United States
Environmental Protection
Agency
Hazardous Waste Engineering
Research Laboratory
Cincinnati OH 45268
Research and Development
EPA/600/S2-87/090 Feb 1988
Project Summary
Municipal Landfill Gas Condensate
Jeffrey Briggs
New regulations or air emissions from
municipal landfills may require installing
gas collection systems at landfills. As
landfill gas (LFG) is collected, water
and other vapors in the gas invariably
condense in the system or are purposely
removed in the normal treatment of the
gas. Condensate production can amount
to more than 5000 liters per day con-
sisting of two liquid phases: an aqueous
phase and a hydrocarbon phase. The
management of LFG condensate con-
tinues to be a problem for the solid
waste landfill owner or operator because
options for proper disposal are limited.
Liquid disposal to solid waste landfills is
virtually banned, and current regulations
may identify condensate or one of its
phases as a hazardous waste if it fails
the Toxicity Characteristics Leaching
Procedure (TCLP) Toxicity Test. EPA's
Office of Solid Waste desired a baseline
study to identify physical/chemical
characteristics and hazardous properties
of condensate from LFG collection sys-
tems at solid waste landfills.
This study involved the collection and
analysis of condensate samples from
four U.S. landfill sites with active gas
migration or gas production systems.
The characteristics of both the hydro-
carbon phase and the aqueous phase of
the condensate were compared against
EPA hazardous waste criteria. Results
indicated that neither phase exhibited
properties of corrosivity or reactivity.
However, the hydrocarbon phase was
ignitable, as was the aqueous phase in
one sample. No pesticides, PCBs or
priority pollutant metals were detected
in any sample. A list was developed of
94 organic compounds found in LFG
condensate, 49 of which are priority
pollutant compounds.
Most condensate samples obtained
at the four sites were identified as
hazardous according to the proposed
regulatory limits of the TCLP Toxicity
Test. Eleven compounds were present
in the hydrocarbon phase at concentra-
tions exceeding the proposed limits and
five compounds exceeded the limits in
the aqueous phase. However, the four
sites varied considerably and definite
correlations could not be made between
site characteristics, the LFG collection
systems, and the resultant condensate
properties. It is possible that the low
levels of organics found in the con-
densate from the aerobic LFG control
site may result from the aerobic bio-
degradation of some of the compounds
present. This correlation may be biased
by other factors and should be tested
by collecting data from more sites, both
aerobic and anaerobic.
This Project Summary was developed
by EPA's Hazardous Waste Engineering
Research Laboratory, Cincinnati, OH, to
announce key findings of the research
project that Is fully documented In a
separate report of the same title (see
Project Report ordering Information at
back).
Introduction
Landfill gas (LFG) condensate is a liquid
produced in landfill gas collection sys-
tems. The condensate is removed as the
LFG is withdrawn from landfills. Produc-
tion of condensate may be through natural
or artificial cooling of the gas or through
physical processes such as volume ex-
pansion. Condensate is composed prin-
cipally of water and organic compounds.
Often the organic compounds are not
soluble in water and the condensate
separates into a watery (aqueous) phase
and a floating organic (hydrocarbon)
phase. This organic fraction may comprise
up to five percent of the liquid.
The purpose of this project was: (1) to
review existing background information
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on the chracteristics of condensate; and
(2) to obtain and analyze condensate
samples from LFG collection systems at
four landfills nationwide. The condensate
samples were sampled and analyzed
under prescribed conditions in order to
qualitatively and quantitatively describe
condensate characteristics. Specifically,
the analyses were to determine baseline
properties of LFG condensate from a
limited number of samples and establish
if either condensate phase is hazardous,
and if so, on the basis of which con-
stituents. In addition, LFG collection
system information was collected to
assess possible impacts due to system
operations.
Procedure
Landfill sites for condensate sampling
were chosen on the basis of size, geo-
graphic location, and cooperation of the
site owners/operators. The sites chosen
had to be of sufficient size to produce
several hundred gallons of condensate
per day to ensure representative samples
of newly formed condensate. Landfill sites
with either gas control systems or gas
production systems were considered for
selection. Similarly, it was desirable to
consider sites that contained only mu-
nicipal refuse versus those sites that
combined municipal and commercial
waste.
