United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park, NC 27711
Research and Development
EPA/600/S8-89/058 Aug. 1990
&EPA Project Summary
Municipal Waste Combustion
Assessment: Combustion
Control at Existing Facilities
P. J. Schindler
The EPA's Office of Air Quality
Planning and Standards (OAQPS) is
developing emission standards and
guidelines for new and existing
municipal waste combustors (MWCs)
under the authority of Sections
111 (b) and 111 (d) of the Clean Air Act
(CAA). The EPA's Office of Research
and Development (ORD) is providing
support in developing the technical
basis for good combustion practice
(GCP), which is included as a
regulatory alternative in the
standards and guidelines. This report
provides the supporting data and
rationale used to establish baseline
emission levels for model plants that
represent portions of the existing
population of MWCs. The baseline
emissions were developed using the
existing MWC data base or, where no
data existed, engineering judgement
The baseline emissions represent
performance levels against which the
effectiveness and costs of emission
control alternatives can be evaluated.
An assessment of potential
combustion retrofit options was
developed and applied to each model
plant, and emission reduction
estimates were made for each retrofit
application. This report provides the
rationale used to estimate the
emission reductions associated with
each combustion retrofit.
This Project Summary was
developed by EPA's Air and Energy
Engineering Research Laboratory,
Research Triangle Park, NC, 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
On July 7, 1987, the U.S. EPA
announced its intent to develop air
emission standards for new municipal
waste combustors (MWCs) and emission
guidelines for existing MWCs, under the
authority of Section 111 of the Clean Air
Act. The New Source Performance
Standard (NSPS) will apply to all MWCs
that commence construction after the
proposal date, and the guidelines will
apply to all MWCs not covered by the
NSPS. Following the July 1987
announcement, an extensive background
information development and data
gathering effort was initiated to provide
the technical support for the proposed
regulations. The NSPS and guidelines
development includes a performance
assessment of emission control
alternatives that are applied to
hypothetical model plants. The models
represent typical classes of MWCs within
the existing and projected population.
Baseline emission estimates are
developed for each model plant, and
various control alternatives are applied to
each model to estimate the potential for
reduction of emissions from baseline
levels. Costs of control alternatives were
estimated to permit calculation of the
cost effectiveness of control options.
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Model Plants
The EPA developed 12 model plants
which represent groups of existing
MWCs that will be regulated by the
emission guidelines. Baseline emissions
were established for each of the models
and retrofit control alternatives were
applied to each model plant. Emission
reductions and costs were estimated, and
the results were documented in an EPA
report which served as one of the main
background documents for the emission
guidelines. This report summarizes the
performance data and supporting
rationale that were used to establish the
baseline emission estimates for twelve
MWC model plants and provides the
rationale for estimating emission
reductions that result from the application
of combustion retrofits to each model
plant. The retrofit options are intended to
modify model plant performance to a
level indicative of good combustion
practice (GCP). GCP, defined and
developed in EPA's Report to Congress
on MWCs, requires that specific design,
operation, control, and monitoring
features be in place to optimize the
combustion process, thus minimizing
emission of organics and carbon
monoxide (CO). This report summarizes
the components of GCP and the design
and operating features of the combustors
in the data base and evaluates the extent
to which recommended design and
operating components of GCP are in
place at each plant.
Twelve model plants were developed
to represent the majority of combustor
classes that would be regulated by the
guidelines. The models included three
mass burn waterwall MWCs, three mass
burn refractory wall MWCs, one rotary
waterwall MWC, one modular excess air
MWC, two modular starved air MWCs,
and two refuse- derived-fuel (RDF) fired
spreader stoker MWCs. Information
provided for each model plant included
unit size, number of combustors per site,
annual operating hours, energy recovery
practices, and fuel type (either
unprocessed municipal solid waste, or
RDF).
Emission Estimates
Baseline uncontrolled emissions
were estimated for five air pollutants:
polychlorinated dibenzo-p-dioxins and
dibenzofurans (CDD/CDF), CO,
particulate matter (PM), hydrogen
chloride (HCI) and sulfur dioxide (S02).
Baseline HCI and S02 emissions were
established based on assumed fuel
chlorine and sulfur contents. Baseline
emissions for the remaining pollutants
were established following review of
emission data from existing MWCs or,
where no data existed, on engineering
judgement. After assigning baseline
emissions, the design and operating
features of each model plant were
evaluated relative to the GCP
recommendations for each class of
combustors. Retrofit options were
recommended for the model plants that
lacked specific GCP design and
operating features, and emission
reductions and costs were estimated for
each retrofit application.
The variation in baseline CDD/CDF
emissions reflects the wide range of data
available from plants in the existing MWC
population. Several mass burn waterwall
and modular MWC model plants were
judged to satisfy the GCP criteria.
Baseline CDD/CDF emissions for these
model plants were 200-300 ng/dscm, and
retrofit recommendations were limited to
installation of CO emission monitors to
provide continuous verification of
performance levels. Several model plants
were assigned baseline CDD/CDF
emissions ranging from 2000 to 4000
ng/dscm, and fairly extensive design and
operating modifications were judged to
be necessary to achieve GCP. The
results of two combustion retrofit
programs at the Quebec City (Quebec)
and Hampton (Virginia) mass burn
waterwall MWCs are summarized in the
report. These retrofit programs provide
technical support for retrofit options that
were recommended for the model plants,
and for estimating emission reductions
that result from the combustor retrofits.
U.S. GOVERNMENT PRINTING OFFICE: 1990/748-012/20064
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P. J. Schindler is with Energy and Environmental ftesseareh Corp., Durham,
WC., 27707
James D. Kilgore is the EPA Project Officer (see below).
The complete report, entitled "Municipal Waste Combustion Assessment:
Combustion Control at Existing Facilities," (Order No. PB 90-154931/AS;
Cost: $23.00 subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Air and Energy Engineering 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
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Official Business
Penalty for Private Use $300
EPA/600/S8-89/058
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