PVC liner
materials can deteriorate badly
due to loss of plasticizer and to
polymer degradation. Plasticized
PVC films are quite resistant to
puncture, relatively easy to splice,
and available in wide sheets.
Butyl Rubber Sheeting. Butyl
rubber is a copolymer"of a major
amount of isobutylene (97%) and
a minor amount of isoprene to
introduce unsaturation in the rubber
as sites for vulcanization. A
vulcanized butyl rubber compound
is used in the manufacture of the
sheeting, which is available in
either unsupported or fabric-
reinforced versions of 20- to 125-
mil thickness. Butyl rubber has
excellent resistance to permeation
of water and swelling in water.
The permeability factor for butyl
rubber is 0.119 perms per mil.
Giving butyl a relative water
permeability index of 1.0, PE rates
1.9 and PVC, 59. Butyl rubber has
poor resistance to hydrocarbons,
but is quite resistant to animal
and vegetable oils and fats. The
butyl rubber compounds have good
resistance to water and contain
low amounts of extractable material.
Overall they age very well, although
some compounds will ozone crack
on long exposure. In outdoor
exposure in water management use,
butyl rubber sheeting has shown
no degradation after 20 yr of
service. Some of the recent
compounds contain minor amounts
of EPDM to improve ozone resistance.
Obtaining good splices of butyl
sheeting, particularly in the field,
continues to be a problem.
Chlorosulfonated Polyethylene
Sheeting (Hyp"alpn). This synthetic
rubber is made by the chloro-
sulfonation of the plastic
polyethylene. In liners, it is
used in unvulcanized compounds
containing at least 45% rubber.
The other ingredients are
predominantly fillers. Most of
the Hypalon liner sheeting is made
with fabric reinforcement (e.g.,
nylon scrim). It and has good
puncture resistance, is easy to
splice by cements, solvents, heat
and/or mechanical "zipping," and
has good characteristics with respect
to aging, oil resistance, and
bacterial resistance. It has been
reported successfully used for
lining holding pits and ponds in
mining operations where highly acid-
contaminated fluids are encountered.
After PVC, it is the most used of
the polymeric flexible liner
materials.
Ethylene Propylene Rubber
(EPDMj. This synthetic rubber is
a terpolymer of ethylene, propylene,
and a diene monomer that introduces
a small number of double bonds into
the polymer chain, which are sites
for vulcanization of the rubber.
The unsaturation in the side chain
of the polymer material and not
in the main chain of the polymer
imparts good ozone, chemical, and
aging resistance. The rubber is
138
-------
compatible with butyl and is often
added to butyl to improve resistance
of the latter to oxidation, ozone,
and weathering. As it is a wholly
hydrocarbon rubber like butyl, EPDM
sheeting has excellent resistance
to water absorption and permeation
but has relatively poor resistance
to some hydrocarbons. It is avail-
able in sheetings of 20-to 60*mil
thickness, both unsupported and
fabric reinforced. Special attention
is required in splicing and seaming
this material.
Chlorinated Polyethylene (CPE).
This relatively recently developed
polymer is an inherently flexible
thermoplastic produced by chlorin-
ating high density polyethylene.
Sheeting of CPE makes durable linings
for waste, water or chemical storage
pits, ponds or reservoirs. CPE
withstands ozone, weathering and
ultraviolet and resists many
corrosive chemicals, hydrocarbons,
microbiological attack and burning.
Compounds of CPE are serviceable
at low temperatures and are
nonvolatile.
Results of the laboratory
testing of these six polymeric liner
materials, as received from the
respective suppliers and prior to
exposure to leachate, are given
in Appendix A.
Admix Liners
The admix or formed-in-place
liner systems include hard surface
linings and soil sealants. They
are made by:
1. importing an admixed
material, such as asphalt
concrete, and placing it
in thicknesses of 2 in.
or more
2. mixing Portland cement
or asphalt with the in-
place soil (or sometimes
with imported soil) to
form a hard surface 4 to
6 in. thick
3. spreading on surface sealant
materials, such as emulsion
seals, rubber latexes,
resin solutions, expanding
clays or various forms
of asphalts.
The four hard surface liners
being tested are asphalt concrete,
hydraulic asphalt concrete, soil
cement, and soil asphalt. Hot-
sprayed canal lining asphalt and
a cold-applied asphalt emulsion
sprayed on fabric are the two soil
sealants being tested.
Asphalt Concrete and Hydraulic
Asphalt Concrete. Conventional
asphalt concrete, hot-mixed and
hot-laid, is widely used for paving
and is readily available.
Contractors are experienced in its
placement and have the necessary
equipment. It presents a hard
surface resistant to traffic and
impact forces. It is resistant
to acids and to aging, especially
in the absence of light and air.
It is designed to have a voids
content of about 5%, necessary for
the stability required for pavements.
It is, therefore, not completely
impervious and may require a surface
treatment in-situ to seal the voids.
None was applied in the asphalt
concrete being tested in this
project.
Hydraulic Asphalt Concrete.
This concrete, also hot-mixed and
hot-laid, is specially designed
to be impervious. Imperviousness
is achieved by controlling the
gradation of the aggregate and the
asphalt content to obtain a virtually
voidless structure after compaction.
Because it is voidless, it is more
susceptible to displacement and
rutting under traffic than
conventional asphalt concrete and,
therefore, is not suitable for
highway pavement. Its- other
properties are similar to asphalt
concrete. Hydraulic asphalt concrete
is mixed, laid, and compacted with
the same equipment used for
conventional asphalt concrete, but
is more difficult to handle. Its
cost is higher because of the extra
work necessary in handling, the
more stringent gradation requirements
and the higher asphalt content.
139
-------
Soil Cement. Soil cement is
made by mixing the in-place soil
with Portland cement and water,
and compacting the mixture. As
the Portland cement hydrates, the
mixture becomes a hard, low-strength
Portland cement concrete. Soil
cement is sometimes used as a surface
for pavements with low-traffic
volume, and is extensively used
for the lower layers of pavements,
where it is called "cement-treated
base." Strong soil cement can be
constructed with many types of soil,
but permeability varies with the
nature of the soil: the more granular
the soil, the higher the perme-
ability. With fine-grained soils,
soil cements with permeability
coefficients of about 10 6 cm/sec
are achievable. In practice, surface
sealants are often applied to the
soil cement to obtain a more
waterproof structure. Aging
characteristics of soil cement are
good, especially under conditions
where wet-dry and freeze-thaw cycling
are minimal. Some degradation of
the cement can be expected in an
acid environment.
Soil from the Radum quarry
near Pleasanton, California, which
has been proposed as the site of
a future landfill, was used for
preparation of the soil cement,
with Type 5 (sulfate-resistant)
Portland cement. Since the fines
content of the Radum soil was lower
than optimum for soil cement, a
few percent of nonswelling clay
(kaolin) was added for some of the
tests.
Soil Asphalt. Soil asphalt
of mixed-in-place asphalt surfacing
is made by mixing a liquid asphalt
with the in-place soil or with
imported aggregate. It is widely
used for low-cost pavements for
low volume traffic. Permeability
characteristics can be controlled
by the amount and type of asphalt
added. Soil asphalt is more flexible
and resistant to cracking than
asphalt concrete or soil cement.
It is resistant to acid and has
good aging characteristics in the
absence of light.
Liquid asphalt grade SC-800
was used to prepare the barrier
specimens because it is essentially
nonvolatile; MC-type liquid asphalts
would be expected to leave voids
when the kerosene diluent evaporated.
Laboratory specimens prepared
using soil from three different
locations showed that impermeable
soil asphalt could be made from
any of the three. Soil from the
Radum quarry was selected because
the location may become a landfill
site.
Bituminous Seal--Catalytically
Blown Asphalt.Bituminous seals
of buried asphalt membranes have
been used extensively as linings
for canals and reservoirs and to
seal off layers of expansive soils
under pavements. This type of
asphalt is produced by air-blowing
in the presence of a catalyst
(phosphorous pentoxide or ferric
chloride), which produces an asphalt
which has a high softening point,
yet remains flexible at low temper-
atures. Membranes are applied to
compacted, smooth soil surfaces
by spraying the hot (200 to 220
C) asphalt in two successive applica-
tions to ensure a continuous film
free of pinholes and holidays.
Recommended application rates are
4.5 to 6.8 kg/sq m (1 to 1.5 gal/sq
yd) to form a film 5- to 8-mm thick
(3/16 to 5/16 in.). When cooled,
the membrane is flexible, tough,
and impervious to water. It is
resistant to acids, but not to oily
materials. Aging resistance is
good when protected from light.
It is usually covered with a pro-
tective layer of soil to prevent
damage by traffic and deterioration
by light.
Bituminous Seal--Fabric Plus
Asphalt Emulsion. Emulsions of
asphalt in water can be applied
at temperatures above freezing.
They form continuous films of asphalt
after breaking of the emulsion and
evaporation of the water. The films
are less tough and have lower soft-
ening points than films of hot-
applied, catalytically blown asphalt.
140
-------
Toughness and dimensional stability
can be achieved by spraying asphalt
emulsions onto a supporting fabric.
Fabrics of woven jute, woven or
nonwoven glass fiber, and nonwoven
synthetic fibers have been used
with various anionic or cationic
asphalt emulsions to form linings
for ponds and canals and as
reinforcing patches under asphalt
concrete overlays to prevent
"reflection" of cracks in the old
pavement beneath. Seams in the
supporting fabric are often sewn
with portable sewing machines after
the fabric is placed. Nonwoven
polypropylene fabric coated with
asbestos-filled anionic asphalt
emulsion was supplied already
prepared for installation as
barriers.
Physical test data and com-
position information on the admix
liner specimens which were mounted
as barriers in the simulated land-
fills are presented in Appendix B.
likely source of liner failure,
it was decided to incorporate seams
in all the test specimens being
exposed. Either factory seams or
the recommended practice for the
specific membrane being installed
were used. Adhesives are often
designed for specific films,
depending upon the polymer and even
upon the specific compounding recipe
used. It may not be possible to
use a given adhesive designed for
a given polymer for all sheetings
made of that type of polymer.
Adhesives systems recommended
by the liner suppliers for the
various membranes are being tested.
Test joints have been incorporated
in the test strips buried in the
sand above the barriers in the
leachate generators.
CONSTRUCTION OF SIMULATED LANDFILLS
AND INSTALLATION OF LINER SPECIMENS
Seaming of Liner Specimens
Critical to the effective
performance of polymeric membrane
liners for ponds and sanitary
landfills is the capability of
making large impervious sheets of
them. The liners are manufactured
in relatively narrow widths of
sheeting that must be spliced
together either in the field or
in the factory to make continuous,
large, impervious sheets, sometimes
many acres in area. Usually the
panels are prefabricated from the
narrow sheets in the factory or
shop, brought to the site, and then
spliced together in the field.
Therefore, in a normal field
installation there are both factory
and field splices. In the usual,
favorable factory environment, more
durable seams can be made using
electronic sealing, "solvent
welding," or possibly heat curing
adhesives. Seaming in the field
can pose many problems.
As seams may be the weak point
in installed liners and the most
Design and Construction of the
Simulated Landfills
The design of the individual
simulated landfills (Figure 2) has
the following features:
1. It is made of two parts,
a concrete base in which
the barrier and strip
specimens are placed and
a 2-ft-diameter steel pipe,
10 ft high, in which the
ground municipal refuse
is compacted. This design
allows for easy dismantling
and recovery of the exposed
specimens of liner
materials.
2. The liner test specimen,
2 ft in diameter, is mounted
in the concrete base, the
interior of which is coated
with epoxy resin.
3. The liner test specimens
are sealed in place so
that seepage can only be
through the liner specimens
141
-------
and, thus, the permeabil-
ity of the liner can be
measured.
A 10-ft-high, 2-ft-diameter
steel pipe, with a 2-in.
flange of 0.25 steel at
the bottom, was placed
and sealed on the base,
then filled with ground
municipal refuse. The
pipe is made of 12-gauge
spiral weld steel.
The polyethylene that lines
the pipe was selected over
epoxy resins because of
its low cost and its
acknowledged inertness
to degradation.
, tf MAW HOCK >- THICK
iUILDCED «EFl»E
COMPACTED TO I FT.
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_ LEiCIUU
DMIN FROM MFU»
TO COLLUTIOM IA4
V •
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in
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l/JJi.:'.'-.'.'.-.''--'.^^
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. 4OIL C.OVIR
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IIFU1E COCUKN-
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Jii *AND
J5: LINEI SPECIMEN
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_£i^l Q HAVEL
THIU LINUTO COLLECTION U4
Figure 2. Scliematic drawing of
leachate generator and
cell in which the liner
materials are being ex-
posed to leachate under
conditions simulating
sanitary landfills.
6. Collapsible plastic bags
are used for collecting
the leachate to avoid
possible entry of air into
the generators.
7. There is a system for
collecting leachate both
above and below the liner
barrier.
8. To determine the level
of leachate in these
simulated landfills,
standpipes were placed
in four of them at the
outlet above the liners.
Twenty-four of these simulated
landfills have been constructed
at the Sanitary Engineering Research
Laboratory of the University of
California, Berkeley. The site,
at the Richmond Field Station of
the University, on San Francisco
Bay, has a moderate and uniform
temperature over the entire year,
mostly in the 55 to 60 F range.
The 12 liner materials were
mounted in duplicate in the 24
generators. Twelve of these
generators will be dismantled and
the liners removed and tested after
12 mo exposure to leachate and the
other 12 after 24 mo exposure.
Concrete Bases. The concrete
bases were cast individually using
a steel form in the top to give
the interior shape of the base.
This base has a horizontal ledge
about 6 in. below the rim on which
the liner specimens were mounted
and sealed (Figure 3). The
irregularities in the interior of
the base were filled with an epoxy
resin (Colma-Dur-Sika, Lyndhurst,
New Jersey)--sand grout. In
addition, because of the irregularity
of the rim of the concrete bases,
a 3-in.-wide ring of epoxy-sand
was cast on the top to give a smooth
mating surface against which the
flange on the pipe could be placed.