Finally, landfill sites were selected
based on the owners/operators willing-
ness to allow site access and supply
background information on site develop-
ment and operation. Those owners who
agreed to participate, did so with the
understanding that their sites would not
be identified. Four landfill sites were
selected; three of the sites had gas re-
covery systems for processing and ulti-
mate sale for production purposes, and
the other had a collection system for
purposes of methane migration control.
Landfill gas condensate was sampled
from fresh accumulations in closed stor-
age containers or directly from the gas
collection pipelines. All samples were
taken under vacuum from the last point
in the system prior to treatment, pro-
cessing, or blower equipment. This
sampling point was the "knock-out" pot
storage tanks at the production sites and
from a low point in the collection system
pipe at the control system. All samples
were fresh and volatilization of trace
organics was minimized during sampling.
Where possible, condensate samples
were obtained separately for both the
aqueous and hydrocarbon phases.
Analyses of condensate were per-
formed using EPA Standard Methods for
hazardous characteristics, priority pol-
lutant metals (EPA SW-846), priority pol-
lutant organic compounds, (EPA 624 and
625), and pesticides (EPA 608). Con-
ventional wastewater parameters, BOD,
COD, TOC, pH, nitrate nitrogen, and
hydrogen sulfide were also measured
using Standard Methods. (16th Ed., 1985).
Duplicates, spikes and surrogates were
used to determine precision and accuracy
of the analyses. The GC/MS analyses
were performed with a Hewlett Packard
GC/MS 5995* with a HP1000 data sys-
tem using a packed column of 1 percent
SP-1000 on 60/80 carbopack B.
Results and Discussion
There is little published information on
the characteristics and quantities of con-
densate produced in LFG collection sys-
tems. Some owner/operators of these
systems have performed sampling and
analysis of condensate for their own use
but these results remain unpublished.
Data obtained from nine landfills samples
(a total of 24 samples) indicated a large
variability for various parameters. Table 1
compares BOD, COD, and TOC analysis
from 24 condensate (unpublished data)
to typical values from the literature for
sewage and leachate. However, the
sampling and analytical procedures em-
ployed for the unpublished data may not
valid. In addition, results from condensate
sampling under this study from the four
landfills are included in Table 1.
Site information was obtained from the
four landfill sites selected for LFG con-
densate and gas sampling. These sites
are designated as "Northeast," "Mid-
west," "Northern California," and
"Southern California."
The amount of condensate collected
from the four sites varies from about
2,700 to 7,500 liters per day. There was
* Mention of trade names or commercial products
does not constitute endorsement or recommenda-
tion for use.
no apparent correlation between climate
and condensate volume. The warm, dry
Southern California site produces up to
7,500 liters per day from about 85,000
cubic meters of LFG, while the cool,
moist Midwest site produces only about
4,200 liters per day from over 85,000
cubic meters of LFG.
The operating data from each of the
four LFG collection systems were col-
lected at the time of sampling. Data
included gas temperature, composition
(percent methane and oxygen), and
average BTU content. Methane and
oxygen contents varied according to the
type of gas collection system at the site.
At the Northeast site, methane content
was low (22 percent), due to the opera-
tion of the extraction system which allows
air intrusion in order to control gas
migration at the landfill perimeter. At the
remaining three sites with gas production
systems, methane contents ranged from
54 to 63 percent. Gas temperatures were
measured on the inlet side of the vacuum
pumping equipment at each site and
ranged from 17° C at the Northern
California site to 36.7° C at the Northeast
site.
In two of the three production sites,
LFG condensate samples were obtained
as two distinct phases, principally in
aqueous phase and a small volume of
floating organic (hydrocarbon) phase.
Both aqueous and organic phases were
sampled at the two California sites with
the organic phase comprising approxi-
mately 0.5 percent of the condensate
volume. At the Midwest site two phases
were produced but sampling access was
provided only to the aqueous phase by
the site operator. The Northeast site
produced an oily film of insufficient
quantity to analyze separately as the
organic phase.
