EPA-450/3-79-009
A Review of Standards
of Performance for New
Stationary Sources -
Incinerators
by
Richard M. Helfand
Metrek Division of the MITRE Corporation
1820 Dolley Madison Boulevard
McLean, Virginia 22102
Contract No. 68-02-2526
EPA Project Officer: Thomas Bibb
Emission Standards and Engineering Division
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air, Noise, and Radiation
Office of AirQuality Planning and Standards _
Research Triangle Park, North Carolina 27711
March 1979
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This report has been reviewed by the Emission Standards and Engineering
Division, Office of Air Quality Planning and Standards, Office of Air, Noise
and Radiation, Environmental Protection Agency, and approved for publica-
tion. Mention of company or product names does not constitute endorsement
by EPA. Copies are available free of charge to Federal employees, current
contractors and grantees, and non-profit organizations - as supplies permit
from the Library Services Office, MD-35, Environmental Protection Agency,
Research Triangle Park, NC 27711; or may be obtained, for a fee, from the
National Technical Information Service, 5285 Port Royal Road, Springfield,
VA 22161.
Publication No. EPA-450/4-79-009
11
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ABSTRACT
This report reviews the current Standards of Performance for
New Stationary Sources: Subpart E - Incinerators. It includes a
summary of the current standards, the status of applicable control
technology, and the ability of incinerators to meet the current
standards. Compliance test results are analyzed and recommendations
are made for possible modifications to the standard. Information
used in this report is based upon data available as of November 1978,
iii
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ACKNOWLEDGMENT
The author wishes to thank Sally Price for her editorial
comments and assistance during the preparation of this document.
IV
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TABLE OF CONTENTS
LIST OF ILLUSTRATIONS
LIST. OF TABLES
1.0 EXECUTIVE SUMMARY •
1.1 Best Demonstrated Control Technology
1.2 Current Particulate Matter Levels Achievable
With Best Demonstrated Control Technology
1.3 Other Issues
1.3.1 Opacity Standard
1.3.2 Resource Recovery
1.3.3 Coincineration with Sewage Sludge
2.0 INTRODUCTION
3.0 CURRENT STANDARDS FOR INCINERATORS
3.1 Background Information
3.2 Facilities Affected
3.3 Controlled Pollutant and Emissions Level
3.4 Testing and Monitoring Requirements
3.4.1 Testing Requirements
3.4.2 Monitoring Requirements
3.5 Applicability of NSPS to Coincineration of Municipal
Solid Waste with Municipal Sewage Sludge
3.6 State Regulations
3.6.1 Particulate Standards
3.6.2 Opacity Standards
4.0 STATUS OF CONTROL TECHNOLOGY
.4.1 Status of Municipal Solid Waste Incinerators
Since the Promulgation of the Standard
4.1.1 Geographic Distribution
4.1.2. Municipal Incineration Trends
4.2 Municipal Incineration Processes
4.2.1 Charging of Solid Waste
4.2.2 Furnaces
4.2.3 Combustion Parameters
4.2.4 Residue Removal
Page
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vii
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TABLE OF CONTENTS (Concluded)
4.3 Emissions from Municipal Solid Waste Incinerators
4.3.1 Particulate Matter
4.3.2 Gaseous and Trace Metal Emissions
5.0 INDICATIONS FROM TEST RESULTS
5.1 Analysis of NSPS Test Results
5.1.1 Electrostatic Precipitator Control Results
5.1.2 Scrubber Control Results
5.1.3 Baghouse Results
5.2 Summary of Test Result Implications
6.0 FINDINGS AND RECOMMENDATIONS
6 . 1 Findings
6.1.1 Incinerator Developments
6.1.2 Process Emission Control Technology
6.1.3 Opacity Standard
6.1.4 Co incineration with. Sewage Sludge
6.2 Recommendations
6.2.1 Revision of the Standard
6.2.2 Def init ions
6.2.3 Research Needs
Page
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7.0 REFERENCES
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LIST OF ILLUSTRATIONS
Page
Figure Number
3-1
4-1
4-2
4-3
Interpretation of Coincineration
Standard When Total Waste is Greater
Than 50 Tons/Day
Location of Municipal Incinerators
in U.S.
Diagram of the In-Plant Systems with
Fly-Ash Collection and Conveying from
Cooling and Collection Operations
Rectangular Furnace
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4-8
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LIST OF TABLES
Table Number
3-1
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' 5-1
5-2
Applicability of 40 CFR 60 for
Coincineration with Sewage Sludge
Municipal Solid Waste Incinerators
Identified as New Sources
Incinerators Planned or Under Construction
Municipal Incinerator Test Results
Other Test Results (ESP)
Page
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vii
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1.0 EXECUTIVE SUMMARY
The objective of this report is to review the particulate matter
New Source Performance Standard (NSPS) of 0.18 grams/dscm (0.08
grains/dscf) at 12 percent C02 from the incineration of municipal
solid waste (Subpart E, 40 CFR 60). This review is given in terms of
developments in technology and new issues that have developed since
the original standard was promulgated in 1971. Possible revisions to
the standard are analyzed in the light of compliance test data avail-
able since promulgation of the standard. The following paragraphs
summarize the results and conclusions of the analysis, as well as re-
commendations for future action.
1«1 Best Demonstrated Control Technology
Particulate matter is present in the flue gas from incineration
of municipal refuse. In modern multichamber incinerators, uncontrol-
led particulate matter is generated at a rate of 5 to 35 kilograms/
metric ton (kg/Mg) or 10 to 70 Ib/ton of refuse. The electrostatic
precipitator (ESP) is the best demonstrated control technology for
particulate emissions from municipal solid waste incinerators. This
emission system has become the system of choice for the majority of
plants that have become subject to the NSPS or to local regulations
as stringent or more stringent than the NSPS.
The use of venturi scrubbers for particulate matter control, has
not been as successful in meeting the NSPS and, because of experience
with corrosion and increasing energy costs, its use will likely
1-1
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decrease. Only one incinerator operating with a venturi scrubber is
meeting the NSPS, and this unit has a new control device operating
with a relatively high pressure drop (35 to 40 inches water gauge).
Theoretically, baghouses have the highest removal efficiency
potential of any of the devices used to date. However, only one
incinerator in the U.S. has operated with a baghouse. The facility
met with mixed success due to corrosion problems associated with the
bags and baghouse as well as apparent periods of high emissions. An
experimental pilot unit was operated successfully. Further experi-
ence is required before baghouses can be considered the best ade-
quately demonstrated technology.
1.2 Current Particulate Matter Levels Achievable With Best
Demonstrated Control Technology
Test results since 1971 for nine facilities indicate that ESP
controlled incinerators have complied with the current standard. In
fact, two facilities in Massachusetts and Maryland successfully met
emissions standards of 0.11 grams/dscm (0.05 grains/dscf) at 12
percent C02 and 0.07 grams/dscm (0.03 grains/dscf) at 12 percent
C02, respectively. All of the ESP test results were below 0.11
grams/dscm (0.05 grains/dscf) at 12 percent C02. Given these
results, it is recommended that EPA consider revising the NSPS to a
more stringent level with consideration given to a standard of 0.11
grams/dscm (0.05 grains/dscf) at 12 percent C02. In developing a
revised standard, data should be obtained to assess the need for a
specific limitation on lead and cadmium emissions.