The interior surface of the bowls
and the outside top surface of the
bases were coated with an epoxy
142
-------
PIPE WITH WELDED [LANQE
WE.LD-
•' •>'•• "\vid; lava''^':•'•••"'•:'.-''l^/';''• -I--rr
•'"" »'v;.'^~^!!^V^^gp^^2^2^^'>T
: •«.'• •'•: •:''..'^^; '^;_-'•'"• ' »
''••••''•.':•'• '."T1"". • '••"•:'''•''*£*
3NCEETE -^-rr:-.-. ! -'•
Figure 3. Base of leachate generator
with membrane barrier.
resin (Concresive 1170--Adhesive
Engineering Company, San Carlos,
California) to ensure air and water
tightness. Each completed base
was spark and water tested to
determine if there were any leaks
through the coating.
Drainage of Leachate. A crushed,
washed granite gravel, selected
to give a stable base on which to
compact the soil cement and the
soil asphalt, and later the refuse,
was placed in the lower part of
all the bases. A piece of glass
fiber cloth was placed above these
stones to reduce the possibility
of puncture during the compaction
of the refuse on top of the membrane
liners. Sand was placed over the
membranes to protect them from
possible damage by sharp pieces
of refuse. Thin-wall PVC tubes
cast into the concrete bases provided
conduits for installation of the
drainpipes. ABS resin pipe was
used for drainage and sealed into
place in accordance with detail
B in Figure 4. The pipe was slotted,
as shown in the drawing, and covered
with a piece of glass fiber cloth
to prevent sand from clogging the
slots.
Liner Seal. All the liners
were sealed into place by casting
an epoxy ring around the periphery
after they had been placed on the
POLYETHYLENE CILM (10 MIL.)
,'PONQE NEOPRENE
«U(6E8 OA«ET W'TIJICK
^--£AiT EPOXY FLAT JINQ
ftVOOTU MATINO 6URF4CE).
•EPOXY COATINCr JO-40MIIS
MA4T1£ ^ECONDAIY
-------
3/|b PERFORATED
CA6T EPOXY
Figure 6. Leachate collection system.
DETAIL "C"
'iEAL.CLEX.IBLE FIL/Y\ IN BA6E
Figure 5. Detail of mounting
membrane liners.
concrete. Closed-cell foam gasket
material of 1/4-in. neoprene was
placed between the epoxy ring on
the base and the flange. After
the refuse had been loaded into
the generators, a bead of mastic
seal was placed around the periphery
of the flanges.
Temperature Within the
Generators.Two thermocouples were
placed in each of four generators,
one at the surface of the liners
and another about 1 ft above the
liners. (Measurements to date have
shown temperatures in the generators
to be less than 66 F (18.9 C) since
the time the refuse was placed.)
Leachate Collection System.
The system devised to collect
leachate both above and below the
liners and yet maintain the anaerobic
conditions within the generators
is shown in Figures 6 and 7. It
features:
1. Polyethylene bags with
two outlets.
"Ell
EJLE
D"
®
11
POLYETHYLENE .010" SHEET U)
UtAT SEALED AEOL'ND
FOUR EE>Cit*j '
*-l VS' - -OJO RtWFOKtEMENT
1/2' OD VS' 10 TUBE (2) 3"LDNtj
__rr— UtAT «»tEO -— T_
[_*. !,ytui:'j i
Figure 7. Leachate collection bag.
2. A valve on the outlet of
the drainpipe from above
the liner that is kept
closed except at the time
of draining of leachate.
The capacity of the bag
is about 2 1/2 gal. The
drain from below the liner
will be kept closed unless
leachate passes through
the liners, at which time
a similar, smaller plastic
bag will be mounted and
the leachate will be allowed
to drain continuously.
Collection and Grinding of Refuse
And Loading of Simulated Landfills
Approximately 12 tons of refuse
were collected by the Palo Alto
Sanitation Company in the residential
area of Palo Alto, California, and
were ground by Combustion Power
Company, Menlo Park, California,
over a period of a week in an Eidal
Mini-Mill Grinder (Model 100) without
classification. The shredded refuse
was delivered to the Richmond Field
144
-------
Station in three loads and was
systematically loaded into the 24
generators on a rotating basis.
The residential refuse delivered
by the packer truck to Combustion
power Company was obviously highly
inhomogeneous. Yet, to make a good
evaluation and comparison of the
effects of leachate on the 12
different liner materials, the
refuse in each of the generators
should have the same composition,
as should the leachate generated.
To accomplish this, good
blending of the refuse and uniform
loading and compacting of the refuse
in the generators were required.
Some blending of the contents of
the packer truck occurred on the
floor of Combustion Power Company
and in the feeding and grinding
of the refuse in the Eidal shredder.
However, the grinding and delivery
of the refuse took place in three
different loads and each had a
different overall appearance. To
ensure that the same composition
and amount of refuse was placed
in each of the generators, we
established the following plan for
loading the refuse into the
generators:
1. The refuse was weighed
into 30-lb aliquots and
dumped into the generators
one after another in
rotating order.
2. After each load, the refuse
was compacted, using the
two hand compactors designed
for this purpose. One
features dowel rods on
a circular board to simulate
a sheep's foot roller,
such as is used in the
compaction of soil, and
the other was concrete
cast in a polyethylene
bottle.
3. Care was taken during the
first few loads to avoid
heavy compaction because
of the possible damage
to the liners and disturbing
the test specimens buried
in the sand above the
barriers. The refuse was
difficult to compact,
however, because of its
dryness. Consequently,
1 gal of water was added
to each load after weighing
and before it was introduced
into the generators. In
addition, the weight of
the individual loads per
lift was reduced, after
the fifth rotation, to
20 Ib.
About 950 Ib of refuse, having
a water content of 12% to 151, were
added to each of the generators
in 45 to 47 loads or lifts. This
amount is equivalent to 1150 Ib
of refuse per generator of 30% water
content, or about 1240 Ib of refuse
per cubic yard at 30% water content.
Screened topsoil was added
and compacted to a depth of
approximately 1.75 ft on top of
the refuse, and 3 in. of 3/4-in.
drain rock was added on top of the
soil. In most of the generators,
it was necessary to add the rock
after the addition of water had
been started to bring the refuse
to field capacity. During this
time the refuse consolidated and
settled, allowing space for the
rock to be placed on top of the
soil. The top of the soil was given
a saucer shape so that when the
water was added it would pool in
the center of the columns and not
drain to the periphery and, thus,
possibly channel down the edges
near the walls.
Bringing the Refuse to Field
£
id
Capacity and Regular Addition oT
Water. It was planned to bring the
refuse in the generators to field
capacity over a period of 30 days.
Initial calculations, based on the
moisture analysis of the refuse
and the estimate of the water that
had been added to aid in compaction,
were that it would take approximately
1 gal water/day (5 days/week) to
reach this objective. Several of
the generators appeared to have
produced leachate early; however,
they did not continue producing,
145
-------
nor did the other generators produce
leachate. It was, therefore,
necessary to raise the addition
of water to 2 gal/day.
All of the generators achieved
field capacity within about 6 wk
and have been producing leachate
for the past 4 months. About 2
gal of water is being added every
other week, which equals 1 in. on
the top of the generators.
PRELIMINARY TEST RESULTS AND
OPERATION OF SIMULATED LANDFILLS
Properties of the Liners and Seams
Prior to Exposure to Leachate
Specimens of the liners, both
the membranes and the admixed
materials, were tested in accordance
with the tests shown above. Most
of these tests indicate general
adequacy of the liners and their
meeting the specifications set forth
by the suppliers. However, many
of these properties do not reflect
upon the actual performance of the
material as a sanitray landfill
liner. They may reflect on the
quality of the particular liner
with respect to other liners of
the same type of raw material.
The important factor will be the
change in properties that will occur
during exposure to the leachate.
Properties of the unexposed liners
are given in Appendices A and B.
At this point it seems that
two properties could have a
measurable effect on the performance
of the liners during exposure to
leachate, i.e., the swelling in
water and the permeability of the
liner material to water or water
vapor. Results of these tests on
the materials being exposed as
barriers are presented in Tables
6 and 70
Table 6. PROPERTIES OF LINER MEMBRANES BEFORE EXPOSURE TO LANDFILL LEACHATE
Type of
membrane
Hypalon w/scrim
Butyl rubber
Thickness,
mils
34
63
Water absorption
at room temp. , 1
>6.77 at 26 weeks
>0.88 at 26 weeks
Moisture vapor
transmission,
metric perms*
0.057
0.0175
Permeability,
cm/sec
0.0052
0.0029
Chlorinated poly-
ethylene
Ethylene propylene
31
>9.13 at 26 weeks
0.041
0.0033
rubber 51
Polyvinyl chloride 20
Polyethylene 10
>2.35 at 14 weeks 0.040
1.18 at 3 weeks (max.) 0.255
0.38 at 1 week (max.) 0.087
0.0053
0.0135
0.0023
*ASTM E96--66; metric perms: grams/24 hr/sq m/mm Hg; to convert to perms,
multiply by 1.S2.
146
-------
Table 7. PROPERTIES OF ADMIX LINER MATERIALS BEFORE EXPOSURE TO LEACHATE
Material
Thickness,
in.
Water swell,
mil
Coeff. of
permeability,
cm/sec
Asphalt concrete,
paving (7.1 ph-agg) 2.2
Asphalt concrete,
hydraulic
(9.0 ph-agg)
Soil cement (10%
type 5 cement)
Soil asphalt (7.0
ph soil SC liquid
asphalt)
Bituminous seal
Asphalt emulsion
2.4
4.5
4.0
0.3
0.3
0
0
17
1.2 x 10'8
3.3 x 10~9
1.5 x 10'6
1.7 x lO-3
n- 9
<10-9
Compression
strength,
% retained*
80
86
69
15
*After 24-hr immersion in water; asphalt concrete and hydraulic asphalt
concrete at 60 C, and soil asphalt and soil cement at room temperature.
The polyethylene, polyvinyl
cholride, and butyl show particularly
low water adsorption. On the other
hand, both polyvinyl cholride and
polyethylene appear to have the
greatest moisture vapor transmission.
In the case of the admixed
materials, low water swell and good
coefficient of permeability were
observed for all but the soil cement
and soil asphalt. To date, only
the soil asphalt, with its relatively
poor permeability and high swell,
has allowed water to seep through
the barrier. Preparation of this
material on a larger scale would
probably give better results than
were achieved in the preparation
of the test specimens. Difficulties
were encountered in maintaining
high temperatures during mixing
and compacting the soil asphalt.
All of the splices met the
specifications of the suppliers.
However, the electronic and heat-
sealing splices of the various
membranes made yield the greatest
strengths. As with the membranes
themselves, the splices must retain
their integrity during the exposure
period and not allow leakage of
leachate.
Performance of the Liners in Instal-
lation and Exposure to Leachate
All of the liners under test
as barriers, except one, are
performing satisfactorily. One
of the liners, the soil asphalt,
is allowing leachate to pass through.
This was the most permeable of the
liners being tested and was found
to swell the most in laboratory
tests. The leachate passing through
has almost the identical composition
as that being collected above the
liner.
The polyethylene liner gave
us problems when being placed in
the bases of the generators because
of small holes caused by creasing
and/or punctures. No leak developed,
even during compaction of the refuse,
147
-------
but it appears that this type of
liner material would be difficult
to handle and install as a liner
during landfill operations without
developing holes and tears.
Variation in Liners of the Same Type
In this project we are studying
12 different liner materials and
comparing them on the basis that
each represents its respective type
or class of material. Such an
assumption is an oversimplification,
because each liner material can
vary considerably; this is par-
ticularly true of admix liners
because of the inhomogeneity of
the raw materials.
In the case of the polymeric
membranes, there can also be
considerable variation between
materials based on a given polymer
type, whether plastic or rubber.
These variations can arise from
the following:
1. Variation in the polymer
type, e.g., grade, supplier.
2. Compound variation. Polymer
suppliers may suggest
recipes. Physical
properties normally tested
are not unique to a given
composition. Therefore,
individual liner
manufacturers generally
use different recipes,
depending on both technical
and economic factors.
In the case of PVC there
can be major variations
in the amount and type
of plasticizer and possibly
in the use of various
fillers; in the case of
rubber, there can be
variations in type and
amount of filler,
plasticizer, and curing
agent (if any).
3. Variation in the techniques
and the equipment used
in forming the sheets.
These variations can show up
in the various grades a manufacturer
might supply.
Laboratory test data on all
liners received and tested confirm
the existence of significant
variations in liners made of a given
polymer. Five different companies
supplied PVC sheeting. There is
no indication as to the source of
the PVC, but all suppliers are
producers of PVC and, presumably,
they use their own material as well
as their own recipes in the
manufacture of their respective
liner sheetings. The following
data show the range of properties
reported for PVC sheeting:
Tensile strength, psi ... 1540 • 3400
Elongation, f 260 - 240
Set, I
Modulus @ 1001 elong-
ation, psi 980
Hardness, Duro A 72
Tear, psi 270
20 - 110
1680
82
390
Water absorption,
7 days at 25 C, I
0.3 - 1.S2
These data are primarily
physical tests that characterize
the compound but may not correlate
with field performance, except
possibly for water absorption.
These physical properties are
important in the installation of
the liners, and these differences
may indicate differences in the
performance of these liners in a
sanitary landfill environment
involving long-term contact with
leachate.
In the case of other liner
sheetings, made of the same basic
polymeric material, and supplied
by different manufacturers, there
have been significant variations
in laboratory properties reflecting
different compound recipes. Though
148
-------
made of the same material, they,
too, may perform differently in
a landfill environment.
The Hypalon liners have varied
in water absorption in 2 hr at 100
C from 4.19 to 15.3 and in 70 days
at room temperature from 4.52 to
8.66; and in hardness from 73 to
83. The variations in the other
properties are largely due to the
variations in the reinforcing fabric
used. In the case of butyl, there
are significant variations in tensile
and water absorption and, in the
case of EPDM, there are variations
jn tensile and tear.
We believe that the information
obtained from the testing of all
the samples, including the strip
specimens, will give us information
as to the importance of these
variations on properties. This
information will also be helpful
in setting up performance and
compositional specifications if
such become necessary.
Characterization of the Refuse
It was the consensus of
Combustion Power and the Palo Alto
Sanitation Company personnel who
saw the refuse before it was ground
that it appeared typical of the
refuse normally collected in the
Palo Alto area and received at the
Combustion Power laboratory, except
that it appeared dry (see Table 8j.