The samples from the four sites are
compared on the basis of the four stan-
dard EPA hazardous waste characteristics
below:
Ignitablllty
Of six condensate samples analyzed
Table 1. Comparison of BOD, COD, and TOC Values for Condensate, Domestic Sewage and
Landfill Leachate
Landfill Gas Condensate
Parameter
BOD
COD
TOC
Unpublished
data
(mg/l)
1.000-31,250
476 - 14,720
575- 4,900
Data from
this study
(mg/l)
4,000- 17.500
1,042 - 30,500
94 - 23.500
Domestic
sewage
fmg/l)
100- 500
25O - 1.000
100- 300
Typical
leachate
(mg/D
1.050 - 32.400
800-50.700
700 - 68.000
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(four aqueous and two organic), three
were ignitable. The organic phase
samples from the California sites were
ignitable.
CorrosMty and Reactivity
No condensate samples were hazard-
ous on the basis of corrosivity. Con-
densate from the Northeast site was
slightly alkaline (pH 7.6), while the three
production systems produced acidic con-
densate ranging from pH 4.21 to 5.03.
Similarly, no condensate samples were
hazardous on the basis of reactivity.
TCLP Toxlclty Test
EPA has proposed to amend the EP
Toxicity Test replacing the old leaching
procedure with the new Toxicity Char-
acteristics Leaching Procedure1. Part of
this proposal includes expanding the list
of toxic compounds from 14 to 52. The
condensate analytical results were
compared to this proposed list.
Condensate samples were analyzed for
pesticides, PCBs, and priority pollutant
metals and organic compounds. No pesti-
cides, PCBs, or priority pollutant metals
were detected in any samples. The or-
ganic constituents in the condensate
samples were analyzed in three major
groups for each phase sampled (4
aqueous and 2 hydrocarbon): the priority
pollutant volatile organic compounds, the
priority pollutant base/neutral and acid
extractable compounds, and other organic
compounds. These latter compounds were
detected by GC/MS techniques but not
quantified.
A total of 94 organic compounds was
identified as present in LFG condensate,
49 of which are priority pollutant com-
pounds. Eleven of these priority pollutant
compounds were found in every con-
densate sample in either the aqueous or
organic phase: benzene, toluene, phenol,
ethyl benzene, benzyl alcohol, bis (2-
chloroisopropyl) ether, bis (2-ethylhexyl)
phthalate, naphthalene, N-nitrosodi-
methylamine, 2,4-dimethylphenol, and
4-methylphenol. Fifteen compounds
found in the condensate samples are on
the proposed TCLP Toxicity List. These
are listed in Table 2, with their occurrence
in each of the two phases (aqueous and
organic phase) and the proposed regula-
tory level. Eight of the compounds were
found exceeding the proposed regulatory
levels in the organic phase, three in both
the organic and aqueous phases, and
two in only the aqueous phase. In addition
to the compounds on the proposed TCLP
Tabl« 2.
Priority Pollutant Organic Compounds Found In LFG Condensate Exceeding
Regulatory Levels In The TCLP Toxicity List
Presence
Regulatory Regulatory Level
Level* Exceeded
Compound
Volatile Organic Compounds
1. Benzene
2. Toluene
3. Methylene chloride
4. Trichloroethylene
5. 2-Butanone (MEK)
Aqueous
X
X
X
X
X
Organic
X
X
X
X
(mg/liter)
0.07
14.4
86
0.07
72
Aqueous
X
X
Organic
X
X
X
X
6. Chlorobemene X** X 1.4 X
7. Tetrachloroethylene X X 0.1 X X
8. 1,1,1-Trichloroethane X X 30 X
9. Chloroform X" X 0.07 X
10. Carbon tetrachloride X 007 X
Acid and Base/Neutral Compounds
11. Phenol X 14.4
12. 1,2-Dichlorobenzene X X 4.3 X
13. 1,4-Dichlorobenzene X X 10.8 X
14. Nitrobenzene X 0.13
15. Bisf2-chloroisopropy)ether X X 0.05 X X
* Regulatory level according to proposed TCLP Toxicity List'.