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1.3 Other Issues
1.3.1 Opacity Standard
Only three states do not have municipal solid waste incineration
opacity standards of 20 percent (Ringelmann No. 1). Illinois and
Indiana have opacity standards of 30 and 40 percent, respectively,
and Delaware has no standard. However, it is unknown how strictly
these standards are enforced or whether affected sources are con-
sistently able to comply. The rationale for not including an opacity
standard in the NSPS was the poor correlation found between opacity
and particulate concentrations from several tested facilities. Based
on the utility of opacity standards as an enforcement tool, it is ,
recommended that EPA consider revising the NSPS to include an opacity
standard set at a level consistent with the particulate standard.
1.3.2 Resource Recovery
A new development since 1971 is the increase in energy and re-
source recovery from municipal waste. As a result, solid waste is
now being processed to a fuel-like substance and burned either in
on-site boilers or as a substitute or addition to traditional fuels
in off-site boilers or other processing units. Clarification is
required as to whether preprocessed refuse is waste or fuel and what
standard, if any, applies. For instance, a facility designed to burn
processed refuse derived fuel for power generation would not be
subject to the current Subpart D for new sources, since that standard
only applies to facilities having the capability to burn greater than
250 x 106 Btu/hour of fossil fuel. A revised Subpart D standard
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has been proposed by EPA. It is unclear at this time how the final
revision will affect refuse firing.
1.3.3 Coincineration with Sewage Sludge
Various possibilities exist for incinerating municipal solid
waste and sewage sludge. There is currently no explicit statement in
either Subpart E or Subpart 0 (Standards of Performance for Sewage
Treatment Plants) that covers the appropriate standard to be used for
incinerators jointly burning both types of waste. It is suggested
that consideration be given to revising both Subparts E and 0 to
cover this situation.
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2.0 INTRODUCTION
In Section 111 of the Clean Air Act, "Standards of Performance
for New Stationary Sources," a provision is set forth which requires
that "The administrator shall, at least every four years, review and,
if appropriate, revise sugh standards following the procedure re-
quired by this subsection for promulgation of such standards...."
Pursuant to this requirement, the MITRE Corporation, under EPA
Contract No. 68-02-2526, is to review 10 of the promulgated NSPS
including the standards of emission control from incinerator furnaces
burning at least 50 percent municipal solid waste (refuse) with a
capacity of at least 45 Mg/day (50 tons/day).
This report reviews the current incinerator standard for parti-
culate matter and assesses the^need for revision on the basis of
developments that have occurred or are expected in the near future.
The following issues are addressed:
1. Definition of the present standard
2. Status of the incinerator industry and applicable control
technology
3. Particulate test results over the past several years
Based on the information contained in this report, conclusions
are presented and recommendations are made with respect to changes in
the NSPS and unresolved issues.
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3.0 CURRENT STANDARDS FOR INCINERATORS
3.1 Background Information
Prior to the promulgation of the NSPS in 1971, most municipal
solid waste incinerators utilized some form of mechanical settling
chamber (wet or dry) to prevent larger fly ash particles from enter-
ing the atmosphere. Uncontrolled emissions were on the order of 2.25
grams/dscm (1.0 grains/dscf) at 12 percent C02 and increasingly
stringent local and Federal regulations required more control. The
most comm.on controls included wet spray chambers or wetted baffle
walls that were capable of removing the larger particles in the fly
ash. This constituted about 20 to 30 percent of the total particu-
late matter by weight. The mechanical cyclone collector was used
extensively to increase collection efficiencies to values as high as
80 percent in order to meet regulations calling for 0.45 to 0.90
grams/dscm (0.2 to 0.4 grains/dscf) at 12 percent C02 (Hopper,
1977).
The estimated national particulate emissions from municipal
incineration in 1975 were between 60,000 and 100,000 tons or between
0.4 and 0.6 percent of all particulate emissions (EPA, 1978).
Between 1971 and 1976, the total national solid waste disposal
capacity of incinerators had decreased by 40 percent with a likely
proportional decrease in emissions (Hopper, 1977). The effect of the
NSPS standard on overall emissions has been minimal due to the
limited number of new installations since 1971.
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3.2 Facilities Affected
The NSPS regulates incinerators burning at least 50 percent
municipal type solid waste (refuse) that were under construction or
in the process of modification as of 17 August 1971. Each incinera-
tor furnace is the affected facility. The NSPS does not apply to
incinerator furnaces with a design capacity of less than 45 Mg/day
(50 tons/day) or to facilities designed to incinerate less than 50
percent municipal solid waste.
An existing incinerator is subject to the promulgated NSPS if:
(1) a physical or operational change in an existing facility causes
an increase in the emission rate to the atmosphere of any pollutant
to which the standard applies, or (2) if in the course of reconstruc-
tion of the facility, the fixed capital cost of the new components
exceeds 50 percent of the fixed capital cost that would be required
to construct a comparable new facility that meets the NSPS.
3.3 Controlled Pollutant and Emissions Level
The pollutant to be controlled at incinerator facilities by the
NSPS is defined by 40 CFR 60, Subpart E as follows:
On and after the date...no owner or operator subject
to the provisions of this part shall cause to be
discharged into the atmosphere from any affected
facility any gases which contain particulate matter
in excess of 0.18 grams/dscm (0.08 grains/dscf)
corrected to 12 percent C02«
The value for the standard was derived from tests at two domes-
tic incinerators where ESPs were in use. Particulate emissions
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ranged from 0.16 to 0.20 grams/dscm (0.07 to 0.09 grains/dscf)
corrected to 12 percent CC>2. In addition, two European incin-
erators with ESP controls were tested by EPA personnel. • Data from
these tests indicated emissions levels of 0.11 to 0.16 grams/dscm
(0.05 to 0.07 grains/dscf) at 12 percent C02. Limited data
available at the time indicated that both baghouses and high energy
(venturi) scrubbers could also meet a 0.18 grams/dscm (0.08 grains/
dscf) standard (EPA, 1971).
3.4 Testing and Monitoring Requirements
3.4.1 Testing Requirements
Performance tests to verify compliance with the particulate
standard for incinerators must be conducted within 60 days after
achieving full capacity operation, but not later than 180 days after
the initial startup of the facility (40 CFR 60.8). The EPA refer-
ence methods to be used in connection with incinerator testing
include:
1. Method 5 for concentration of particulate matter and
associated moisture content
2. Method 1 for sample and velocity traverses
3. Metho.d 2 for velocity and volumetric flow rate
4. Method 3 for gas analysis and calculation of excess air.
For Method 5, each performance test consists of three separate
runs each at least 60 minutes long with a minimum sample volume of
0.85 dscm (30.0 dscf). The arithmetic mean of the three separate
runs is the test result to which compliance with the standard applies
3-3
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(40 CFR 60.8). If one of the runs is invalidated due to weather or
equipment failure, the other two runs would be sufficient (upon
approval by EPA) for the determination of the arithmetic mean.
To establish a consistent reference point for comparing emis-
sion rates, concentrations are adjusted to 12 percent C02 by the
equation:
C12 -
12C
C02
where:
C12 is the concentration of particulate matter corrected to 12
percent C02
C is the Method 5 particulate concentration
% C02 is the percentage of C02 as measured by Method 3.
When a wet scrubber is used, the percent C02 is measured at the in-
let to the scrubber to avoid errors due to C02 absorption. Under
this condition it is also necessary to correct the C02 inlet meas-
urement for dilution air by adjusting the percent C02 by the ratio
of inlet to outlet volumetric flow rates or inlet to outlet excess
air.