During the filling of the
simulated landfills, a composite
grab sample was accumulated by
collecting one scoopful from each
round when adding one lift to the
24 cells. The entire composite
sample of 32.8 kg (72.2 Ib) was
separated into four size fractions
by screening through a Sweco
separator fitted with 25-mm (1-in.),
13-mm (0.5-in.), and 6-mm (0.25-
in.) sieves. The entire 4.2-kg
(9.3-lb), 6- to 13-mm fraction,
and 4.2-kg aliquots of the plus
25-mm and 13- to 25-mm fractions
were classified by hand sorting.
Table 8. CHARACTERIZATION OF COMPOSITE SAMPLE OF REFUSE (*)
Size of fraction and % of total
Classification
>25 mm 13-25 mm 6-13 mm <6 mm % in
in.) (0.5-1 in.) (0.2S-.5 in.)(<0.25 in.) total
27.0% 36.8% 12.9% 23.3% fraction
Water
Paper
Cloth
Plastic,
Wood,
food
rubber
garden,
waste
11
69
1
9
2
.9
.6
.1
.8
.2
11.
58.
1.
5.
6.
8
1
1
4
4
4.
50.
1.
2.
9.
3
S
1
1
7
17.3
29.8
„,
--
3.6
12
53
0
4
5
.2
.6
.8
.9
.1
Oils and fats
Metal
Glass, rock,
soil
5.4
15.0
2.2
4.3
28.0
4.0
45.3
0.9
7.6
14.9
149
-------
Table 8 shows the classification
of the composite sample. The content
of identifiable food waste was low.
It is assumed that the refuse must
have been collected from a neigh-
borhood where most food wastes are
flushed into the sewers through
sink disposal units. The actual
content of putrescible organic
material was somewhat higher than
shown, as some pieces of paper and
plastic in the larger size fractions
were obviously saturated with fats,
blood, etc.
Leachate Generation and Analysis
Table 9 summarizes leachate data.
Leachate levels in excess of 2 ft
have been observed in the four sand-
pipes. Such levels are higher
than expected and additional drainage
Table 9. DATA ON SIMULATED LANDFILLS AND LEACHATE;
AVERAGE VALUES FOR 24 LANDFILLS
Determination
Amt. of leachate
collected, liters
Temperature, C
Solids, 1
PH
COD, mg/l
TVAt, mg/l
Organic acids:
Acetic, mg/l
Propionic, mg/l
Isobutyric,
mg/l
Butyric, mg/l
Isovaleric,
mg/l
Valeric, mg/l
Caproic, mg/l
Total organic acids
10 Dec.
2
6.91
11.5
3.49
5.5
46,106
10,547
1,446
1,581
330
2,391
124
256
0
6,128
Date/report number
6 Jan. 3 Feb. 3 Mar.
5 8 13
5.26 4.96 4.94
10.5 11.5
3.38 3.58 3.54
5.5 5.30 5.21
58,375 45,075 43,520
10,575
2,000
1,549
497
2,275
339
697
0
7,357
Breland*
--
--
1.25
5.1
18,000
9,000
5,160
2,840
--
1,830
--
100
--
9,930
*Refercnce 26.
tTotal volatile acids, as acetic acid.
150
-------
lias been made to bring the levels
down so that the level will be at
1 ft at the time a collection is
jtia.de. Extensions are being placed
on other collection bags, which
are then raised to allow the
extensions to perform as standpipes.
All of the 24 simulated
landfills have been operating
satisfactorily and producing leachate
of quite similar composition for
•the past 4 mo. The analyses of
•the leachates averaged for the 24
simulated landfills are given in
fable 9. They are compared with
•the results of Breland on a leachate
from a control landfill at his
highest concentration (26). The
Duality of the leachate appears
to be satisfactory for testing the
liner materials.
Some problems have been
elicountered with the polyethylene
collection bags that were fabricated
out of the same polyethylene film
used in lining the generators.
The bags failed at the seams and
creases and have punctured easily.
polybutylene has been found to yield
& much more durable bag, and a
conversion to these will be made
as soon as materials are available.
Except for the first few days
o£ operation, the temperatures
-within all the simulated landfills
have remained almost at ambient
temperature of 11 to 19 C.
ESTIMATED COSTS OF POTENTIAL LINER
MATERIALS FOR LANDFILLS
One of the objectives of this
•nroject is to determine the relative
costs of the various liner systems.
•TO compare the total real costs
of liners for use in lining sanitary
landfills, the following must be
considered:
1. performance required, e.g.,
permeability
2. desired service life
3. costs of liner materials
delivered to the site
4. costs of installation,
adaptability to landfill
operation
5. certain site preparation
costs required for a given
liner material
6. soil cover costs.
Obviously, overall effectiveness
and service life will ultimately
determine the cost that can be
applied to a given liner. The
information needed to make such
estimates depends on actual exper-
ience and studies such as this.
Early in the project we
assembled the then-current cost
data on these various liner materials
for comparative purposes. As the
project progresses, these data will
be reviewed and updated. The
estimates made in October 1973 are
presented in Tables 10 and 11;
recognize that major cost increases
probably have taken place.
Basically, those costs did
not include the costs for site and
surface preparation, nor the cost
of ground cover which would be
required in nearly all cases. The
surfaces on which the liners are
to be placed must be graded and
smoothed for drainage and compacted
to prevent settling of the ground
below the liner and, in several
cases, to give a firm table on which
to compact the liner materials
(i.e., soil asphalt, soil concrete,
and the asphalt concretes). The
cost of site preparation is
essentially the same for all the
liner systems, though it is possible
that some of the liner systems may
not require as much effort in surface
preparation as others. A cover,
preferably one which is somewhat
porous, is needed as part of the
liner system. Such soil covers
will allow the large landfill
equipment, e.g., caterpillar tractors
and compactors, to operate on the
liners.
151
-------
Table 10. PRELIMINARY ESTIMATE OF COSTS* OF POTENTIAL LINERS FOR
SANITARY LANDFILLS: POLYMERIC MEMBRANES--PLASTICS AND
RUBBERS--UNREINFORCED
Thickness,
Item mils
Butyl rubber 31.3 (1/32")
Chlorinated polyethylene
(CPE) 20
Chlorosul f onated
polyethylene^ 20
Price of
roll goods
$2.25
1.58
1.66
Installed
cost*
$3.25 -$4.00
2.43 - 3.24
2.88 - 3.06
Ethylene propylene
rubber (EPDM)
Neoprene
Polyethylene film
Polyvinyl chloride
46.9
62.5
10
20
(3/64")
(1/16")
2.42
2.97
0.36
0.90
2.65 -
4.41 -
0.90 -
1.17 -
3.42
5.40
1.44
2.16
*Costs in dollars per square yard.
tSoil cover not included; membranes require some soil cover, cost of which
can range from $0.10 to $0.50/sq yd per ft of depth.
*Hypalon, with nylon scrim.
EVALUATION OF LINER MATERIALS EXPOSED
TO HAZARDOUS AND TOXIC SLUDGES
An urgent need also exists
for information comparing various
liner materials as barriers to
hazardous and toxic wastes.
Consequently, the Solid and Hazardous
Waste Research Laboratory is
sponsoring a study similar to the
landfill study in which 12 liner
materials will be exposed to six
wastes over a period of 2 yr and
the effects on properties of the
liners will be observed. Work has
been started on this project.
The performance requirements
for liner materials for confining
hazardous wastes will, of course,
differ from those for sanitary
landfills and are more stringent.
In this program soils and clays
will be included. At the present
time, 11 of the 12 liner materials
have been selected for exposure
testing. Many of these will be
the same as those tested in the
landfill project. Table 12 lists
the materials that will be exposed
to such various hazardous and toxic
sludges as acidic, alkaline,
pesticide and cyclic hydrocarbon
sludges; oil refinery tank bottom
waste, and lead waste from gasoline
tanks.
Figure 8 illustrates the type
of exposure test cell that will
be used for exposing a flexible
membrane liner. Each of the flexible
liner specimens will contain a field
type splice and will be sealed in
place with an epoxy resin. The
same basic design will be used for
the thick admixed specimens, except
that a spacer will be used between
the base of the cell and the upper
part, which will contain the
hazardous waste. In this case,
a spacer will be used and will be
sealed with epoxy. The sketch in
the upper right shows the overall
appearance of the exposure cell
with a thick admixed liner mounted.
152
-------
Table 11. ESTIMATES OP COSTS* OF POTENTIAL LINERS FOR SANITARY LANDFILLS
SOILS, ADMIXTURE MATERIALS,AND ASPHALT MEMBRANES
Type
Installed cost
Soil + Bentonite
9 Ib/sq yd (1 psf)
Soil cement
6-in. thick + sealer (2 coats — each
0.25 gal/sq yd)
Soil asphalt
6-in. thick + sealer (2 coats—each
0.25 gal/sq yd)
Asphalt concrete--Dense-graded paving
with sealer coat (Hot mix--4-in. thick)
Asphalt concrete--Hydraulic
(Hot mix--4-in. thick)
Bituminous seal
(catalytically blown asphalt)
1 gal/sq yd
Asphalt emulsion on mat
(polypropylene mat sprayed with asphalt
emulsion)
$0.72
1.25
1.25
2.35 - 3.25
3.00 - 4.20
1.50 - 2.00
(with earth cover)
1.26 - 1.87
*Costs in dollars per square yard.
Table 12. LINER MATERIALS TO BE EVALUATED IN EXPOSURE TESTS TO
HAZARDOUS AND TOXIC SLUDGES
Polyvinylcholride
Butyl rubber
Chlorosulfonated polyethylene
(Hypalon)
Bentonite clay seal
Asphalt emulsion on nonwoven
fabric
Soil cement with seal
Chlorinated polyethylene (CPE) Hydraulic asphalt concrete
Ethylene propylene rubber
(EPDM)
Polychloroprene (Neoprene)
Compacted native fine grain
soil
153
-------
Glass Cloth
Figure 8. Exposure cell for membrane
liners.
The exposure cells are being
fabricated and mounting of the
specimens will begin about May 1,
1975. Properties of the test
specimens will be measured after
6 mo and 1- and 2-yr exposures to
the various wastes„
SUMMARY
Two specimens each of six admix
and six polymeric membrane liner
materials have been mounted as
barriers in the bases of 24 simulated
sanitary landfills for 1 and 2 yr
exposure to leachate generated in
these fills. These 12 barrier
materials represent a wide range
of compositions; they are currently
being used in lining ponds, pits,
lagoons, canals, etc., to prevent
seepage of water or various wastes
and appear promising for use as
impervious barriers for lining
sanitary landfills. In addition,
42 small membrane specimens, many
of them incorporating splices, are
being exposed to leachate by being
placed in the sand above the
barriers.
The 24 simulated landfills
were uniformly filled with a shredded
municipal refuse compacted to a
density of about 1240 Ib/cu yd at
a moisture content of 30%. The
simulated landfills are functioning
properly; the conditions within
the fills are anaerobic and there
is no leakage around the liners.
The leachate being generated appears
to be representative of landfill
leachate; it is quite uniform among
the various generators so that all
the liner specimens are being exposed
to essentially the same type of
leachate.
.At this time, only the soil-
asphalt liner appears to be
inadequate. Leachate is seeping
through one specimen of this type
liner, and indications are that
the second liner of this type will
also leak, although insufficient
leachate has seeped through to be
collected at this time.
The method of sealing the
liners into the generator bases
with a cast epoxy ring has worked
out satisfactorily; except for the
soil-asphalt liner, there has been
no leakage or seepage of leachate
into the lower compartment of the
bases.
Although it has not failed
as a barrier, the polyethylene film
is sensitive to creasing and
puncturing. Not only is it being
exposed as barrier specimens in
two of the simulated landfills,
but it is also being used to line
the 2-ft-diameter steel pipes
containing the refuse and to
fabricate the leachate collection
bags. It appears, at this time,
that polyethylene film would be
difficult to handle in a landfill
operation.
Heat sealing to splice the
various membrane liners, such as
polyvinyl chloride, polyethylene,
chlorinated polyethylene, and
Hypalon, yields particularly strong
seams.
Laboratory tests of unexposed
membrane liners of the same polymer
indicate that there can be consid-
erable liner-to-liner variation
in liners of the same polymer type.
These variations probably reflect
differences in compounding and in
fabrication of the liner materials.
154
-------
The first set of 12 simulated
landfills will be disassembled in
November 1975, at which time the
barriers and buried specimens will
be recovered and tested. The
specimens will have been exposed
to landfill leachate for 1 yr.
Present plans call for the second
set of 12 simulated landfills to
be disassembled in November 1976
and the specimens tested after a
2-yr exposure to leachate.
ACKNOWLEDGMENTS
The work which is reported
in this paper was performed under
Contracts 68-03-0230 and 68-03-2134,
•'Evaluation of Liner Materials
Exposed to Leachate," and Contract
68-03-2173, "Evaluation of Liner
Materials Exposed to Hazardous and
Toxic Sludges," all with the
Environmental Protection Agency,
National Environmental Research
Center.
The author wishes to thank
Robert E. Landreth and Richard A.
Chapman, Project Officers, for their
support and guidance in these
projects. The author also wishes
to acknowledge the guidance of Dr.
Clarence Golueke and Stephen Klein
of the Sanitary Engineering Research
Laboratory, University of California,
Berkeley, with respect to leachate
generation and characterization
%nd the efforts of R. M. White,
yi. R. Mittikand technicians of
jtfatrecon, Inc., in carrying out
the experimental work involved in
these projects.
REFERENCES
Brunner, D. R., and D. J.
Keller, (1972). "Sanitary
Landfill Design and Operation,"
U.S. Environmental Protection
Agency Report SW-65ts.
Weiss, Samuel, (1974). "Sanitary
Landfill Technology," Noyes
Data Corporation, Park Ridge,
New Jersey.
3. Asphalt Institute (1966).
"Asphalt Linings for Waste
Ponds," IS-136.
4. Asphalt Institute (1969).
"Construction Specifications
for Asphalt Concrete," SS-1.
5. Ellsperman, L. M., (1957).
"Buried Asphalt Membrane Canal
Linings," Third Congress of
the International Commission
on Irrigation and Drainage,
San Francisco, Ca.
6. Ellsperman, L. M., and M. E.
Mickey (1959). "The Uses of
Asphalt in Hydraulic
Construction by the Bureau
of Reclamation," Third Annual
Kansas Paving Conference,
University of Kansas, Lawrence,
Kansas.