** Detected, but at levels too low to reliably quantify.
' Federal Register. Vol. 51, 114, June 13, 1986
Toxicity List, many other organic com-
pounds were detected.
Conclusions and
Recommendations
Conclusions
This investigation obtained and
analyzed condensate samples from
selected nationwide landfill sites with
operating LFG collection systems. Due to
an absence of published literature on
condensate, this work serves as a baseline
effort to identify condensate characteris-
tics. Conclusions and recommendations
from this investigation are based on a
limited sampling program that indicates
that site-specific variability is to be ex-
pected. However, they are presented
below as guidance to landfill owner/
operators, landfill design engineers and
regulatory agencies for implementing
practical measures to collect and properly
dispose LFG condensate.
• Landfill gas condensate is a two-
phase liquid containing an aqueous
phase and an organic phase (which
often separates as a float). The
organic phase varies in volume and
composition among sites, and may
range from less than one percent to
five percent (by volume) of the total
mixture. In general, the aqueous
phase is mostly water and trace
organic compounds. The organic
phase consists principally of hydro-
carbons, xylenes, chloroethanes,
chloroethenes, benzene, toluene,
other priority pollutants, and trace
moisture.
Condensate production from three
sites with LFG recovery systems
ranged from 44 to 162 liters gen-
erated per 1000 cubic meters of
unprocessed LFG.
Condensate wastewater parameters
(e.g., BOD, TOC, COD, etc.) vary
among sites and is similar to typical
landfill leachate.
The major organic components of
LFG condensate were identified
using standard EPA analytical
methods for priority pollutants in
water samples. The frequency of
detection and concentrations are
compared to regulatory levels in the
proposed TCLP Toxicity Test. Of the
49 priority pollutant compounds
detected in condensate, 15 are listed
in the proposed TCLP contaminants,
list. Ten VOCs and three acid and
base/neutral priority pollutants were
found in condensate at levels ex-
ceeding the proposed regulatory
limits.
Condensate quality, as measured by
the organic priority pollutants pre-
sent, differs according to each phase
(i.e., aqueous versus organic) and
the type of priority pollutant (VOCs
versus acid and base/neutral frac-
tions). Similar VOCs are found in
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both the aqueous and organic phases;
however, a larger number of acid
and base/neutral compounds are
present in the aqueous than in the
organic phase of the condensate.
Concentration levels may be orders
of magnitude higher in the organic
phase than the aqueous phase.
• Landfill gas condensate samples
from the four sites contained no
pesticides, PCBs, or priority pollutant
metals and did not exhibit hazardous
characteristics when tested for cor-
rosivity or reactivity.
229 Based on hazardous characteristics
tests for ignitability and TCLP toxicity,
LFG condensate, and particularly the
organic phase, may be a hazardous
waste. Eleven priority pollutants
were detected in the organic phase
at levels that exceed the proposed
regulatory limits.
Recommendations
1. The composition of LFG condensate
is variable and is likely influenced
by many site-specific variables.
Future field testing efforts should
include a sufficient number of
samples at 20 to 30 nationwide
LFG collection sites to help deter-
mine the key environmental and
design variables that affect con-
densate composition.
2. This study was directed principally
towards identifying the priority pol-
lutants present in condensate.
Future analytical efforts should fully
characterize LFG condensate and in
particular, the organic phase, for
other (i.e., nonpriority pollutants)
organic and inorganic constituents.
Analytical problems experienced on
the oil-like organic phase caused by
the complicated matrix suggests the
need for analytical protocol develop-
ment and testing.
Regulatory decisions regarding
whether or not condensate must be
treated and disposed as a hazardous
waste may impact available capacity
for treatment and the economic
viability of gas recovery systems.
Further studies should address the
nature and extent of these impacts.
Jeffrey Briggs is with SCS Engineers, Reston. VA 22090.
Paul de Percin is the EPA Project Officer (see below).
The complete report, entitled "Municipal Landfill Gas Condensate," (Order No.
PB 88-113 246/AS; Cost: $12.95, subject to change) will be available only
from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Hazardous Waste Engineering Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
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EPA
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