Alternative testing equipment or procedures may be used (upon
approval by EPA) when the specified procedures cannot be applied
(e.g., stack geometry and limited work space require modification of
the location of the pollutant sampling trains).
3-4
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3.4.2 Monitoring Requirements
The only continuous monitoring required of incinerator operators
under the NSPS is the recording of daily charging rates and hours of
operation.
3.5 Applicability of NSPS to Coincineration of Municipal Solid
Waste with Municipal Sewage Sludge*
The coincineration of municipal solid waste and sewage sludge
has been practiced in Europe for several years and on a limited scale
in the U.S. Where energy resources are scarce and land disposal is
economically or technically unfeasible, the recovery of the heat
content of dewatered sludge as an energy source will become more
desirable. Due to the institutional commonality of these wastes and
advances in the preincineration processing of municipal refuse to a
waste fuel, many communities may find joint incineration in energy
recovery incinerators an economically attractive alternative to their
waste disposal problems (see Section 4.1.2).
Coincineration of municipal solid waste and sewage sludge as
described above is not currently explicitly covered in 40 CFR 60.
The particulate standard for municipal solid waste described in
Subpart E (0.18 grams/dscm or 0.08 grains/dscf at 12 percent C02)
applies to the incineration of municipal solid waste in furnaces with
*This topic is being studied by The MITRE Corporation in its review
of NSPS for sewage sludge incinerators.
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a capacity of at least 45 Mg/day (50 tons/day). Subpart 0, the par-
ticulate standard for sewage sludge incineration (0.65 grams/kg dry
sludge input or 1.3 lb/ton dry sludge), applies~to any incinera-
tor that burns sewage sludge with the exception of .small communities
practicing coincineration.*
To clarify the situation when coincineration is involved, the
EPA Division of Stationary Source Enforcement determined that when an
incinerator with a capacity of at least 45 Mg/day (50 tons/day) burns
at least 50 percent municipal solid waste, then the Subpart E applies
regardless of the amount of sewage sludge burned. When more than 50
percent sewage sludge and more than 45 Mg/day (50 tons) is inciner-
ated, the standard is based upon Subpart 0, or alternatively, a pro-
ration between Subparts 0 and E. Table 3-1 summarizes the current
rules that apply to solid waste and sewage sludge incineration
(Farmer, 1978).
The alternative of prorating the Subparts E and 0 is not
straightforward, since the two standards are stated in different
units. The proration scheme requires a transformation of the munici-
pal incineration standard (Subpart E) from grams per dry standard
cubic meters (grains per dry standard cubic feet) at 12 percent C02
to grams per kilograms (pounds per dry ton) refuse input, or a trans-
formation of the sewage sludge standard (Subpart 0) from grams per
*Special rules apply to communities of less than approximately 9000
persons. See the Federal Register (1977).
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TABLE 3-1
APPLICABILITY OF 40 CFR 60 FOR
GOINGINERATION WITH SEWAGE.-SLUDGE
Sewage Sludge
(percent)
51-100
0-50
0
100
1-99
Municipal
Refuse
(percent)
0-49
50-100
100
0
1-99
Incinerator
Charging Rate
>50 Tons/Day Total Waste
>50 Tons /Day Total Waste
250 Tons/Day Municipal Refuse
Any Rate
250 Tons/Day Total Wastes,
Applicable
Subpart
(40 CFR 60)
Subpart 0 or
ration of 0
Subpart E
None
Subpart 0
Pro-
and E
11-99
0-10
>1.1 Dry Tons/Day Sewage Sludge Subpart 0
1-89 <50 Tons/Day Total Wastes,
fl.l Dry Tons/Day Sewage Sludge Subpart 0
90-100 250 Tons/Day Total Wastes
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dry kilograms (pounds per dry ton) input to grams per dry standard
cubic meters at 12 percent C02. Such transformations are dependent
on the percent C02 in the flue gas stream', the stochiometric air
requirements, excess air, the volume of combustion products to
required air, the percent moisture in refuse or sludge, and the heat
content of the sludge and solid waste.
As shown in Figure 3-1, the proration scheme, as currently
determined, has a discontinuity when a municipal incinerator burns 50
percent solid waste. Nominal equivalent values for sludge and refuse
emissions appear on the vertical axis for each standard.
3.6 State Regulations
3.6.1 Particulate Standards
Every state has an explicit standard for particulate emissions
resulting from incineration of municipal solid waste (Environmental
Reporter, 1978). In addition, most states have explicit standards
for new incinerators which tend to be more stringent than those for
existing incinerators. A survey of state regulations indicates that
23 states have standards that either reference the Subpart E NSPS or
have exact copies of Subpart E written into their regulations. Nine
states have standards less stringent than the NSPS and do not refer-
ence Subpart E. Three states have more stringent regulations
Massachusetts and Illinois, 0.11 grams/dscm (0.05 grains/dscf) and
Maryland, 0.07 grams/dscm (0.03 grains/dscf) at 12 percent C02.
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New Mexico is the only state to explicitly prohibit incineration.
The remaining states have emission standards that are a function of
the amount of waste being incinerated. If one assumes a 272-Mg/day
(300-ton/day) furnace and 10,350 Joule/Mg (4450 Btu/lb) refuse higher
heat value, of the remaining states, 11 would have less stringent
standards and Delaware, Nevada and North Carolina would have more
stringent standards (Hopper, 1977).
In summary, it appears that the current NSPS is identified by
most states as reflecting their most stringent incinerator emission
standards. However, the fact that at least six states have more
stringent regulations than the NSPS may indicate the possibility of a
need for tightening the standard.
3.6.2 Opacity Standards
The current NSPS does not contain a standard for opacity. Test-
ing of incinerators prior to promulgation of the standard in 1971 did
not indicate a consistent relationship between emission opacity and
concentrations (Trenholm, 1978). Nevertheless, a survey of current
state regulations shows that every state has an opacity standard for
new incinerators of 20 percent (Ringelmann No. 1) or stricter except
Illinois (30 percent), Indiana (40 percent), and Delaware, which has
no opacity standard. In fact, Maryland and the District of Columbia
have "no visible emissions" standards. (The"District of Columbia,
• however, also has a new source ban on the incineration of municipal
waste.) -It is unknown how strictly these standards are enforced or
whether sources are consistently in compliance.
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While data are still limited about the relationship between
opacity and particulate emissions from incinerators, it appears that
most states find an opacity standard a convenient gross measure of
emissions. Based upon the fact that existing opacity standards of 20
percent are currently in force in almost every state, EPA may wish to
consider further study of the relationship between opacity and mass
emissions, and development of an opacity limit as a possible addition
to the current NSPS. An opacity limit would be useful to EPA
enforcement personnel in assessing proper operation and maintenance
of incinerators and control systems without performing extensive
stack testing.
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4.0 STATUS OF CONTROL TECHNOLOGY
4-1 Status of Municipal Solid Waste Incinerators Since the
Promulgation of the Standard
4.1.1 Geographic Distribution
In 1972 there were 193 incinerator plants* operating in the U.S.
(Hopper, 1977). By 1977 the number of plants had been reduced to 103
with 252 furnaces and a total solid waste disposal capacity of about
36,000 Mg/day (40,000 tons/day). Since the standard was originally
promulgated, five incinerator units have become operational. Table
4-1 lists the units subject to the NSPS and their design capacity.