7. Geier, F. H., and W. R. Morrison
(1968). "Buried Asphalt Membrane
Canal Lining," U.S. Bureau
of Reclamation, Research Report
No. 12.
8. Mickey, M. E. (1961).
"Laboratory and Field Studies
of Asphaltic Materials for
Controlling Canal Seepage
Losses," Conference on Use
of Asphalt in Hydraulic
Construction, sponsored by
the Asphalt Institute,
Bakersfield, Ca.
9. Hickey, M. E. (1969).
"Investigations of Plastic
Films for Canal Linings,"
Bureau of Reclamation, Research
Report No. 19.
10. Hickey, M. E. (1971). "Synthetic
Rubber Canal Lining Laboratory
and Field Investigation of
Synthetic Rubber Sheeting for
Canal Lining--Open and Closed
Conduit Systems Program,"
Bureau of Reclamation, Report
No. REC-ERC-71-22.
11. Jones, C. W. (1971). "Laboratory
Evaluation of Canal Soil
Sealants, An Open and Closed
Conduit Systems Investigation
of Four Proprietary Materials
Proposed as Canal Soil Sealants
on Silty Sand in Laboratory
Permeameters," Bureau of
Reclamation, Report REC-ERC-
71-1.
12. Lee, Jack (1974). "Selecting
Membrane Pond Liners," Pollution
Engineering. January. "~
155
-------
A. Dodge,
Ellsperman,
G. Savage,
13. Merton, F. K., and B. A. Brakey
(1968). "Asphalt Membranes
and Expansive Soils," The
Asphalt Institute, IS-145.
14. Morrison, W. R., R.
J. Merriman, L. M.
Chung Ming Wong, W.
W. W. Rinne, and C. L. Gransee.
"Pond Linings for Desalting
Plant Effluents," U.S. Dept.
of Interior, Office of Saline
Water, R S D Prog. Report No.
602,
15. NACE (National Association
of Corrosive Engineering)
(1966). "Chemical Resistance
of Asphalt Coatings," Materials
Performance £, 81-83.
16. Phillips Petroleum Company
(1972). "Asphalt Sealed
Membranes for Pond Liners and
Erosion Control," Handbook
and Installation Guide for
Petromat Fabric, Hydraulic
Grade.
17. Portland Cement Association
(1937). "Lining Irrigation
Canals."
18. Portland Cement AsOociation
(no date). "Soil Cement Linings
for Water Reservoirs."
19. Rosene, R. B., and C. F. Parks.
Environmental Quality Conference
for AIME, Washington, D.C.,
June 7-9, 1971. "Preventing
Loss of Industrial and Fresh
Waters from Pits, Ponds, Lakes
and Canals."
20. Smith, W. D. (1962). "Canal
and Reservoir Lining with
Asphalt," The Asphalt Institute.
IS-121.
21. U.S. Bureau of Reclamation
(1963). "Linings for Irrigation
Canals," U.S. Government
Printing Office.
22. U.S., Department of Agriculture
(1972)o "Asphalt Linings for
Seepage Control: Evaluation
of Effectiveness and Durability
of Three Types of Linings,"
Technical Bulletin No. 1440, May.
23. Steiner, R. C., A. A. Fungaroli,
Ro J. Schoenberger, and P.
W. Purdom (1971). "Criteria
for Sanitary Landfill
Development," Public Works,
103(3):77-79.
24. Vallerga, B. A., and R. G.
Hicks (1968). "Water
Permeability of Asphalt Concrete
Specimens Using Back-Pressure
Saturation," J. Materials 3(1):
73-86.
25. Ewald, G. W. (1973). "Stretching
the Life Span of Synthetic
Pond-Linings," Chemical
Engineering, Oct. 1.
26. Breland, G. G., Jr. (1972).
"Landfill Stabilization with
Leachate Recirculation,
Neutralization, and Sludge
Seeding," Special Research
Problem, Georgia Institute
of Technology School of Civil
Engineering, Sept.
156
-------
APPBIDIX A
PROPERTIES OF POLYMERIC LINER MEMRANES INSTALLED AS BARRIERS
Cell Nuober
Liner So.
Material
Thickness, ra (0.001 in.)
Coefficient of water perneability,
en/sec.
1 " 7 days 9 25'C
" " 70 days C« 25«C
Puncture test, 25 •CB/min. , max. force,
elongation.
Puncture t*st, 500nra/aln. , max. force, N
elongation, BX
Splice strength, peel, k-N'/n (Ib./in. )
'' " shear. kN/a (Ib.^in.)
Hardness, Shore A, instantaneous
10 sec.
Modulus 3 1002, MPa
(lb/in2)
Modulus @ 200%, MPa
(lb/in2)
Modulus 0 3002, MFa
Ub/in2)
Tensile strength, MPa
Ub/ln2)
Elongation, Z
Set, 1.
(2)
(lb/in.)
Cr**p test^) load, N
(Ib.)
hours co failure
elongation, %
set, X
creep, en/cm, 100 hr.
(1) Method 2065, Fed. Test Methods 101
1,19
21
Polyethylene
0.25-0.30 (10-12)
N (Ib.)
nra (in.)
(Ib.) 61.9
. (In.) 19
2.73
3.54
0.61
0.38
(13.9)
(0.76)
(15.6)
(20.2)
2,20
17
Polyvinyl
Chloride
0.51-0.53 (20-21)
7.3 x
io-«
21 e
* i-J
0.95
115 (25.8)
18
(0.69)
0.70(4.0)
6.51(37.2)
98
98
8.76
(1270)
10.1
(1470)
11.6
(1680)
11.7
(1700)
320
177
72>6
(415)
7.78
(1.75)
> 72 NF
13.3
9. '5
0.10
7.10
(1030)
7.24
(1050)
7.72
(1120)
17.9
(2590)
690
667
63*0
(360)
7.78
(1.75)
> 72 OF
47.6
7»7
19
0.52
(2) ASTM 0624, Die C
8.69
(1260)
14.3
(2080)
18.2
(2640)
270
68
61.6
(352)
14.0
(3.15)
26
194
73
3.88
(3)
81
76
7.79
(1130)
12.8
(1850)
17.4
(2520)
290
77
55.5
(317)
12.7
(2.85)
12
138
51
7.5
ASTM D674 -
wide. NF =
3,21
7
Butyl Rubber
1.55-1.65 (61-65)
1.1 x 10"11
01 7
* L i
0.18
0.52
149 (33.5)
29 (1.14)
199 (44.8)
31 (1.22)
0.66 (3.8)
5.25 (30)
55
51
2.41 2.02
(350) (290)
5.31 4.21
(770) (610)
8.48 6.90
(1230) (1000)
9.93 9.86
(1440) (1430)
360 430
15 18
31.5 31.5
(180) (180)
14.0 12.5
(3.14) (2.82)
> 94 NF > 94 NF
108 111
84 63
5.4 5.2
0.23 0.23
durabbe 11 spec Imens ,
no failure.
4,22
6
Kypalon, with
0.81-0,
3.6 x
.91 (32-36)
Hf12
5,23
16
Ethylene-propylene-
1.24-1.35 (49-53)
2.3
7 • j. /
2.04
4.52
131
26
146
15
5.25
8.75
6.90
(1000)
11.8
(1710)
13.2
(1920)
250
115
cf ft
JO. U
(320)
25.3
(5.68)
(29.5)
(1.01)
(32.9)
(0.60)
(30)
(50)
81
79
5.93
(860)
9.17
(1330)
11.1
(1610)
250
106
49 0
(280)
29.8
(6.7)
> 96 NF 2.2
194
1C
1.87
253
j_7
10CM-
99
restricted portion
141
35
175
37
0.44
2.56
wi th
2.41
(350)
5.24
(760)
7.72
(1120)
10.4
(1510)
420
13
31 7
(181)
8.18
(1.84)
XIO'11
0. 47
0.61
1.90
(31.6)
(1.38)
(39.4)
(1.44)
(2.5)
(14.6)
57
54
2.41
(350)
5.24
(760)
7.72
(1120)
9.93
(1440)
400
19
31 7
(181)
6.89
(1.55)
> 143 NF > 143XF
112
79
5.6
0.18
102
78
4.7
0.14
51 ran (2 in.) long by 6.
6,24
Chlorinated
po lyethylene
0.79.0.81 (31-32
2.0 x
150
26
209
26
1.75
9.98
8.41
(1220)
12.5
(1820)
17.0
(2460)
17.0
(2460)
300
199
47 2
(270)
22.2
(5.0)
31
186
62
4.5
3 ran (0.
lo'12
2.93
1.43
5.31
(33.8)
(1.03)
(47.0)
(1.04)
(10)
(57)
85
87
3.59
(520)
5.79
(840)
8.27
(1200)
14.3
(2080)
520
230
42 0
(240)
14.1
(3.18)
47
344
129
176
3.6
2S in)
-------
PROPERTIES OF ADMIX LINERS MOUNTED AS BARJUEXS
cn
00
Installed la Cell No.
Composition of Barrier Specimen
Particle Hit distribution, %
Passing 4.76 ran, (4 oesh)
" 2.38 ro, (8 iresh/
1.19 -a-., (It a*sh)
C.593 crn, (30 n.esh)
" 0.297 on, (50 mesh)
" 0.149 m», (100 niesh)
" 0.074 rn, (200 nesh)
Sand equivalent
Liquid limit
Plastic Unit
Plasticity ir.dex
Fer.etracicrt «t 2S3C
Penetration (extracted from barrier)
Softening point, bC (°F)
Penetration index
Viscosity, capillary at 60*C, cS
Viscosity, sliding plate at 25°C, at
0.05 sec'1, «P
Vlscvs'ty, sliding plate at 25°C, at
O.OC1 sec'1, KT
Xicroductiiity at 25°C, ra
Thickness of barrier sgcclsMtn, en (in.)
Density, g./cc3 (lb/ft3)
Void ratio (vol. voids/vol. tollds), I
Uater swell nm (0.001 inch)
Coefficient of peraabllity, cm/sec. (Ref. 21)
Conpresslve strength, HPa (Ib/in )
Coxpressiva strength after 24 hr ionersion*
\ retained
Asphalt Concrete
7,13
7.1 asphalt/
100 aggregate
90.7
61.0
45.1
30.1
19.4
11.2
6.6
68
44
14.5
20.0
40
5.6 (2.2)
2.387 (149.0)
6.4
0.03 (1)
1.2 x 10-8
19.34 (2805)
15. 3* (2230)
80
Hydraulic
Asphalt Concrete
8,14
9.0 asphalt/
100 aggregate
89.4
67.1
50.9
33.7
21.5
12.4
7.2
68
62
9.7
14.5
76
-.1 (2.4)
2.416 (150.8)
2.9
0
3.3 x 10-'
18.70 (2712)
16.05 (2328)
86
Soil Cement
9,15
95 soil, 5 kaolin cl.,y,
10 Type 5 ceattnt,
8.6 water
88.9
70.8
53.7
38.8
29.2
20.8
15.0
27
17.6
non-plastic
non-plastic
11.4 (4.5)
2.169 (135.4)(drj)
0
1.5 x ID"***
13.17 (1910)
9.12 (1323)
69
Soil Asphalt
10,16
7.0 SC-800 liq, asphalt/
100 aggregate
79.2
55.8
39.9
27.3
18.5
13. i
11.4
31
17.0
non-plastic
non-plastic
1101
0.20
0.14
7
10.2 (4)
2.228 (139.1)
10.4
0.43(17)
1.7 x 1C-3
8.40 (1218)
1.27 (184)
15
Bituminous Fabric +
Seal Asphalt Emulsion
11,17 l«.ila
Cacalycically- AspSalt (free-
blown csphalt, emulsion) 4.3
4.7 kg/a2 kg/a:2 (3.9 lb/yd<)
(8.7 lb/yd2) on polypropylene
non-woven fabric
45
89 (192)
+5.2
8.5 4.5
19.3 6.0
2 29
0.8 (0.3) 0.8 (C.3)
0
< ID'9 < 10-9
Asphalt Cement and Hydraulic Asphalt Ceaent
Meaaured on voided specimen
ianersad In watair ait 60*C, Soil Aapoalt and Soil CeaMnt 1C R.T.
-------
AND
AN
Frederick G. Pohland
School of Civil Engineering
Institute of Technology
INTRODUCTION
Leaching of solid con-
stitutes from landfill disposal
of solid wastes con-
siderable attention in years.
Yet, definition of actual environ-
mental impacts has exceedingly
elusive and fraught with controversy.
Much of this is related to
past landfill procedures
which generally failed to ade-
quately plan for monitor opera-
conditions at a particular site.
In recognition of deficiencies,
on a landfill management
concept employing collection
recycle initiated at fieorgia
Tech in 1970. This research
to investigations on
control as
well as residual treatnent alterna-
tives. An overview of
recycle/treatment is pre-
herein with
supporting their intrepre-
tation. Other
(1-3),
OF
To accoraodate the objectives of
research effort, an cxperimantal
(Figure 1) to sim-
ulate landfill disposal of domestic-
solid wastes but with opportuni-
for comparison of the character-
rip ts *uff*r*«l with
4»4 Wooden Po*tt
fe ami te
in if of
3-f _J
~^
1. landfills.
1S9
ttta sc*te>
-------
istics of normal by
intercepted rainfall with the
collected and recycled through
the landfill in a to
the operation of an trick-
ling filter.
system illustrated In Figure 1 con-
sisted of four 3-ft-dianeter
containing 10 ft of solid
covered with 2.5 ft of soil
with a The
equipped to interception
of Incident rainfall collection
analysis of
in characteristics of the solid
wastes, gas,
Girer an experimental period of 5 yr»
on premise that
acceptability of ultimate of
accumulations into re-
ceptor, after leachate recycle
attenuated leachate constituents
to residual concentrations, would lie
functions of environmental and/or
regulatory requirements» leachate
recycle compleaented by
separate physical-chemical and biolo-
gical investiga-
tions, ion and
actii'ated carbon slurry systems were
as logical alternatives for
physical-chemical treatment,
pletely nixed, continuous flow re-
actor systems (Figure 2} but
solids recycle for
aerobic and biological
treatability
AND
OF
The four s initiated landfill
colunns constructed In two
phases. Phase I included operation
of two fills (fills 1 and 2) for
a period of 1063 days; phase II
Included operation of two fills
(fills 3 4} concurrently with
747 days of the phase !
studies. The fills of phase I
differed in that fill 1 was con-
structed to permit collection of
without recycle; fill 2
leachate collection with
recycle. Sinilarly, the two fills
of II provided for leachate
collection recycle but also
Initial pH control by neutralization
with and, in fill
4, addition of sludge
for initial nutrient
supplementation,
n ''
. Jj J
f--=-^
'*" 'J
f- -fj
4
-------
All columns were filled with
coarsely ground test material chosen
to simulate domestic solid wastes
(Table 1). The material was manually
compacted to a dry density of about
535 Ib/cu yd. To allow for the
immediate production of leachate
(an experimental expediency), about
250 gal of tap water was added to
each fill; primary sewage sludge
replaced 30 gal of the tap water
in fill 4.
