United States
Environmental Protection
Agency
National Risk Management
Research Laboratory
Research Triangle Park, NC 27711
Research and Development
EPA/600/SR-98/021 April 1998
Project Summary
Emerging Technologies for the
Management and Utilization of
Landfill Gas
Stephen Roe, Joel Reisman, Randy Strait, and Michiel Doom
The report presents information on
emerging technologies that are con-
sidered to be commercially available
(Tier 1), currently undergoing research
and development (Tier 2), or are con-
sidered as potentially applicable (Tier
3), for the management of landfill gas
(LFG) emissions or for the utilization of
methane (CH4) and carbon dioxide (CO2)
from LFG. Discussion of emerging tech-
nologies is based on information that
was readily available as of September
1997.
The emerging technologies that are
considered to be Tier 1 are 1) phos-
phoric acid fuel cells, 2) processes for
converting CH4 from LFG to com-
pressed LFG for vehicle fuel or other
fuel uses, and (3) use of LFG as a fuel
source for leachate evaporation sys-
tems. The Tier 2 technologies covered
in the report are 1) operation of land-
fills as anaerobic bioreactors, 2) opera-
tion of landfills as aerobic bioreactors,
3) production of methanol from LFG, 4)
production of commercial CO2 from
LFG, and 5) use of LFG to provide fuel
for heat and CO2 enhancement in green-
houses. Tier 3 technologies, consid-
ered as potentially applicable for LFG,
include Stirling and Organic Rankine
Cycle engines. These two technologies
could potentially use waste heat from
flares used to control landfill gases to
generate mechanical energy. However,
they have not yet undergone field dem-
onstration at a landfill to determine if
they would be cost effective.
This Project Summary was developed
by EPA's National Risk Management
Research Laboratory, Research Triangle
Park, NC, to announce key findings of
the research project that is fully docu-
mented in a separate report of the same
title (see Project Report ordering infor-
mation at back).
Introduction
The report presents information on
emerging technologies for utilizing CH4 and
CO2 from LFG. The focus of the report is
on Tier 1 and Tier 2 emerging technolo-
gies for LFG utilization (e.g., as an energy
source, to develop raw materials). Addi-
tional coverage is given to two technolo-
gies that are considered as potentially
applicable for the utilization of LFG: Stirling
and Organic Rankine Cycle engines. The
report is not an exhaustive review of
emerging technologies for the manage-
ment and utilization of LFG but those pro-
cesses that are being demonstrated or
are planned for demonstration. Discus-
sion of the emerging technologies is based
on information that was readily available
as of September 1997.
Information Development and
Presentation
Information for the various management
and utilization technologies was obtained
primarily from the technology developers.
Data contained in recent publications were
also used. Section 1.0 of the report con-
tains an introduction and overview of the
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report including a discussion of incentives
for LFG utilization. Section 2.0 of the re-
port discusses emerging technologies that
are considered to be commercially avail-
able. These Tier 1 technologies that are
undergoing field-scale demonstration in-
clude:
• Phosphoric acid fuel cells for gener-
ating electricity and waste heat;
• Processes for converting CH4 from
LFG to compressed landfill gas (CLG)
for vehicle fuel and other fuel uses;
and
• Use of LFG as a fuel for leachate
evaporation systems.
Section 3.0 of the report describes Tier
2 technologies. Field demonstrations have
been performed for some of these tech-
nologies (e.g., anaerobic and aerobic
bioreactors, use of LFG for fuel to heat
greenhouses and provide CO2 enhance-
ment), while others have undergone only
bench-scale demonstrations (e.g., produc-
tion of methanol or commercial CO2). Sec-
tion 4.0 describes those technologies that
are considered as potentially applicable
for generating energy from waste heat
produced by flares used to control landfill
gases. These technologies include the
Stirling engine and Organic Rankine Cycle
engines.
For the Tier 1 technologies, the report
provides an introduction and general over-
view of the technology, a process descrip-
tion, performance, technical issues
encountered during the project, informa-
tion on the project economics, and emis-
sions and secondary environmental
impacts data. For all of the technologies,
the report provides information on the tech-
nical feasibility, emissions, and econom-
ics of each technology to the extent that
the developers of the technologies were
able to provide such information. The de-
velopment of the technologies is ongoing
and the developers of the technologies
are identified in each section of the report.
An example of process economics infor-
mation contained in the report is presented
in Figure 1 for the economies of scale of
CLG production facilities.
Process descriptions for each LFG utili-
zation technology are provided. Figure 2
is an example flow diagram from the re-
port on a process for converting methane
from LFG to CLG.
Retail CNG
Total
O&M
Capital
Power
Membrane/carbon
5,000
10,000
GGE/day
15,000
20,000
Figure 1. Estimated economies of scale for CLG production facilities
(GGE = gallons of gasoline - equivalent).
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Storage Tanks
WOscfm
3,600 psi
•*-+
H 1
i
fl°
spens
. 96% CH4
3,000 psi
. Waste Gas
150 scfm
28% CH
Stage 5 Łtage_4
Compression Compression
Membranes
520 psi
140°F
Heater
Carbon
Guard
Beds
LFGIn
250 scfm
55% CH.
Condensate
~<
RotaryVane Hegf
Exchanger
Reciprocating Compressors
Figure 2. Flow diagram of the Los Angeles County Sanitation Districts' CLG Production Facility
(1 °F=9/5 °C + 32, 1 ft3/min = 0.0283m3/min, and 1 psi = 6.89kPa).
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Stephen Roe and Joel Reisman are with E.H. Pechan and Associates, Inc., Rancho
Cordova, CA 95742. Randy Strait and Michiel Doom are with E.H. Pechan and Associ-
ates, Inc., Durham, NC 27707.
Susan A. Thorneloe is the EPA Project Officer (see below).
The complete report, entitled "Emerging Technologies for the Management and Utilization
of Landfill Gas," (Order No. PB98-127913 Cost: $27.00, subject to change) will be
available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-605-6000
The EPA Project Officer can be contacted at:
National Risk Management Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
Official Business
Penalty for Private Use
$300
EPA/600/SR-98/021
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