Table 4-2 presents the new units that are planned or under
construction at the current time. Figure 4-1 shows the distribution
of incinerators in the U.S. (Hall and Capone, 1978). For the most
part, existing units are concentrated in the Northeast and Midwest.
4.1.2 Municipal Incineration Trends
As previously indicated, the number of municipal waste incinera-
tors has been reduced during the past 6 years. Among the possible
reasons for this decline are the stricter emission limits that have
been placed on emissions from incinerators by Federal, state, and
local agencies and the opting by communities for alternative methods
of disposal such as sanitary landfills that may be more economical
than upgrading incinerator facilities. A second factor that may be
affecting use of incineration as a waste disposal
*An incinerator plant may contain more than one NSPS facility, or
furnace.
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TABLE 4-1
MUNICIPAL SOLID WASTE INCINERATORS "
IDENTIFIED AS NEW SOURCES
State
Massachusetts
Massachusetts
Tennessee
Utah
Maryland
^Subject to 0
^Subject to 0
FF: Fabric
City /Name
East Bridgewater
Saugus
Nashville Thermal
Ogden No. 3
2
Pulaski No. 4
.11 grams/dscm (0.05
.07 grams/dscm (0.03
Filter Baghouse
No. of
Furnaces
1
2
2
1
2
grains /dscf)
grains/dscf)
Capacity
(tons /day)
300
1200
720
150
600
Particulate
Control Method
FF3
ESP' :
ESP
ESP
ESP
Massachusetts Standard
Maryland Standard
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TABLE 4-2
INCINERATORS PLANNED OR UNDER CONSTRUCTION
Region
I
II
III
IV
V
X
City
West Warwick, R.I.
Albany, N.Y.
Glen Cove, N.Y.
Hempstead, N.Y.
Niagara Falls, N.Y.
Wilmington, Del.
Hampton Roads, Va.
Huntington, W. Va.
Dade County, Fla.
Pinellas County, Fla.
Kenton County, Ky.
Detroit, Mich.
Niles, Mich.
Owosso, Mich.
Duluth, Minn.
Akron, Ohio
Tacoma, Wash.
Source: EPA Regional Compliance Data Systems and St. Clair, 1978.
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(O
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o
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process is the relatively new concept of resource recovery including
the recycling of material and the use of the energy content -of solid
waste as a processed fuel source. A recent survey indicates that"
there are at least 28 resource recovery systems in operatiTorf, under
construction, or in the final contract stage (St. Clair, 1978).
Total capacity of these operations will be about 27,000 Mg/day
(30,000 tons/day), or about three-fourths of the current installed
incinerator capacity.
For the most part, these systems are characterized by substan-
tial processing of solid waste into usable recycled material and a
homogenous fuel. The homogenous fuel may be in the form of a slurry
or a type of "fluff" material that can be transported to other sites
for eventual combustion. It is important to note that the phenomena
of processing solid waste prior to combustion is a growing trend that
has implications in the definition of incineration. For example,
when processed refuse derived fuel (RDF) is used in an industrial or
utility boiler, are the emission standards for Subpart E in effect or
are other standards to be used? If the boiler is located at the new
solid waste processing center, is it a boiler or an incinerator? In
Duluth there are plans to use RDF to provide fuel for incinerating
sewage sludge in a fluidized bed reactor. The solid waste input
before processing will be 360 Mg/day (400 tons/day), while the sludge
to be incinerated will total about 90 Mg/day (100 tons/day) of dry
solids. If the entire facility were considered, Subpart. E would
4-5
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apply since more than 50 percent of the waste processed is municipal
waste. If only the fluidized bed incinerator is considered, then a
proration scheme between Subparts E and 0 might be necessary (see
Section 3.5), since the RDF is solid waste derived and more than 45
Mg/day (50 tons/day) is being incinerated. If the RDF is considered
a fuel, then Subpart 0 alone would apply.
The above areas of ambiguity in definition require clarifica-
tion. If RDF is considered to be a.fuel, then installations burning
RDF will not likely be considered incinerators. I£ is suggested that
the incinerator definition be examined in new facilities where elec-
trical or steam generation for commercial use is an integral part of
the resource recovery system. To date these locations have been
considered incinerators (e.g., Saugas, Massachusetts and Hempstead,
New York). Due to improved design and the homogeneity of the fuel
and removal of recoverable material, the emission characteristics of
these new facilities may be'considerably different than those from
the traditional refractory wall incinerator with no preprocessing of
the solid waste.
4.2 Municipal Incineration Processes*
Solid waste incineration, when carried out under the•proper com-
bination of turbulence, time and temperature, can reduce the charge
*Much of the information in this section was extracted from Hopper,
1977.
4-6
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to a noncombustible residue consisting only of the glass, metal and
masonry materials present in the original charge. Figure'4-2
presents a generic view of an incinerator processing system.
4.2.1 Charging of Solid Waste
Solid waste is charged either continuously or in batches. In
the continuous process, solid waste is fed to the furnace directly
through a rectangular chute that is kept filled at all times to main-
tain an air seal. In the batch process, solid waste is fed to the
furnace intermittently through a chute, or the furnace may be fed
directly by opening the charging gate and dropping the waste directly
from a crane bucket, front-end-loader, .or bulldozer. A ram can also
be used to feed a batch of material directly onto the grate through
an opening in the furnace wall. Continuous feed minimizes irregu-
larities in the combustion system. Batch feeding causes fluctuations
in the thermal process because of the nonuniform rate of feeding and
the intermittent introduction of large quantities of cool air.
!
4.2.2 Furnaces
The combustion process takes place in the furnace of the
incinerator, which includes the grates and combustion chambers.
There are numerous designs or configurations of furnaces and grates
to accomplish combustion, and presently no one design can be consi-
dered the best.
Four types of furnaces are commonly used for the incineration
of municipal solid waste: vertical circular, multicell rectangular,
4-7
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4-8
-------
rectangular, and rotary kiln. Although these furnaces vary in
configuration, total space required for each is based on a heat
release rate of about 672 MJ/m3* (18,000 Btu/ft3) of furnace
volume/hour. However, heat release rates can vary from 467 to 934
MJ/m3 (12,500 to 25,000 Btu/ft3).
The rectangular furnace is the most common type of recently
constructed municipal incinerator (Figure 4-3). Several grate
systems are adaptable to this form. Commonly two or more grates are
arranged in J:iers so that the moving solid waste is agitated as it
drops from one level to the next. Each furnace has only one charging
chute. Secondary combustion is frequently accomplished in the back
end of the furnace which is separated from the front half by a
curtain wall. This wall serves to radiate heat energy back towards
the charging grate to promote drying and ignition as well as to
increase combustion gas velocity and the level of turbulence.
A grate system must transport the solid waste and residue
through the furnace and, at the same time, promote combustion by
adequate agitation and passage of underfire air. The degree and
methods of agitation on the grates are important. The abrupt
tumbling encountered when burning solid waste drops from one tier to
another promotes combustion. Abrupt tumbling, however, may contri-
bute to entrainment of excessive amounts of particulafe matter in the
*MJ/mJ =10° Joules/cubic meter.
4-9
-------
LLJ
O
CO =>
UJ CC
ga
Ill
4-10
-------
gas stream. Continuous gentle .agitation promotes combustion and
limits particulate entrainment. Combustion is largely achieved by
air passing through the waste bed from under'the grate, but excessive
amounts of underfire air contribute to particulate entrainment. Some
inert materials such as glass bottles and metal cans aid combustion
by increasing the porosity of the fuel bed. Conversely, inert
materials inhibit combustion if .the materials clog .the grate opening.