The leachate accumulated as
a consequence of rainfall was removed
from the collection dumps, subjected
to analysis, and then, for the
control fill (fill 1) discarded;
for fills 2, 3 and 4, it was analyzed
and then intermittently pumped back
through the distributor buried
between the top of the solid wastes
and the soil cover for the fills
with leachate recycle. Automatic
pH control was provided for the
phase II fills until pH control
was no longer required. An apparatus
for collecting gas during phase
II was also devised to provide
information on gas evolution and
quality.
Selected analytical data
accumulated during the leachate
recycle studies have been summarized
and graphically displayed in Figures
3 and 4. Recognizing that those
parameters commonly employed to
measure pollutional potential are
of particular importance in the
identification of problems associated
with the escape of leachate from
Table 1. COMPOSITION OF SIMULATED
SOLID WASTES
Constituent
Dry weight, %
Paper 50.0
Plastic 3.0
Glass 7.0
Garbage, garden debris 25.0
Rags 5.0
Stone, sand 5.0
Metal 4.0
Wood 1.0
Total 100.0
landfill operations, BODc has been
used herein to reflect the potential
pollution derived from the decom-
position of organic matter. As
indicated in Figure 3, the control
fill reached high BODs concentrations
and then slowly decreased in concen-
tration with time, whereas the BODc
in the leachate from the fills with
recycle rapidly decreased in
concentration to much lower values.
The rapid decline in BODc with
time in the leachates from the fills
with recycle was considered indi-
cative of an initial acceleration
of biological stabilization of the
more readily available organics
in the solid wastes with the addition
of moisture and/or sludge. The
recycle of leachate maintained an
opportunity for continuous biological
decomposition of the solid waste
constituents, as well as those
transferred to the leachate, whereas
such biological action in the control
fill was curtailed by the addition
of moisture only during periods
of rainfall and by the single-pass
operation. Moreover, recycle with
pH control permitted even greater
rates of stabilization although
sludge seeding initially appeared
not as effective in improving
leachate quality. This was con-
sidered due presumably to the
conflict between pH control, which
would abet anaerobic methane fermen-
tation, and primary sludge seeding,
which would and apparently did
create an environment more beneficial
to volatile acid forming organisms
and therefore unfavorable to the
methane formers because of reductions
in pH. However, continued control
of the pH at neutral and favorable
methane fermentation eventually
nullified the effect of excess
volatile acid production in fill
4 and permitted an extent of
stabilization similar to that
achieved in the other recycle fills.
Similar data on COD and TOC con-
firming the results observed for
BODc, are presented elsewhere(3).
Since solid waste stabilization
as achieved during landfill disposal
is largely dependent on anaerobic
activity, it is possible to further
161
-------
G—n
c—o
CONTROL
LEACHATE RECYCLE
LEACHATE RECYCLE AND pH ADJUSTMENT
LEACHATE RECYCLE, pH ADJUSTMENT AND
INITIAL SLUDGE ADDITION
60 120
180 240 300 360 420
TIME SINCE LEACHATE PRODUCTION BEGAN,days
780 840 900 960 1020 1080 1140
Figure 3. Biochemical oxygen demand of leachate.
interpret the observed changes in
pollutional strength of the leachate
from the fills with recycle. If
the two-phase process of acid
fermentation with the production
of volatile acids followed by
fermentation of these acids to
methane and carbon dioxide is
considered applicable, then the
changes in pollutional charac-
teristics should also be paralleled
by an appearance and subsequent
utilization of volatile acids.
Inspection of Figure 4 indicates
that this was the case. An initial
rise in volatile acids was followed
by their virtual elimination in
the leachate from the fills with
recycle, and elimination at a lesser
and deferred rate in the control
fill without recycle. Based on
other data (3), decreases in volatile
acids tended to proceed in a
sequential pattern from higher to
lower homologues, and gas composition
analysis confirmed their conversion
to methane and carbon dioxide.
As could be expected, the pH
decreased with an increase in
volatile acid concentrations in
the leachate of those fills without
pH control until the acids began
to be utilized. This suggested
that the normal bicarbonate buffer
established near neutral pH was
initially replaced by that
characteristic of the volatile acids
(pk* 4.5) and then was reinstated
for the fill with leachate recycle
as the volatile acids became less
influential. In contrast with fill
2, the control fill did not exhibit
a similar recovery although a gradual
increase in pH was noted. The
initial addition of caustic soda
to the two fills with leachate
recycle (fills 3 and 4) achieved
162
-------
CONTROL
LEACHATE RECYCLE
LEACHATE RECYCLE AND pH ADJUSTMENT
LEACHATE RECYCLE, pH ADJUSTMENT AND
INITIAL SLUDGE ADDITION
60 120 180 240 300 360 420 480 540 600 720
840
960
1080
TIME SINCE LEACHATE PRODUCTION BEGAN, days
Figure 4. pH and total volatile acid concentration of leachate.
a similar acceleration in conversion
of the volatile acids«
Separate Biological Treatment
The leachate used in both the
anaerobic and aerobic biological
treatment studies was a mixture
of leachate accumulated in fill
\ and from a local landfill. The
characteristics of the two leachate
samples are indicated in Table 2.
The pertinent results of these
Studies, although discussed in more
detail elsewhere (3), have been
summarized and included in Figures
5 and 6. The data indicate good
removals of the pollutional
components of the leachate as
measured by COD, BOD5 , TOC, or
volatile acids with an acceptable
correlation between these parameters,
Application of continuous culture
theory analysis yielded the kinetic
parameters indicated, with washout
1 9000
8
LEGEND;
O - O CHEMICAL OXYGEN DEMAND
• - • 5. DAY BIOCHEMICAL OXVOEN DEMAND
A - A TOTAL VOLATILE ACIDS
O - O VOLATILE SUSPENDED SOLIDS
KINETIC PARAMETERS:
* 1.1
"'
= 0.179 «•»"'
= 232 ing BOD,/ 1
» 0.25 m« vss/mg MO, RmovM
= 1-» "«lrt
1800 £
2 34 5 t 7 1(1011121314
LIQUID RETENTION TIME, dly>
Figure S. Anaerobic biological
treatment of leachate
in continuous culture.
163
-------
LEGEND:
5-DAY BIOCHEMICAL OXYGEN DEMAND
CHEMICAL OXYGEN DEMAND
TO1AL OHOANIC CAWON
roiM SUSPENDED SOLIDS
VOLATILE SUSPENDED SOLIDS
KINETIC PARAMETERS^
(Jmo, • 0.46 hour'1
O.QU hour"1
41.3 mgBODj / I
0.5 mg vss/mg BOOj removed
l.B hours
0 I 1 3.45 6
LIQUID RETENTION TIME, hours
Figure 6. Aerobic biological
treatment of
leachate in
continuous culture.
occur ing at 1.3 days and 1.8 hr
for the anaerobic and aerobic
studies, respectively--a reflection
of the relative differences in
generation times between the
anaerobic and aerobic organisms.
Similarly, biological solids yield
for the anaerobic system was half
of the corresponding yield for the
aerobic system--a consequence of
less conversion of substrate to
biomass in the former process.
Once active anaerobic decomposition
had been established, gas yields
ranged between 9 and 17.4 cu £t/lb
BODr destroyed with a methane content
of 70 to 80%. Although this
concentration was higher than
normally reported for anaerobic
conversion processes, even at lower
(60% to 70%) methane contents,
energy recovery during anaerobic
leachate stabilization would be
an interesting possibility.
Separate Treatment of Leachate
Residuafs"
Since inspection of the effluent
quality data from the leachate
recycle and/or separate biological
Table 2. CHARACTERISTICS OF LEACHATE USED DURING SEPARATE
BIOLOGICAL TREATMENT
Leachate
characteristic
pH
COD, mg/t
BOD5, mg/t
TOC, mg/t
Suspended solids
Total, mg/t
Volatile, mg/t
Calcium, mg/t
Magnesium, mg/t
Potassium, mg/t
Sodium, mg/t
Phosphate, mg/t PO^
Total volatile acids,
mg/t as acetic acid
Anaerobic
treatment
5.1
6,000
3,700
2,100
9
1,100
300
200
64
348
313
—
2,700
Aerobic
treatment
7.0
500
260
320
625
160
100
35
204
425
0.7
410
164
-------
treatability studies indicated
organic and inorganic residuals
that could be unacceptable for
ultimate discharge, physical-chemical
processes including ion exchange
and carbon adsorption were applied.
As illustrated in Figure 7, effluent
from the separate aerobic biological
leachate treatment studies was
successfully treated with the
indicated cation exchange resin.
Of those cations measured, excellent
removals were achieved with the
divalent calcium and magnesium
preceeding the removal of the
monovalent sodium and potassium.
With mixed resin ion exchange
(Figure 8), effluent from the aerobic
leachate treatment studies was also
successfully treated for removal
of both cations and anions. The
data indicated that all measured
ionic impurities were capable of
removal again in order of resin
selectivity. Because of the opposite
influences of the resin reactions,
pH and alkalinity or acidity changes
30
LEGEND: o o Ci
A 4 Mg
n o K
• • N«
RESIN: OOWEX SOW, H+ FORM
EXPOSURE TIME: ONE HOUR
-|300
200
468
RESIN DOSAGE, g/l
iso i
1
12 28
Figure 7. Removal of cations
from aerobic
biological treatment
effluent by cation
exchange.
0
200i
O OpH
ALKALINITY
C.
Mg
K
Nl
CI
R«»ms DOWEX 50 W. H+ FORM
OOWEX 1, OH' FORM
Exposure Tim.: ONE HOUR
« I
248
RESIN DOSAGE, 9/1
12 25
Figure 8. Mixed resin ion
exchange treatment
of effluent from
aerobic biological
treatment of
leachate.
were not as dramatic with the mixed
resin ion exchange treatment as
with the separate cation exchange
treatment where ion replacement
released hydrogen ions in excess
and lowered the pH with an increase
in acidity to possibly unacceptable
levels (pH 2.5, 470 mg/t acidity).
The impact of such changes would
necessarily be a function of ionic
concentration and degree of treatment
required.
To remove organic residuals,
effluent from the biological leachate
treatment studies was also subjected
to carbon adsorption as illustrated
by the isotherm developed in Figure
9. Again, the quantity of carbon
and degree of treatment required
would be a function of the leachate
character with respect to concen-
tration and types of materials
present. Moreover, since other
data (3) indicated that certain
165
-------
1.00
0.80-
3
I
0.10
ooe
0.01:
INTERCEPT - 0.64
EXPOSURE TIME: O.5 HOURS
Co- 184
jSji 1.78x10
•4 J.57
10 SO 100 500
CICOO RESIDUAL), m«/l
Figure 9. Isotherm of carbon
adsorption on
effluent from
aerobic biological
treatment of
leachate.
inorganics could be leached from
the carbon if residual treatment
with ion exchange and carbon
adsorption was necessary, treatment
should sequence carbon adsorption
followed by ion exchange.
SUMMARY AND CONCLUSIONS
The results of experimental
studies on the treatment of leachate
by recycle and/or separate biological
and physical-chemical methods have
indicated that a combination of
these methods may be necessary to
reduce the pollutional potential
of leachate from solid waste disposal
sites to a concentration acceptable
for ultimate discharge. Recircu-
lation of leachate through a landfill
will promote a more rapid development
of anaerobic activity and methane
fermentation, increase the rate
and predictability of biological
stabilization of the readily
available organic pollutants in
the wastes, dramatically decrease
the time required for stabilization,
and reduce the potential for
environmental impairment. Moreover,
leachate recirculation with pH
control and initial sludge seeding
may further enhance treatment
efficiency so that the time required
for biological stabilization of
the readily available organic
pollutants in the leachate can be
reduced to a matter of months rather
than years, with the opportunity
for controlled final discharge
and/or treatment of residuals as
may be required.
Application of separate
anaerobic and aerobic biological
processes has proven satisfactory
for leachate treatment; residual
organics and inorganics in the
effluent from these processes are
removed well by carbon adsorption
followed by mixed resin ion exchange.
The degree of residual treatment
is predictable and responsive to
whatever effluent requirement may
be imposed.
Based on the concept of leachate
containment, collection, and
treatment (either by recycle through
the landfill and/or by separate
biological and physical-chemical
methods), the landfill of the future
may well be conceived as a controlled
process conducive to accelerated
stabilization, environmental
protection, and rapid realization
of potentials for land reclamation
and ultimate use.
ACKNOWLEDGMENTS
The research reported herein
was supported jointly by the Georgia
Institute of Technology and the
U.S. Environmental Protection Agency,
Research Grant No. R-801397.
166
-------
REFERENCES Landfill Stabilization with
Leachate Recycle and Residual
Treatment," Water-1974, Ameri,
1 Pohland, F. G., and Maye, P. Inst. of Chem. Engr., Symp.
R., "Landfill Stabilization Ser. 145, 71, 308 (1975).
with Leachate Recycle," Proc. 3. Pohlan37 F. G., "Sanitary
3rd Envir. Engrg. and ScTTLandfill Stabilization with
TTSnfT^ Univ. ot Louisville, Leachate Recycle and Residual
389 (T973). Treatment," Final Report to
2. Pohland, F. G., "Sanitary EPA, Grant No. R-801397, 1975.
167
-------
SOLID WASTE DEGRADATION DUE TO SHREDDING AND SLUDGE ADDITION
Robert K. Ham
Department of Civil and Environmental Engineering
University of Wisconsin eeri"g
Madison, Wisconsin
INTRODUCTION
Among more recent methods of
landfilling, the grinding, milling,
or shredding of refuse and the
addition of sewage sludge are
becoming of increasing interest.