Mechanical grate systems must withstand high temperatures, ther-
mal shock, abrasion, wedging, clogging and heavy loads. Such severe
operating conditions can result in misalignment of moving parts,
bearing wear, and warping or cracking of castings.
Grate systems may be classified by function, such as drying,
ignition and combustion. Grates for solid waste incineration may
also be classified by mechanical type and include traveling,
reciprocating, oscillating, and reverse reciprocating grates;
multiple rotating drums; rotating cones with arms; and variations or
combinations of these types. In the U.S., traveling, reciprocating,
rocking, rotary kiln and circular grates are most widely used.
4.2.3 Combustion Parameters
4.2.3.1 Drying and Ignition. Since most municipal solid waste
contains substantial quantities of both surface and internal mois-
ture, a drying process is necessary before ignition can occur and the
combustion process can proceed. This drying process continues
throughout the entire length of the furnace, but proceeds at the
4-11
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greatest rate immediately following charging of the solid waste.
Once moisture is removed, the temperature of the substance can be
raised to the ignition point.
4.2.3.2 -Primary arid Secondary Combustion. The incineration
combustion process occurs in two overlapping stages, primary
combustion and secondary combustion. Primary combustion generally
refers to the physicochemical changes occurring in proximity to the
fuel bed and consists of drying, volatilization and ignition of the
solid waste. Secondary combustion refers to the oxidation of gases
and particulate matter released by primary combustion. To promote
secondary combustion, a sufficiently high temperature must be
maintained, sufficient air must be supplied, and turbulence or mixing
should be imparted to the gas stream. This turbulence must be
intense and must persist long enough to ensure thorough mixing at the
temperatures required for complete combustion.
4.2.3.3 Combustion Air. In the combustion process oxygen is
needed to complete the chemical reaction involved in burning. The
air necessary to supply the exact quantity of oxygen required for the
chemical reactions is termed stoichiometric or theoretical air. Any
additional air supplied to the furnace is termed excess air and is
expressed as a percentage of the theoretical air.
Air that is purposely supplied to the furnace from beneath the
grates is termed underfire air. Overfire air is that air introduced
above the fuel bed. Its primary purpose, in addition to supplying
4-12
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oxygen, is to provide turbulence. Infiltration air is the air that
enters the gas passages through cracks and openings and is frequently
included in the figure for overfire air.
The., proportioning of underfire and overfire air depends on
incinerator design. Very often the best proportions are determined
by trial and error. In general, as the underfire air is decreased,
the burning rate is inhibited; but with increasing underfire air,
particulate emissions are likely to increase.
To supply adequate air for complete combustion and to promote
turbulence, a minimum of 50 percent excess air should be provided.
Too much excess air, however, can be detrimental because it lowers
furnace temperatures. In general, refractory furnaces require 150 to
200 percent excess air; whereas water wall furnaces require only 50
to 100 percent excess air.
4.2.3.4 Furnace Temperatures. At the air intake, combustion
air may be either at ambient temperature or preheated, depending on
furnace design. Immediately above the burning waste, the temperature
of the gases generally ranges from 1150° to 1370°C (2100° to 2500°F);
and for short periods of time, it may reach 1540°C (2800°F) in
localized areas. When the gases leave the combustion chamber, the
temperature should be between 760° to 980°C (1400° to 1800°F), and
the gas temperature entering the stack should be less than 540°C
(1000°F). Where induced draft fans, ESPs and other devices requiring
lower gas temperatures are used, the gases have to be cooled further
to about 260° to 370°C (500° to 700°F).
4-13
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Regulation of the combustion process through control of furnace
and flue gas temperatures is achieved principally through the use of ;
excess air, water evaporation, and heat exchange. Of these, the use
of excess air is the most common and, in refractory furnaces, is
often the only method of control. Even when another cooling method
is available, some excess air is still used but primarily for ensur-
ing turbulence and complete combustion. .;
Heat exchange through the use of water tube walls and boilers, a
well-established European practice, is attracting greater attention
in the U.S. A distinct advantage of heat exchangers in cooling gases
is that additional gases or vapors are not added to the gas flow to
reduce temperature, and a smaller gas volume results.- Because gas
volume is greatly reduced, the size of collection devices, fans and
gas passages can be reduced. Heat recovery and utilization can bring
further economies through the sale of steam or the generation of
electricity.
4.2.4 Residue Removal
Residue, or all of the solid material remaining after burning, j
includes ash, clinkers, tin cans, glass, rock, and unburned organic
substances. Residue removal can be either a continuous operation or !
an intermittent batch process. In a continuous feed furnace, the !
greatest volume of residue comes off the end of the burning grate;
and the remainder comes from sittings and fly ash. The residue from
the grate must be quenched and removed from the plant.
4-14
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4.3 Emissions from Municipal Solid Waste Incinerators
4.3.1 Particulate Matter
The uncontrolled particulate emissions from an incinerator plant
vary widely and are dependent on the composition of the refuse being
incinerated, the design of the preprocessing and charging system, the
combustion chamber design, and the operating procedures with respect
to air control and burning rates on the grate. Uncontrolled emis-
sions rates cited in the literature range from as low as 5 kg/Mg (10
Ib/ton) of refuse to as high as 35 kg/Mg (70 Ib/ton) of refuse
(Smith, 1974). The EPA handbook of emission factors suggests an
uncontrolled emission value of 15 kg/Mg (30 Ib/ton) of refuse
(EPA, 1977).
Studies indicate that the proper use of overfire and tinderfire
air can have a significant effect in reducing the amount of parti-
culate matter emitted (Hopper, 1977). Too much excess air results in
higher velocites that increase carryover of pairticulates to the stack
and lower furnace temperature conditions to below that required for
complete combustion. Overfire air, when properly applied, can reduce
the carryover of unburned combustible particulate by ensuring com-
plete burnout. Since entrained flyash from the grate increases
roughly with the square of the air velocity through the grate,
limiting underfire air and, thus, the combustion rate on the grate,
can reduce the amount of particulate reaching the stack (and increase
the amount leaving as residue from the grate). Thus, the proper
4-15
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control of the underfire and overfire air, as well as grate speed and
charging rate, can minimize emissions.
4.3.1.1 Particle Size Distribution. Of critical importance
for air pollution control purposes is the particle size distribution
entering the stack air pollution control device. Data from three re-
fractory lined incinerators indicated a weight distribution of 23 to
38 percent below 10 microns, and 13 to 23 percent below 2 microns
(Smith, 1974). Inlet particulate size data from a waterwall
incinerator indicated that 26 to 56 percent were below 10 microns and
14 to 32 percent were below 1 micron (Bozeka, 1976). The fineness of
the particle size was further indicated by the fact that 10 to 22
percent of the particulate matter was found to be below 0.3. Data
from another continuous feed refractory furnace showed 40 percent of
the particulate matter below 2.0 microns (Jacko and Neuendorf, 1977).
The differences among the various data may reflect design differences
but, it should be pointed out, may also reflect differences in refuse
composition and the fact that the waterwall data were taken when the
facility was new.
The limited data discussed above indicate that there are sub-
stantial quantities of small particles exiting municipal incinera-
tors. This result has led to the general recognition that high
efficiency collector systems are necessary to catch the smaller
particles so as to minimize overall emissions and, importantly, the
respirable particulate emissions.
4-16
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4.3.1.2 Pre-NSPS Control Techniques. In general, the use of
control systems on municipal incinerators has evolved from simply re-
ducing gas velocity in settling chambers to allowing large particles
to settle out to the use of sophisticated ESPs that remove up to 99
percent of all particulate matter. Early systems for partieulate
removal involved the use of wetted baffle walls that provided wetted
impingement surfaces and offered low pressure drops to minimize
energy losses. Collection efficiencies for the most part were below
50 percent (Hopper, 1977). .
Many of the incinerators constructed in the 1955-1965 period
utilized mechanical cyclone collectors. Removal efficiencies of
these devices ranged from 60 to 80 percent and operated at pressure
drops of 2 to 4 inches water guage. Another approach was the use of
various scrubber techniques including the submerged entry of gases,
the spray wetted-wall cyclone, and the venturi scrubber. For the
most part, the cyclone and scrubber techniques, excluding venturi
scrubbers, do not have the collection efficiencies required for the
current standards, given the nominal particle size distribution
described in Section 4.3.1.1.
4.3.1.3 Control Devices for Satisfying the NSPS. Given the
suggested EPA uncontrolled emission factor of 15 kg/Mg (30 Ib/ton) of
refuse and that the NSPS standard of 0.18 grams/dscm (0.08 grains/
dscf) at 12 percent C02 is roughly equivalent to 0.75 kg/Mg
4-17
-------
(1.5 Ib/ton) of refuse, the removal efficiency is about 95 percent
with a potential range of between 85 and 98 percent. In 1971, when
the emission standard was promulgated, the ESP was the only proven
technology for this type of efficiency, and that was based primarily
on experience on two incinerators in the U.S. and experience with
ESPs in Europe. Based mostly on experience with controlling parti-
culate matter in other industries and the expected particle size
distribution, venturi scrubbers operating in the range of 15 to 20
inches water guage pressure drop and fabric filter baghouses could
also be used to control emissions to the 0.18 grams/dscm (0.08
grains/dscf) at 12 percent C02 level (EPA, 1971). The experience
with these various devices over the past 7 years is described in
Section 5.
4.3.1.4 Incinerator/Device Characteristics. The proper oper-
ation of an ESP is dependent on the moisture content, temperature
velocity, constituency of the gas stream, and the electrical resis-
tivity properties of the particles. Resistivity is a function of the
particle characteristics and the gas stream, parameters discussed
previously, especially temperature and humidity. Too high a resisti-
vity can cause accumulation on the collector plates and arcing within
the collected particle layer, which can reentrain captured particles.
Too low a resistivity can cause reentrainment due to loss of charge.
It has also been observed that poor combustion in the incinerator
4-18
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will generate large proportions of carbonaceous material in the
particulate matter, which causes the particles to rapidly lose charge
and be reentrained.
The above characteristics have led to design parameters that
call for input exhaust temperatures between 205° to 315°C (400° to
600°F) and, when exhaust is cooled by air dilution or heat exchanger
boilers, the addition of proper amounts of moisture. The variability
in feed moisture and waste content can affect the overall effective-
ness and must be adjusted during operations. The ESPs generally
operate with very low pressure drops of 1 to 2 inches water guage.
Venturi scrubbers have met with only limited success with re-
,'
spect to controlling particulate matter at the NSPS level (see Sec-
tion 5). The removal efficiency of venturi scrubbers is theoreti-
cally proportional to the energy input and particle size distribu-
tion. The accelerated mixing of gases and scrubbing liquid produce
enlarged "wet" particles which are then removed by a cyclonic mist
eliminating section. Venturi scrubbers are generally capable of
throat variation controls to maintain constant pressure drop over
varying air flows or varying pressure drops with constant air flow.
Large high pressure induced draft fans are required to maintain
exhaust gas flows.
Historically, the principal advantage of the venturi scrubber
has been its lower capital investment cost as compared with the ESP,
its relative simplicity and its capability to absorb some gaseous
4-19
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emissions. However, with rising energy costs and the need to treat
scrubber effluents, the operational disadvantages have caused ESP
controls to be used for most incinerator installations (see Section
5).
Baghouse applications for municipal incinerators were considered
a feasible control device for meeting the NSPS in 1971, although not
demonstrated at the time. Since then, an experimental unit was
tested and one incinerator has employed a baghouse with mixed suc-
cess. The basic premise of baghouse operation is the filtration of
particulate matter through impingement, sieving, diffusion, and
electrostatic attraction. Draft fans are used to propel the gas ;
through the baghouse to account for a 6 to 10 inch water guage pres-
sure drop. Collected particles are periodically removed from the
bags by shaking or other methods and collected in a hopper for
disposal.
As with the ESP, baghouse operation is sensitive to temperature
and humidity. Too high a gas temperature will burn the bags (e.g., ;
greater than 305°C (550°F) and too low a gas temperature with high
moisture content will cause the bags to "blind" or become encrusted
with a deposit that cannot easily be removed. Therefore, municipal
incinerators with highly variable input refuse heat and moisture
content must have a very tight control system to guarantee proper
baghouse operation. The additional problem of chemical corrosion and
bag disintegration is controllable by special bag coatings or
pretreating of the input gas stream with neutralizing chemicals.
4-20
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4.3.2 Gaseous and Trace Metal Emissions
Gaseous and trace metal emissions are not controlled under the
present NSPS. A limited amount of work has'been performed in the
area of ..evaluating the magnitude of these emissions from municipal
solid waste incinerators. In particular, the emission of hydrochloric
acid (HCL) from the increased incineration of polyvinyl chlorides has
been studied with mixed results. One recent study at a solid waste
incinerator indicated a lower emission level than that generally
found in the literature (Jahnke et al., 1977). This study noted
that HCL in the gaseous phase is difficult to measure and that higher
HCL measurements previously reported may have been due to the in-
clusion of HCL entrained in moisture droplets as opposed to gaseous
HCL.
One study of trace metals was performed at a municipal incinera-
tor downstream of a plate scrubber control device (Jacko and
Neuendorf, 1977). This study indicated that respirable particulates
accounted for 40 percent of total particulate emissions. Cadmium
emissions were on the order of 0.2 percent of all particulate emis-
sions and about 0.4 percent of emissions less than 2 microns. Lead
concentrations were about 4 percent of all particulate matter and 11
percent of respirable particulates emitted from the scrubber.
Emission factors were 9xlO~3 kg/Mg (18xlO~^ib/ton) refuse for
cadmium and 1.9x10"1 kg/Mg (3.8xl010~llb/ton) refuse for lead.
4-21
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There is currently an effort underway within EPA to indepen- ,
dently look at the need to regulate cadmium. Separate documents :
have been prepared which examine emissions, resulting atmospheric
concentrations, and population exposure. These documents are part of
an overall EPA program to satisfy requirements of the 1977 Clean Air
Act to evaluate the need to regulate emissions of cadmium to the air
(EPA, 1978a; 1978b; 1978c; 1978d).
4-22
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5.0 INDICATIONS FROM TEST RESULTS
A survey of the literature and polling of various EPA regional
offfces was performed to obtain NSPS incinerator compliance t'e'st data
or data to satisfy local regulations. The number of new incinerators
was difficult to determine, since the exact date when construction
had begun for new or rebuilt facilities had not been well documented.