The shredding of refuse is
done for a variety of reasons of
which preparation for further
processing, prepartion for long
distance haul or handling, and
preparation for landfilling are
most common. In preparing refuse
for land disposal, several advan-
tages have been cited as justi-
fication for the cost of refuse
shredding. Among the justifications
are to make sites more acceptable
to the public, to provide better
day-to-day operational quality,
especially under adverse weather
conditions, to increase the density
of refuse in pounds per cubic yard
landfill space consumed, to promote
changes in decomposition deemed
desirable for a particular site,
and to reduce cover requirements.
Of special interest with regard
to the purpose of this paper is
the concept of changing the de-
composition processes and, thereby,
the products of decomposition, as
a result of shredding refuse.
Sewage sludge may be added
to the refuse for several reasons.
The iiiost common is to provide
disposal by incorporating it with
refuse in a landfill. An auxiliary
purpose of adding sewage sludge
to refuse however, may be to change
the degradation processes within
n^ J^w^u1' lt is the la"er
point which is of special interest
in this paper.
This paper will draw on an
experimental program at Madison,
Wisconsin, to describe the
decomposition of shredded refuse
in a landfill in comparison with
nrnL unPr°cessed refuse. This
program began in the late 1960's
as a demonstration of the shredding
process which was funded by a U.S.
Environmental Protection Agency
«??£ ^ra.10n grant in cooperation
£ n5S-?lty °f Madis°*. The Heil
LO of Milwaukee, and The University
oi Wisconsin. One study initiated
under this grant has been continued
ofr PurP°ses °f additional monitoring
r if Composition of test refuse
ceils. The incorporation of sewage
sludge in the landfills will be
illustrated by descriptions of three
oiornr-USinfi different methods of
operating such a landfill and then
by giving some general statements
n,,t /ut!?ting Pr°gram carried
°U* at Nadison, Wisconsin, under
the combined efforts of the Madison
th^r??111^ Sewerage District,
the City of Madison, and The
University of Wisconsin.
DECOMPOSITION OF SHREDDED REFUSE
The decomposition studies to
be described are termed the Lysimeter
168
-------
Studies. The first 2 yr of
monitoring have been described
previously (1). The lysimeters
are each 30x60 ft in surface area.
Six lysimeters, hereafter to be
referred to as cells, were 4 ft
deep and had 100 tons of refuse
each. Two additional cells were
10 ft deep and had 215 tons of
refuse each. All cells were
constructed below grade and had
vertical walls, of which three
walls were made of cement and a
fourth of wood. The bottoms of
these cells were graded to carry
leachate to a central collection
reservoir. The bottom of each cell
consisted of a bituminous layer
covered with plastic that was then
overlaid with crushed rock as a
leachate carrying layer. Cell
surfaces were sloped at a nominal
3$ to one side where runoff was
collected by a gutter arrangement
for volume measurement.
Each set of cells was con-
structed simultaneously with
residential and light commercial
Defuse to ensure equal composition.
when cover was required, the cover
Was silty sand, commonly used for
cover in the Madison area. The
refuse was placed and compacted
Wlth regular sanitary landfill
machinery and experienced operators
were brought for this purpose from
the city's sanitary landfill site.
The first four cells were con-
structed in September 1970, and
CeHs 5 through 8 were constructed
ln October 1972. The cells were
Umbered as follows:
cell 1, unprocessed, covered
immediately;
cell 2, shredded, covered
immediately;
cell 3, shredded, covered after
6 months;
cell 4, shredded, not covered;
cell 5, unprocessed, covered
with shredded refuse (66 tons
unprocessed and 30 tons
shredded);
cell 6, unprocessed, not
covered;
cell 7, 10 ft deep, shredded,
not covered;
cell 8, 10 ft deep, unprocessed,
covered immediately.
Data include precipitation, leachate,
and runoff quantity; leachate qual-
ity; gas composition; temperature;
and settlement. Results from cells
1 through 4 will be presented in
some detail in this paper, whereas
the results from cells 5 through
8 will be presented qualitatively
only. This is because the latter
four cells have not reached a stable
state of decomposition.
RESULTS AND DISCUSSION
The runoff data for the first
four cells are given in Figure 1.
It is noted that the covered cells,
1 and 2, produced approximately
the same curves for the entire
monitoring period. Cell 3 had about
the same curve as 1 and 2 once it
was covered. This cell was covered
after 6 months, as indicated in
the figure by stars. Cell 4 had
no runoff for the first year, with
increasing amounts of runoff since
that time as the surface degraded
to a soil-like surface.
Figure 2 summarizes the leachate
volume data. All cells show a
general increase in leachate volume
with time, corresponding to generally
wetter conditions in the latter
half of 1972 and especially in 1973.
Cells 1 and 2 compare throughout
the reporting period, joined by
cell 3 once it was covered. The
starred points on cell 1 and 2
curves represent unnaturally large
amounts of leachate caused by heavy
rainfall and attendant physical
damage to cell surfaces and runoff
monitoring systems. The monitoring
systems were extensively reworked
during and after this period, and
subsequent points are correct.
The starred points should be dis-
counted. Cell 4 produces slightly
169
-------
100 "I
« 1
I- . I
mm I
Figure 1. Runoff volume for each
cell.
Figure 2. Leachate ¥oluiae for
cell.
170
-------
increasing leachate volumes with
time. This was also in response
to the weather conditions prevailing
in 1972 and 1973.
The water budget over the first
4 1/2 yr of monitoring (excluding
the period of cell damage) is
summarized in Table 1 below. The
conclusions to be reached from the
water budget data are as follows:
The effect of cover was to promote
runoff, but the absence of cover
promoted evapotranspiration. The
net result was that the amount of
leachate was approximately the same
for all four cells whether the
refuse was covered or not. It can
also be concluded that the cells
became more alike with time as the
uncovered cell surface degraded
to a rather soil-like consistency,
and as all cells became covered
with volunteer vegetation and so
became more alike with time.
The COD concentration data
are summarized in Figure 3. Note
the distinct differences between
the curve shapes of cells 1 and
4. Cell 1 produced COD con-
centrations which neither rose nor
fell for 3 yr but, instead,
fluctuated approximately 6,000 ppm
according to weather conditions.
In contrast, cell 4 produced a peak
COD of 30,000 ppm but, after a few
months, became relatively inactive
with respect to COD concentration.
This occurred after approximately
10 months of decomposition. Except
for a second summer rise, the COD's
remained at well under 1,000 ppm
for the final years of monitoring
of this cell. The cell 2 curve
is of the general shape of the cell
1 curve, but fluctuated at much
higher COD levels. By comparing
cells 1, 2, and 4, it can be
concluded that the effect of
shredding was to increase the
concentration of COD approximately
twofold, whereas the effect of
covering was to prolong the period
over which the COD concentrations
remained at these levels. Cell
3 exhibited a curve generally of
the same shape as cell 4 except
for the tendency of this cell to
produce COD concentrations
substantially higher than those
of cell 4 in the latter portion
of the monitoring period.
The specific conductance data
for the four cells are summarized
in Figure 4. The curves are
approximately the same shapes as
were the COD curves for the
respective cells, and the same
general conclusions hold. This
also applies to other specific
chemical analyses not shown here.
The pH curve shapes generally
were the inverse of the COD and
specific conductivity curves, as
shown in Figure 5,
Table 1. WATER BUDGET FOR PERIOD SEPTEMBER 1970 TO FEBRUARY 22, 1975*
Cell
I Runoff
Leachate
Evapotranspirationt
1
2
3
4
7.7
8.5
7.5
2.2
20.7
22.8
19.4
20.4
7106
68.7
73.1
77.4
*Excluding March 6 to May 28, 1973. Total precipitation for this period:
540,000 liters per cell.
tBy difference.
171
-------
»* mffl
^
tf
I
fW\
/ f < >
/VA A--
v
j-j ii;iiri
figure 5, COD,
Figure 4, Leachate specific
««ctance.
172
-------
HO, 4
'•« >
- ••*"*, /"w_
:!\A..rv
not
H tj. ri~TTT-rTTTTTTl-rTTTTTTTTTTTT7'TTTTTTTTT-TTTTrrTTT
<
5. pH.
Thus, cell 1 produced a generally
low pll ieachatc, where the pSl rose
very slowly over the period of
monitoring to levels near neutrality
In contrast, ceil 4 had acidic pH
levels for the first 8 to 9 months,
after which the pH rose rapidly
to neutrality continued at that
I'.vel. In comparing cells 11 2 »
aiid 4, it Is apparent that the
effect of shredding was to lower
the acidic pH levels attained,,
whereas the effect of cover was
to prolong the period of acidic
pli production.
The cumulative production of
COD, in kilograms, for the period
September 1970 to February 22, 1975.,
excluding the period of cell
was: Cell 1, 478.9; cell 2,
cell 3, 680,8; cell 4, 417.4, It
is observed that cell 4 has produced
the least amount of COD over the
noiutoTiJif period^ followed in order
by ceil 1, cell 3, and finally ceil
2a It is apparent that the covering
of shredded refuse was detrimental
as as COD production was
since cell 2 produced
twice the total amount of COD-
substances in leachute
period of Rorutoniif, tn
comparison vith the pfoauct, iojt of
the uncovered cell 4, Cell >,
covered after 6 months, also produced
r.ore Cub than did cell 4; in cell
3, this difference i^ largely the
result of the larfc anomtt of CO'1-
nattfialf- rt-le-iun! during
immediately followini; coverine
operations on thl> cell*
The gas composition data art-
given in Figure t», where- the ga*
composition is pre-^enti-d on a volume
percent basis. It is observed that
production occurred nore
quickly with the shredded iefusr
cells and, in particular, with the
shredded refuse cells that uere
covered immediately. Virtually
no methane i*as; produced in cell
1 evt-n though oxypen level4*, were
generally very low. Ihe production
of methane was observed to generally
decrease in response to periodic
increases lit oxygen, Oxvgen v».is
apparently tarried into cells
175
-------
6AS AT 411
!%
,1 f] f
f-U r-;^
H * w *'
m 1
Figure 6. composition data.
by infiltration or by decreased
biological activity to
temperature or other changes. The
differences in levels between
the covered unco¥ert'd shredded
cells arc in part to the ease
of transmission of methane out of
and atmospheric gases into the cells
that were not covered.
Conclusions to be
ioachatc quality from the first
four colls are that shredding refuse
promotes decomposition (resulting
in rapid use
production) stabilization of
ieachate contaminant production.
Cover prolonged the period of acidic
leachate production and, hence,
postponed methane production. Cover
also seemed to postpone leachate
quality improvements, possibly
to unfavorable forming
condition present in cells,'*
As stated earlier, the results
cells 5 through 8 not yet
complete, but preliminary
conclusions be given regarding
the obtained thus far. The
degradation curves were generally
of the shapes for the
unprocessed-covered-
with-shredded-refusc ccJJs,
generally the
as for cell 4.
Serious problens were associated
with cells 5 6, both of which
unprocessed refuse. In both
cells experienced odor,
fly, rodent problems, cell
6, in particular, visually-
unacceptable. It is apparent
the of shredded refuse as cover
is
this study could not be
for experimental
purposes. It is entirely possible
of carefully controlled
monitored applications of greater
of shredded refuse a,-;
COYGT prove acceptable, but
this fron observations
of other landfills where shredded
refuse is as cover. It Is
apparent that serious problems may
result.
The cells (numbers ^
8) produced higher leachate concen-
174
-------
trations and arc taking substantially
more time to stabilize than the
comparable 4-ft-deep cells.
Additional work needs to be done
on the effect of depth on refuse
decomposition. Thus far, this study
indicates that deeper refuse cells
will result in increase in both
the concentration and time over
which highly contaminated leachates
will be produced.
SEWAGE SLUDGE ADDITION
Among the reasons cited for
adding sewage sludge to refuse are
reasons associated with promoting
decomposition of refuse. In
particular, proponents of this
system believe that the use of
aerobic decomposition results in
more rapid refuse stabilization.
Once the refuse becomes stabilized,
the potential for gas and leachate
contaminant production is lowered,
and compaction results in greater
effective densities,, Effective
density means tons of refuse as
received per cubic yard of landfill
space consumed. In addition to
promoting more rapid decomposition,
sewage sludge is said to promote
the production of heat, which may
increase the rate of evaporation
and, so, lower leachate production.
Once heat is produced, an air cir-
culation pattern will develop over
the refuse that may aid continuing
aerobic decomposition. Finally,
the production of heat may aid the
inactivation of pathogens.
Three examples of the use of
this concept will be given. The
first such example is at Giessen
in West Germany where sewage sludge
is added to refuse on the feeding
conveyor to a Hazemag hammerraill.
The refuse is coarsely shredded
and then placed on an aerobic windrow
area for 6 months. After turning
once, the refuse is landfilled
without cover at a separate site.
The objective in this operation
is to provide sewage sludge disposal,
reduce landfill volume requirements,
and inactivate pathogens (2).
At Odensc, Denmark, a sinilar
process is in use. Refuse is
shredded and sewage sludge is added
on the shredded refuse takeaway
conveyor. The nongrindable fraction,
ballistically separated in the
hammermill, is removed separately.
The refuse-sludge mixture is placed
on the landfill in windrows for
3 to 6 months. After the refuse
has stabilized, the material is
compacted and new windrows are
placed over the area. The objective
in this process is to limit the
production of leachate, promote
refuse stabilization, and increase
the density of refuse in the
landfill. This operation follows
quite closely the concepts tested
at the Kovik tip near Stockholm
(3).
The third example is at Uttigcn,
Switzerland. The landfill is
operated after the concepts of
Professor Pircau of Berlin, who
advocates aerobic landfilling to
achieve greater density and limit
leachate production. In this
example, the refuse is not shredded
and little or no sewage sludge is
added. The concept is said to be
applicable to the addition of sewage
sludge. The refuse is placed in
windrows for 3 to 6 months and
covered with a foam material that
is said to improve the site
esthetically, limit (to some degree)
rodent and fly infestation, and,
in particular, promote evaporation
of rainfall by holding rainfall
at the surface of the landfill.
After decomposition has more or
less been completed, the refuse
is compacted and a new windrow is
built over the sane area.
The examples cited above are
only three of many similar operations
in European countries. Because
of the literature and the potential
value of such methods of landfilling,
a study was undertaken at Madison
(Wisconsin) in cooperation with
the Metropolitan Sewerage District,
which has a sludge disposal problem,
and the City of Madison, which has
the shredded refuse. The study
was modelled after the Kovick tip
175
-------
work, cited above. Twelve cells
were constructed. The top of each
cell xvas 20 by 20 ft in area.
Leachate was collected from a 7-
by 7-ft area with an underdrain
system. The experimental results
verified the design in that there
was sufficient refuse around the
leachate collection area that little
or no edge effects were found to
influence the data. Refuse was
shredded and mixed with various
amounts of sludge on a flat
bituminous area with a front-end
loader. The variables were as
follows: depth, 3 ft or 6 ft;
compaction, none or compacted; and
sludge added, ranging from none
to enough sludge to reach 50%
moisture content, to enough sludge
to reach 70% moisture content.
The 70% moisture content figure
is at or near field capacity.
The study is not yet complete,
but some preliminary conclusions
may be given (4,5)0 It was observed
that the 70% water mixture was not
workable during construction and
could not be condoned for landfill
purposes. Odors were observed,
and perhaps even at the 55% water
level, a sludge-refuse mixture would
have sufficient odors to be of great
concern. Flies were attracted to,
and apparently hatched from, the
refuse sludge cells. No flies were
observed on the cells with no sludge.
It was also observed that rodent
activity developed on the non
compacted cells. Little to no
rodent activity was experienced
on the compacted cells. It was
of interest that good temperature
development occurred even when the
3-ft cells received an additional
3-ft layer of refuse in February
under extremely cold weather
conditions. The production of
leachate per ton of dry refuse
increased markedly with initial
percent water and was not a strong
function of compaction or depth.
Preliminary conclusions from
this work suggest that one must
be very careful in incorporating
sewage sludge with refuse for
landfill purposes. It may be that
environmental and operational
problems will be of great importance
and could easily negate any
advantages that could be obtained
otherwise.
ACKNOWLEDGMENTS
The lysimeter portion of this
paper was supported by the U.S.
Environmental Protection Agency,
and the sewage sludge addition to
milled refuse study was supported
by The City of Madison and the
Madison Metropolitan Sewerage
District.
REFERENCES
1. Anderson, C. R., and R. K,
Ham, "Lysimeter Studies of
the Decomposition of Refuse,"
Part I, Waste Age 5 (9):33,
Dec. 1974; Part II, Waste Age
6:(1):30, Jan. 1975; Part III,
Waste Age 6(2):38, Feb 1975.
2. Gotze, K., M. Budig, and E.
Homrighausen, "The Giessen
Model--Simultaneous Disposal
of Solid and Liquid Wastes,"
Der Stadtetag, Vols. 4 and
5, 1969.
3. Yhland, E., and H. Karlsson,
"Open Refuse Composting—Trials
at the Kovik Tip 1970-71,"
A. Z. Sellbergs AB, Stockholm,
Sweden, Nov. 1971.
4. Pickart, B. J., "Landfilling
Milled Refuse Mixed with
Digested Sewage Sludge," M.S.
thesis, Civil and Environmental
Engineering Department, The
University of Wisconsin-Madison,
1974.
5. Boley, H. L., personal communi-
cation, 1975.
176
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CASE HISTORY OF LANDFILL GAS MOVEMENT THROUGH SOILS
Franklin B. Flower
Cook College, Rutgers University
New Brunswick, New Jersey
This afternoon I an going to
briefly describe three New Jersey
underground landfill gas migration
problems with which the Mew Jersey
Cooperative Extension Service has
been involved during the last half
dozen years.
The New Jersey Cooperative
Extension Service is charged with
the responsibility of responding
directly to the needs of the state's
citizens; therefore, it becomes
involved with various kinds of
problems. One of these has been
the underground generation and
movement of combustible gases,
carbon dioxide, and the odorous
gases of sulfur reduction. Although
there can be nany different sources
for these gases, those we have found
that migrate the greatest distance
laterally underground have arisen
from the decomposition of organic
matter in commercial refuse landfills
located in old sand and gravel pits.
It is our investigations into three
of these problems that I will briefly
describe this afternoon.
The members of the Rutgers
Cooperative Extension Service
faculty, who have been involved
in these studies, include not only
me, a specialist in environmental
sciences, but also county agents,
plant pathologists, entomologists,
and soil scientists. In addition,
whenever possible, we have involved
the staffs of the state, county,
and municipal health departments,
the Mew Jersey Bureau of Solid Waste
Management, the Federal Office of
Solid Waste Management Programs,
and the owners and operators of
the various refuse landfills.
All three of these landfill
gas migration problems were first
brought to my attention by the
respective county agents. After
they, with the assistance of various
specialists from Cook College, were
unable to identify the cause of
vegetation death, they asked me
to look at the situation because
I was listed as a refuse specialist
and they knew that refuse was buried
in extensive quantities not too
far from the sites of the vegetation
death.
The problems to be described
include the death of peach trees
in a commercial peach orchard in
Gloucester County, the death of
ornamental vegetation in Camden
County, and the demise of commercial
farm crops in Burlington County.
In addition to the death of vegeta-
tion, the Camden County case involved
a hazard to life and property because
of the entrance of combustible gases
into private residences adjacent
to the landfill. However, even
here, it was vegetation death that
first brought the problem to our
attention.
GAS MEASUREMENTS
All of our underground gas
measurements were made in the field.
For this purpose, we have adapted
for our needs various gas measuring
equipment that was originally
177
-------
designed for making safety checks
and measuring combustion effi-
ciencies.
To determine whether or not
foreign gases are present in the
soil atmospheres, it is necessary
in most cases to first make a hole
in the ground. When we began these
studies in 1969, we made these holes
with a post-hole digger. After
completing the hole, we covered it
with a large garbage can lid and
let the pround gas atmospheres
"flow" for a specific time period
into the hole from which we'later
drew our gas samples. This was a
very tine and energy consuming
r
,**•
it > . *' V ' •
, •> />#,'.• >V", ."''%.*
• •*•«*••• '>,->, .*/ ' _»;.,'
&••:••
•',„," ' ,> ' t"n •*«,.-"'; *
Figure 1. Usinjj «Pogo Stick' (bar
hole maker) to make a
ground gas sampling hole,
,'•«
'•I Ai~.
M
•>'!*
Figure 2. Withdrawing a ground gas
sample through an Explo-
simeter.
process. Later we drove a 1-in.-
diameter steel rod into the ground
with a sledge hammer and then sampled
the ground gases directly from this
bar hole. Finally, we have cone
to use a commercial bar hole maker
to obtain a 3-ft-deep, 1/2-in.-
diameter hole in the ground. This
commercial instrument (Figure 1}
incorporates the steel hole-making
rod and driving weight into one
convenient unit. This same type
of unit is used by most gas utility
companies when searching for leaks
from their underground pipes. The
handle of this bar hole naker is
electrically insulated for safety
to prevent a shock should you corae
in contact with a live underground
electric wire.
The most convenient test (Figure
2) to make in checking for gases'of
178
-------
anaerobic decomposition of organic
matter Is for combustible gases
with a combustible gas neter. A
gas sample is drawn from the bar
hole through an M.S.A. Explosineter
(Figure 2), which Is the type of
instrument used by the utility
companies when looking for leaks
in their underground line1;. The
Wheatstone's bridge principle ir.
used within the instruutnt for
determining the concentration of
combustible gase.4 , One ler. of the
bridge consists of a catalytic unit
that burns the combustible gases-
changing its resistance » thereby
unbalancing the bridge and giving
a reading on the galvanometer (Figure
5}. The sample is withdrawn from
the bar hole by of a 3-ft-long
nonsparking probe. If desired,
a nonconducting probe also be
used. A rubber stopper is placed
over the upper end of the sampling
probe to help seal the bar hole
from the ambient air. However,
the nature of the sampling method
frequently incorporates large
quantities of dilution air. These
combustible ga:» f.-iding instruments
indicate percent ot" the lower
explosive limit ,^f the gases for
which the instrument is calibrated.
7h« Jov.t.r i-Ajtlo.,*V', limit for methane
j> a 3,i dilution i!> air, However,
it ij po'j'iiMe to full from the
r< ;j>oii';e of t st 'I'tei whether or
not the coniiu- t il/li- j_'.>.s concen-
tration j * buts-.'ftn th'. lower and
the upper explosive liraits or above
the upper explosive limit (151
methane in air). By the use of
a dilution tube or, the intake side
of the meter, it i •> possible to
theoretically
-------
is available, and the instruction
booklet will inform you as to the
frequency and extent of routine
maintenance.
The carbon dioxide and oxygen
concentrations of the ground gases
obtained from the bar holes are
analyzed by the Orsat method, which
is nornnlly used to measure the
efficiency of fossil-fuel-fired
furnaces. In our field test work,
we use the Bacharach Fyritc carbon
dioxide and oxygen indicators.
In the carbon dioxide indicator,
the carbon dioxide is absorbed in
Figure 4. Close up of Fyrite oxygen
tester showing a reading
o£ about 61.
a potassium hydroxide solution.
In the oxygen indicator, a chromous
chlorine solution is used. Carbon
dioxide indicators arc available
for reading 0 to 201 and 0 to 601
concentrations. The oxypcn
indicators are for deterwining 0
to 21-s concentrations (Figure 4).
Unpleasant ground gas odors
are frequently an indication of
the presence of the gases of
anaerobic decomposition of organic
matter. These odors can be checked
tor by withdrawing a soil sample
fron the ground and snelling the
sample. If the unpleasant odors
of the products of sulfur reduction
are present, you will know it without
having to receive any instructions.
We have occasionally used
industrial hygiene dry tube
indicators to check for the possible
presence of sulfur gases and carbon
monoxide. However, in general we
find the field test for combustible
gases^to be the easiest, quickest,
and simplest to make. Our next
most frequently used field check
is .or carbon dioxide. Normally
we would not expect to record the
presence of combustible gases or
carbon dioxide with these field
test meters if there were not
substantial gaseous productions
of anaerobic decomposition present
in the soil gases.
LANDFILL GAS MIGRATION
The three New Jersey landfill
gas migration cases that we have
followed most extensively during
the past half dozen yearl took place
in Glassboro, Gloucester County;
Cherryjiili, Camden County; and
AJT»in?0n* !u5lin§ton County.
As I mentioned before, all of these
cases were brought to my attention
iL«te JeSpeCtive Rut§e« County
Agent who was responding to
complaints of vegetation Injury
and death from unknown causes/
i i*?See cases were associated
landfills where refuse had
180
-------
been deposited in worked out sand
and gravel pits.
The landfill in Glassboro
covered about 6 acres. The refuse,
which consisted of household and
industrial wastes, demolition
materials, and sewage sludge, was
deposited to a total depth of 10
to 20 ft. A commercial peach orchard
abutted the landfill along about
1000 ft of Its outer periphery.
The balance of the landfill was
adjacent to open scrub vegetation
land that apparently not serving
any commercial, agricultural, or
residential use,
Landfilling at this site began
February 1968. Refuse decoMpositlon
along the northeast line of the
landfill adjacent to the peach
orchard was completed in 1969,
The peach trees nearest this line
began dying during the summer of
1971. I made my first inspection
of this site in September 1972.
By that time, about 80 peach trees
had died (Figure S). Combustible
gases and carbon dioxide were found
along with low oxygen concentrations
in the area of the root zones of
most of these dead peach trees.
Seventy feet was the greatest
distance from the landfill for any
of these dead peach trees.
In March 1974, landfill
were found greater than 80 ft front
the landfill. A total of about
70 peach trees now died. In
the month, the peach farmer
brought the operator of the landfill
(the Borough of Glassboro} into
the Chancery Division of the Superior
Court of New Jersey. After a week
of testiraony, the case was settled
out of court to the plaintiff's
satisfaction,
I examined the landfill
peach orchard last week. The refuse
landfilling is complete. It appears
to have an adequate cover of bank
run soil material (Figure 6). Some
minor landfill settlement is taking
place and causing surface water
puddles to form following rain
storms. More than half of the
mature peach orchards that were
adjaceat to the landfill have been
removed as part of the regular peach
farming procedure. They were
replaced more than a year ago by
new peach trees. However, it was
noted that along the row of trees
nearest the landfill, the young
trees had apparently died and had
to be replaced agaia. by seedlings
last fall or this spring. Apparently
no corrective measures have been
taken to reduce the lateral migration
of these landfill gases from the
landfill. Until lateral migration
of these gases ceases as a result
Figure 5, A 1972 view of Glassboro
peach orchard with dead
trees adjacent to landfill,
Figure 6* A view of completed re-
fuse landfill at Glass-
boro, New Jersey.
181
-------
of corrective measures or the
cessation of their generation by
the hiodcjjradation of the organic
matter, I expect that that the
farmer will continue to experience
the death of peach trees planted
adjacent to the landfill.
This 9- to 10-acre landfill
is surrounded by 28 single family
homes that were constructed prior
to the refuse landfill. Refuse
10 to 60 ft deep has been deposited
in this former sand and gravel pit.
I was informed that when dumping
began in the fall of 1963, only'
bulky wastes and demolition materials
were being deposited. However,
as tine went on, the nature of the
materials being deposited gradually
changed until it was general
municipal refuse and garbage that
were being deposited. Dumping was
completed in 1970. Since then,
Cherry Hill Township has been
expending efforts to turn this
former landfill into a municipal
park. The fill has been placed
in such a manner as to incorporate
aesthetically pleasing hills and
slopes within the park perimeter,
topsoil has been brought in, and
the area seeded.