Since the important factor with respect to the NSPS is technology
capability for pollutant removal, data were collected for all
sources that have been required to meet standards similar to the
NSPS. Of particular value was a study performed by GCA, Inc. for
the Division of Stationary Source Enforcement, EPA, which summarized
compliance test results as of mid-1978 (Hall and Capone, 1978).
5.1 Analysis of NSPS Test Results
The results of 22 tests of various incinerator facilities are
summarized in Tables 5-1 and 5-2. Table 5-1 presents test results
reportedly performed according to EPA Reference Method 5 for
facilities subject to various regulations as stringent or more
stringent than the NSPS. Table 5-2 summarizes 1970 to 1973 ESP test
results from facilities for which the test method was not cited and
the data not necessarily corrected to 1-2 percent C02 (Bump, 1976).
5.1.1 Electrostatic Precipitator Control Results
Tables 5-1 and 5-2 indicate that ESP control technology is
capable of limiting emissions to values below the 0.18 grams/dscm
5-1
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TABLE 5-2
OTHER TEST. RESULTS (ESP)
State
Montreal
New York
New York
Florida
Massachusetts
Pennsylvania
New York
New York
City /Name
Des Carriers
So Shore #4.
SW Brooklyn
Bade County
Braintree
Harrisburg
Hunt in gt on
Hamilton Ave
Size
(tons /day)
300
250
250
300
120
360
200
250
Test Results
0.0133 grains/dscf
0.0799 grains/dscf
0,129 grams /dscm
0.03 grains/dscf @
12% C02
0.027 grains/dscf
0.108 grains/dscf
0 .09-0 . 10 grams /dscm
0.146 grains/acfm
0.0346 grains/acfm
Date
1970
1971
1971
1974
1971
1971
1973
1972
1971
Source: Bump, 1976.
5-3
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(0.08 grains/dscf) at the 12 percent CC>2 level. This technology is
capable of very high removal efficiencies above those required for
the current NSPS. The Baltimore Pulaski Number 4 incinerator .
emission control system, for instance, meets the strict Maryland
standard for incinerators of 0.07 grams/dscm (0.03 grains/dscf) at 12
percent CC^. Similarly, the Saugas, Massachusetts facility was
designed for the state standard of 0.11 grams/dscm (0.05 grains/dscf)
at 12 percent C02 and was successfully tested at this level of
compliance.
The results of tests to date at facilities with ESPs indicate
f * i
that the NSPS particulate emission standard could be made more strin-:-
gent. Based on enforcement experience, several EPA regions made
recommendations that a more stringent standard should be considered
(Watson et al., 1978). However, limited test data indicate that
performance may deteriorate with time due to aging of the combustion
facility, aging of the electrostatic precipitator, changes in the
refuse mix, or all of these factors (Bump, 1976). For this reason,
the newer facilities listed in Table 5-1 should be retested to
determine their emission characteristics after several years of ;
operation.
5.1.2 Scrubber Control Results
The use of scrubbers on municipal incinerators has met with
mixed results and an overall difficulty in satisfying the 0.18
grams/dscm (0.08 grains/dscf) at the 12 percent CC>2 particulate i
5-4 '.
-------
emission standard. A study to specifically evaluate scrubber per-
formance was completed by GCA, Inc. in mid-1978, and their observa-
tions for each scrubber-controlled incinerator listed in Table 5-1
are quoted here (Hall and Capone, 1978).
• Calumet, Illinois
The Calumet incinerator in Chicago, Illinois
is an older system that began operation in
1959. Particulate control equipment orig-
inally consisted of settling chambers fol-
lowed by sprays and impingement baffles.
When standards became more strict, a flooded
baffle system was installed on furnace No. 1
in 1969. The flooded baffle system, how-
ever, failed to meet the standard. In 1971
an Ovitron wet gas scrubber was installed on
furnace No. 5. In the period of February
1972 to September 1973 venturi scrubbers
manufactured by Combustion Equipment As-
sociates were installed on furnaces Nos. 2,
3, 4 and 6.
Initial investigations indicated that the
Calumet incinerator was in compliance but
additional evaluations indicate that com-
pliance is doubtful. EPA Region V clas-
sifies the test results as inconclusive
because of variable results and the test
locations. Stack tests were conducted in
breachings under very turbulent con-
ditions. New ports are being installed
in more suitable locations and additional
tests are scheduled for May 1978. The
only test results available to GCA are
from furnace No. 5. These 1975 test re-
sults show an emission rate of 0.2385'
gr/dscf or almost five times the standard
of 0.05 gr/dscf....
Follow-up conversations with state personnel indicate that the
Calumet facility has had opacity problems, and modification to the
facility is underway. The 0.046 to 0.049 grains/dscf test result
5-5
-------
given in Table 5-1 represents initial compliance data tests for the
State of Illinois.
• Louisville, Kentucky
The Louisville, Kentucky incinerators are controlled
by venturi scrubbers with 20 to 22 in. W.C. pressure
drops. These units also appeared to be in compliance
during initial investigations. However, at this time
the compliance status is unknown. Tests are con-
ducted by the local agency and formal test reports
are not prepared. At GCA's request, a summary of the •
most recent tests was prepared. During the October
1976 tests on unit No. 2, problems were encountered
with the CC>2 measurements (CC>2 results before the
scrubber were 2.0, 5.2 and 1.9 percent) contributing
to an average particulate emission rate of 0.443
gr/dscf corrected to 12 percent CC^. If the real
CC>2 concentrations were 6 percent, then the average
emission rate is 0.22 gr/dscf corrected to 12 percent
CC>2. This unit apparently does not comply with
0.08 gr/dscf. New prescrubber(s) are being installed '.
on at least one unit and tests will be conducted in
April or May 1978. Earlier test results have been
summarized by Environmental Laboratories Inc.
September 1975 tests on Louisville No. 2 show an
average emission rate of 0.056 gr/dscf. November
1975 tests on unit No. 3 show 0.072 gr/dscf and
November 1976 tests on unit No. 4 show 0.066 gr/dscf.
These earlier tests indicate compliance....
Discussions with county personnel indicated that a prescrubber
located upstream of the venturi scrubber deteriorated quickly after
initial startup and is being redesigned. The actual pressure drop in
the venturi scrubber has been in the 15- to 18-inch water guage range
rather than the 20- to 22-inch design range. Another factor that
county personnel noted was a suspected feedback linkage between the
gas pressure drop in the scrubber and combustion changes in the
furnace.
5-6
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• Sheboygan Falls, Wisconsin
The Sheboygan, Wisconsin incinerator is a rela-
tively new facility. It is required to meet a 0.08
gr/dscf state standard. Whether or not it is an
NSPS facility depends on its operating schedule.
It has been operating only 8 hours per day and
incinerating only 30 ton/day of refuse. This unit
was designed and built to meet 0.08 gr/dscf. De-
cember 1977 test results show an emission rate of
0.15 gr/dscf. The use of a spray chamber with baf-
fles to meet a 0.08 gr/dscf standard seems to be a
poor choice of control equipment. The facility has
been ordered to close.
This incinerator is presently closed while alternative control
techniques are examined. While peripheral to the current discussion,
it should be pointed out that the municipality has claimed that this
facility was designed with excess capacity and really was only meant
to process 27 Mg/day (30 tons/day). Since the NSPS only applies to
facilities incinerating at least 47 Mg/day (50 tons/day) the munici-
pality felt that the 0.18 grams/dscm (0.08 grains/dscf) standard
should not apply to this facility.