We were first called to this
area by the Camdcn County Agent
in January 1969 to help determine
the cause of vegetation death in
the backyard of a home at 219 Rhode
Island Avenue, abutting the landfill
(Figure 7). We were told that much
vegetation in their backyard had
recently died, including a spruce
tree, rhododendron, Japanese yew,
azaleas, dogwood trees, flowering
peach trees, Scotch brooms,
Figure 7. A view of backyard of 229 Rhode Island Ave, Cherry Hill, N.J,
182
-------
arborvitae and Douglas fir, as well
as an area of lawn grass. Our
ground gas tests Indicated the
presence of combustible gases,
carbon dioxide, putrid ground odors,
and the lack of oxygen in the soil
gases. Periodic checks were made
of this area, and it was noted that
the vegetation sickness and deaths
seemed to be gradually progressing
from the area of the interface of
the landfill and the backyard towards
the house. In June 1971, a general
inspection with the county agent
o£ the whole area surrounding the
landfill indicated that there were
clumps of dead vegetation at various
points around the total periphery
and the landfill. At this time,
it was recommended that the re-
sponsible governmental officials
do a check of the complete periphery
of the landfill to see if these
landfill gases night be migrating
frost the landfill into other
backyards and toward other homes.
In the late summer and fall of 1971,
landfill gas fires occurred in two
homes adjacent to this former
landfill. Tests of many homes at
this time revealed the presence
of very high concentrations of
combustible gases in the soil beneath
the crawl spaces of a number of
the homes adjacent to the landfill.
Many hone owners were also com-
plaining of unpleasant odors within
various parts of their hones.
Between December 1971 and
January 1973, four different 10-
to 15-ft deep stone-filled trenches
were installed in an effort to
prevent the lateral migration of
landfill gases from the landfill
to the adjacent property (Figure
8). of these trenches were
successful in stopping this
migration; others were not. In
April 1974, the legal case of about
a dozen residents surrounding the
landfill against Cherry Hill
Township, the owner and operator
of the landfill was'heard in the
Chancery Division of the Superior
Court of Nei«f Jersey. After a week
of testimony, the case was settled
out of court. The plaintiffs
received a total of $50,000 in
settlement. In addition, the
«** " >V*T .-,'.*«! >-irv* • •-,.
*r.
J» > -iTW *»l V ^^ ""T**BT*^iVi» i • Li * Jk» W' f|
y^'-fe^^^: '^*'r ^>"
af^
Figure 8. Trap rock fill trench in
place for venting of lateral
migrating gases, Erlton
Landfill-Park, Cherry Hill,
N.J.
township required to vent the
landfill gases from the periphery
of the landfill.
In the fall of 1974, vertical
venting pipes were installed on
the periphery of the landfill (Figure
9}, Many of the vent pipes along
the east periphery of the landfill
had been vandalized. Someone had
taken the large rocks from the gas-
ventirig trenches and used them as
cannon balls to destroy the tops
of the Yents. However, it did not
appear that the efficiency of these
plactic pipes for gas venting had
been decreased by this vandalism.
Mo signs were noted in March of
1975 of the vandals having tried
to ignite the gas coming from the
pipes.
In April 1974, a single maple
tree was planted in the lower
185
-------
Figure 9. Vertical gas venting pipes
on northwest side of Erlton
Landfill-Park, Cherry Hill,
f 1 T
i^f » »J «
elevations of this landfill park.
However, no -,ign of this maple tree
could be found in March 1975. Over
the total park area, only one clunp
of _ naturally seeded tree's was noted.
This was a group of maple trees
that has been growing for a number
of years near the southeast corner
of the landfill. Tests for ground
gas indicated that the gases of
anaerobic decomposition were not
present in the root zone of these
trees.
Examination of the landfill
park last week revealed that a large
number of deciduous and evergreen
trees had been planted over much
of the park area by a landscaper
last fall. These Included sweet
gum, red oak, crab apple, Japanese
poplar, white pine, Scotch pine,
and fir, among others (Figure 10).
No trees were planted on the tops
of the high refuse hills.
°''H
Figure 10. Newly planted trees and
open shed on Erlton
Landfill-Park.
As of March 1975, many of the
evergreen trees appeared brown.
There were also signs of vandalism
of the trees as some had been pulled
from the ground, others had limbs
broken off, and had apparently
been stolen. The holes left after
the trees had been pulled or dug
from the ground appeared to be
rather shallow the soil beneath
them appeared to be very well sealed
since water puddles remained in
them some days after a heavy rain.
It will be interesting to observe
the fate of this newly planted
vegetation. A group from Cook
College, including plant pathol-
ogists, will be examining the tree
plantings in May to an
evaluation of their viability.
During the last half dozen
years the vegetation in the backyard
of the home of 226 Rhode Island
Ave. has continued to die until only
184
-------
f'.1"
„ -*;.'" - • '*i*"'^"'^-< " ;*'** •
Figure 11. A 1975 view of the backyard
of 229 Rhode Island Ave.
adjacent to the former Erl-
ton Landfill. Two newly
planted e¥ergreen trees are
noted in the foreground.
that vegetation near the hone remains
(Figure 11). It will be interesting
to see if the gas vents prevent
further gas instrusion into these
adjacent lands and permit vegetation
to again be grown.
^M£gijl^^
An operating landfill of about
100 acres exists on the northern
side of Union Landing Road in which,
we were informed, refuse has been
placed to depths of 80 ft, A 600-
ft-long road interface exits between
the landfill and the farm on the
southerly side of Union Landing
Road. The distance between the
edge of the farm and the edge of
the landfill is 50 to 60 ft. This
space is occupied by the Union
Landing Road and its right of way.
Figure 12 is a view of Union Landing
Road in Cinnaminson toward the
southwest. The refuse landfill
is on the right and the adversely
affected farm fields arc to the
left of Union Landing Road.
Apparently all sorts of refuse
materials have been accepted by
the landfill, which began operation
about 10 yr ago.
In the summer of 1970, the
farmer experienced difficulty in
growing tomatoes in. his fields
nearest the landfill. During the
spring plowing of 1971, very
unpleasant odors were noted by the
farmer arising from the area of
his field nearest Union Landing
Road, The farmer now knew that
something was ¥cry wrong with the
soil in this field. At that time,
the Burlington County Agent asked
me to examine this field for possible
problems associated with the refuse
landfill. Examination revealed
landfill decomposition gases in
the farm soil atmospheres as far
as 180 ft frora the nearest edge
of the landfill. In the fall'of
1971, landfill gases were discovered
300 ft from the landfill. Since
the spring of 1971, the farmer has
not cultivated the 2 to 3 acres
of his fields nearest Union Landing
Road. The death of vegetation in
the field resulted in erosion of
the surface of the field until a
weed cover crop dcYeloped.
By the fall of 1971, the
landfill operator had recognized
that his landfill was the source
of the farmer's problem, lie then
installed a 600-ft-long, 10-ft-deep,
3-ft-wide, gravel-filled trench
the total length of the interface
between the landfill and the farm.
This did not seem to alleviate the
problem. Apparently the gases
continued to flow from the landfill
beneath the trench into the farm
field.
In the spring of 1972, tests
were made of the quality of the
soils in the area of the farm field
where vegetation was undamaged and
where the vegetation had been killed
by the landfill gases. The nutrient
185
-------
'... ^••VT':"'-.'";';'-*:^
fes
Figure 1*. Looking southwesterly on
Refuse landfill on right
fields on left of road.
Union Landing Rd., Cinnaminson. N.J.
of road and landf ill-gas-affected farm
quality of both soil ureas wi -. lound
to be the same, Ii 'Iirch of !'»'.,
the landfill oj>-i,iLur install "i
4-in.-diameter, -li:,ric vertM.d
^.' >ar,.ifi ii [ jrn f IP I I inr
" 1'T" • ' "it i or. in tc a depth
i '.?,<• re i j j. In \p11 I oi
j^e t-,
Lit,,!, ii L-/ tli
MT« «-,«£ rit n.i.it
d.,' J"r '
i.i t < ni si ft, j rei l
t< i - i. *<- t'i-, inn
t:i' • a* ],j ; i -it i n
i ' *4 „ t'.t-
•ovt i er ij
litC >*1E1
•i/f cuts for
f.irr' r to
.T t I ons to be
111 to alIeviate
problcn. In
far if i noted
I I !',,'
.
in these areas revealed the presence
of combustible gases up to 60u ft
from the nearest edge of the
landfill. It appears that the
venting pipes are not doing the
j°b '•' '• 'i \i">'.-< f( they would although
visuil ( if.Liiation Indicates that
grou;,i! -r-is nut uelng vented to
the ,it;x< i \ <-rc ' .- the pipe. One
suggestion that has been to
improve gas venting is to install
evacuating pumps on the vertical
pipes to withdraw the combustible
gases frora the landfill.
As Indicated above, we found
landfill gases 180 ft from the
landfill In the spring of 1971,
300 ft from the landfill in the
fall of 1971, and 600 ft from the
landfill In December of 1974,
However, the migration of these
gases not been a constant outward
progression. Measurements taken
at a number of other times indicated
that the landfill gases had
apparently retreated towards the
landfill. Their outward progression
seems to be at an uneYen rate
depending upon various factors,
many of which we have incomplete
understanding. Incidentally, the
consultant hired by the landfill
company reports that the degree
of migrating has decreased
with time. Obviously, our data
are in conflict with his. Some
of this disagreement might be due
186
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M*.
t-V
**•!
\^
; •-•• ;,;,?.••
»/Trv"«i----v^Pr.^
^»T Jif'ss^^**^ " * i?j*• / a , * 1' ^Jj" " s r *• * a * ' fc»' '- -™
I
|
»."' K ** ,r*< >•» ' -t*t.^, *<.T*-*-~AJ
r
sni*1" *~ -----
Figure 13. Vertical gas venting pipes
along the Union Landing
Road edge of refuse land-
fill, Cinnaminson, N.J0
to making measurements at different
locations and times.
We will continue to follow
this situation and determine the
ultimate fate of the landfill gases
and vegetation growth in the fields.
Eight to ten acres of the farm field
are now involved in problems of
poor or no vegetation growth due
to the adverse influence of gases
from the landfill located to the
north of the field. It is planned
to have the Cook College Agricultural
Experiment Station's weed specialist
evaluate the weed growth on this
field. Weeds seem to grow on
landfill-gas-loaded soils. We would
like to know if the species are
atypical for the area and soils.
The landfilling directly north
of Union Landing Road is coming
to a close. Completion of the
landfill will involve the filling
of the easterly corner of this
former sand and gravel pit. This
additional filling of the landfill
area will bring the refuse in contact
with the soil along Union Landing
Road for an additional few hundred
feet immediately opposite the Hunter
Farm. This also includes an area
of farm on which a farm house is
located. It is possible that the
refuse will be located against a
soil bank within about 100 ft of
the farm house. This farm house
has a dirt floor cellar which is
used to store various farm crops
during the winter. Therefore, we
have strongly recommended that
permanent gas sampling stations
be set up opposite the landfill
area still to be filled. In addi-
tion to exposing this farm house
to possible infiltration of landfill
gases, another private home and
at least one light industry building
will also be within a couple hundred
feet of the refuse upon completion
of the landfill. Unless adequate
protective measures, such as a gas
barrier and/or adequate vents, are
taken^to prevent the migration of
landfill gases, it is possible that
these buildings may in time become
involved with the entrance of
combustible gases traveling
underground from the landfill.
CONCLUSIONS
After a half dozen years of
periodically surveying landfill
gas migration problems, we have
come to the following tentative
conclusions:
1. Landfill operators can
get themsleves into a lot
of trouble with migrating
landfill gases.
2. Injury and death of
vegetation may be used
as indicators of the
presence of landfill gases
in the surface soil layers.
However, the gases can
travel laterally below
vegtation without injuring
it and appear at the
18?
-------
.,,,;/
'{'^""'z'^, ' '/'"jr', *!_**-"•:"'' ";-'/,';/•> V''„'• *?***>$ ,™1L H
1 -' "3&{ &
^•^^•i^^^i^W^^^fe^'il^Sif
'' ' '"' *"'-•*'••'/,>'• *-,;,",;*•'-•.'•,.•*/'•?;,-xH'A''' ^••' ; i*4';-»ff^frS;f^
''•.".",•'"-"' ..''*''»>'•'.
-:• /:'vr/,.^-',
•^-rM'|,,; •-* iff
•:;:• ,,--•'•• ~"^?>>-*> *. -,. • .;>',:,•,:';-V'VV<-.":.^,'-v:::V- :<> .':--••••;.--•'^te.'-^^ -.'j;->,
Figure 14. Rye planting in farm field adversely affected by landfill gases
600 ft from nearest edge of landfill, Cnmaminson, N.J.
5.
surface at a greater
distance from the landfill.
It may take substantial
time to note the effects
of landfill migration
upon vegetation.
Gases tend to travel
laterally through permeable
soils from refuse landfills.
Old sand gravel pits
are not good places to
place refuse If you want
to pre¥ent lateral
migration. If old sand
and gravel pits used
as refuse landfills, gas
Yents seals should
be placed at the outer
edge prior to refuse
deposition.
6, Sowetijiujs vents prevent
the lateral migration and
sometimes they do not,
ffe still have quite a bit
to learn about effective
gas Yeiiting to prevent
lateral migration.
7, Political and economic
concerns can inhibit
obtaining all the available
accurate information
relative to a problem such
as landfill gas migration
and vegetation death.
The above presents in brief
outline foria, to our best knowledge.
the historical record of three
landfill migrating gas in
Jersey the associated
vegetation death. We would very
much like to know if others
-------
had similar experiences. We are
particularly interested in knowing
if others have experienced vegetation
death associated with refuse landfill
gases. If others have found that
they can plant all kinds of deep-
rooted vegetation over deep landfills
in which uncombusted biodegradable
refuse lias been deposited during
the last 20 years, we would also
like to know about it. Much still
needs to be learned about how to
make vegetation planted over old
landfills grow well. Information
supplied by all concerning their
experiences with landfill gases
will be helpful in developing
adequate protective measures.
189
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TECHNICAL REPORT DATA
(Please read fnUructions on the reverse before completing}
1. REPORT NO.
EPA-600/9-76-004
4. TITLE AND SUBTITLE
GAS AND LEACHATE FROM LANDFILLS:
Formation, Collection, and Treatment
6. PERFORMING ORGANIZATION CODE
3. RECIPIENT'S ACCESSION>NO.
5. REPORT DATE
March 1976 (Issuing Datel
7. AUTHOR(S)
Emil J. Genetelli and John Cirello
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Department of Environmental Science
Cook College, Rutgers University
P.O. Box 231
New Brunswick, New Jersey 08903
10. PROGRAM ELEMENT NO.
1DB064 (ROAP 21BFP, Task 014)
11. OOJ*DB«On
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