• Pawtucket, Rhode Island
The Pawtucket incinerator appears to comply with
the state particulate emission standard of 0.08
gr/dscf. A venturi scrubber operating at 35 to
40 in W.C. pressure drop is used to achieve com-
pliance. The incinerator consists of two
furnaces (one is described below) built in
1965....Environmental Laboratories, Inc. con-
ducted stack tests in 1977. Initial tests in
March showed 0.1109, 0.1067 and 0.111 gr/dscf
with an average emission rate of 0.1096 gr/dscf,
37 percent above the standard. CE Maguire
then made some operating modifications (details
are not clear) and the unit was retested in May.
Test results were 0.0872, 0.0667, and 0.0780 gr/dscf
5-7
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with an average of 0.0773 which is 3 percent below the
standard. A summary by CE Maguire of the same test
results shows 0.0707 gr/dscf.
The use of a scrubber at Pawtucket was based upon easy avail- ',
ability of water facilities, enhanced gas pollutant removal, and low
initial capital costs. Another furnace will be equipped with a ven-
turi scrubber designed for 40- to 45-inch water guage pressure drop.
The results discussed in the previous paragraphs indicate that
venturi scrubbers for control of municipal waste particulate emis-
sions may involve considerable risk of nonattainment of the current
NSPS. The Pawtucket facility venturi scrubber operates at pressure1
drops higher than original design to barely meet the standard of 0.18
grams/dscm (0.08 grains/dscf) at 12 percent C02. One possible
factor may be that far more small particles are generated by incin-
eration than originally believed. The amount of particulate matter
below 2 microns from tested facilities has been reported to be
between 13.5 and 40 percent by weight. The effectiveness of venturi
scrubbing is theoretically proportional to the energy or pressure
drop, and inversely proportional to particle size. If the standard
is made stricter, e.g., 0.11 grams/dscm (0.05 grains/dscf),
applications of venturi scrubbers to new incinerators will involve
higher capital investment for draft fans and higher operating costs
that may make this technology infeasible economically when compared
with ESP or baghouse.
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5.1.3 Baghouse Results
Since 1971, only the East Bridgewater, Massachusetts facility
has been tested with a fabric filter control device. In 1975 that
facility tested at 0.054 grams/dscm (0.024 grains/dscf) at 12 percent
C02, well below the Massachusetts standard of 0.11 grams/dscm (0.05
grains/dscf) at 12 percent CC^. However, problems of bag and bag-
house corrosion and periodic high opacity observations have persis-
ted. A resource recovery system serving the City of Brockton and
surrounding towns is currently in the startup mode and may eventually
replace the incinerator facility.
A 9000-acfm pilot facility was recently used to evaluate several
types of filter bags as control media from a 135,000-lb/hr refuse-
fired boiler (Mycock, 1978). Removal efficiencies of greater than
99.8 percent were achieved when operating at air-to-cloth ratios of 6
to 1 or less. For the short testing period, no wear problems were
encountered. It should be pointed out that the input particle size
distribution was 13 percent less than 2 microns by weight, which is
on the low side of the 10 to 40 percent range.
Currently, Framingham, Massachusetts is the only other municipal
incinerator facility with a fabric filter control system. The spec-
ially coated bags are designed to prevent deterioration and overall
design capability is 0.07 gramsi/dscm (0.03 grains/dscf) at 12 percent
C02» This facility should be starting up in November 1978.
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5.2 Summary of Test Result Implications
The test results to date on existing and new facilities indicate
that a standard of 0.11 grams/dscm (0.05 grains/dscf) is technologi-
cally feasbile through the use of appropriately designed ESPs. This
stringent standard would affect every state except Delaware, Nevada,
Massachusetts, Maryland and Illinois where there are standards more
stringent than the current 0.08 grains/dscf at 12 percent C02 for
large incinerators. Such a standard would likely rule out scrubbers
as the primary equipment for particulate removal. Due to maintenance
problems, fabric filters have not been proven as a viable control
system, although they have demonstrated high-efficiency removal on an
experimental basis.
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6.0 FINDINGS AND RECOMMENDATIONS
The primary objective of this report has been to assess the need
for revision of the existing NSPS for municipal solid waste incinera-
tion and to describe any new developments that -have occurred since
the standard was promulgated in 1971. The findings and recommenda-
tions developed in these areas are presented below.
6.1 Findings
6.1.1 Incinerator Developments
• Between 1972 and 1977 the number of incinerator facilities
has been reduced from 193 to 103 with an accompanying capac-
ity drop of 40 percent to about 36,000 Mg/day (40,000 tons/-
day). During that time only five new facilities were identi-'
fied as being built and operating.
• A new development since 1971 is the increase in energy and
resource recovery from municipal waste. As a result, solid
waste is now being processed to a fuel—like substance and
burned either in on-site boilers or as a substitute or addi-
tion to traditional fuels in off-site boilers or other pro-
cessing units. Installed and under-construction capacity of
these units is about 27,000 Mg/day (30,000 tons/day) or about
three-fourths of current installed incinerator capacity.
6.1.2 Process Emission Control Technology
• The current best demonstrated control technology, the ESP,
has proven performance as well or better than envisioned in
1971 when the standard of 0.18 grams/dscm (0.08 grains/dscf)
at 12 percent C02 was promulgated.
• Two facilities with ESP control, in Massachusetts and
Maryland, successfully met emission standards of 0.11 grams/
dscm (0.05 grains/dscf) at 12 percent C02 and 0.07 grams/
dscm (0.03 grains/dscf) at 12 percent C02, respectively.
Seven other ESP test results were below. 0.11 grams/dscm (0.05
grains/dscf) at 12 percent C02-
• The use of venturi scrubbers for particulate matter control,
has not been as successful in meeting the NSPS and, because
of experience with corrosion and increasing energy costs, use
6-1
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of these scrubbers will likely decrease. Only one incinera-
tor operating with a venturi scrubber is meeting the NSPS,
and this unit has a new control device operating with a
relatively high pressure drop (35 to 40 inches water guage).
• Theoretically, baghouses have the highest removal efficiency
potential of any of the devices used to date. However, only
one incinerator in the U.S. has operated with a baghouse. :
The facility met with mixed success due to corrosion problems
associated with the bags and baghouse as well as apparent
periods of high emissions. An experimental pilot unit was
operated successfully. Further experience is required before
baghouses can be considered the best adequately demonstrated
technology.
6.1.3 Opacity Standard
• Every state except Illinois, Indiana and Delaware has a muni-
cipal solid waste incineration opacity standard of 20 percent
(Ringlemann No. 1). Illinois and Indiana have opacity stan-
dards of 30 and 40 percent, respectively; and Delaware has no
standard. The rationale for not including an opacity stan-
dard in the NSPS was the inability to define a correlation1
between opacity and particulate concentrations from several
tested facilities.
6.1.4 Coincineration with Sewage Sludge
• Various possibilities exist for incinerating municipal solid
waste and sewage sludge. There is currently no explicit
statement in either Subparts E or 0 that covers the appropri-
ate standard to be used for incinerators jointly burning
both types of waste.
6.2 Recommendations ;
6.2.1 Revision of the Standard
At this time there appears to be sufficient evidence to recom-:
mend development of a revised NSPS standard possibly to reflect a
more stringent emission level and an opacity standard. In ..this
development, data should be obtained and consideration given to the
need for establishing specific limitations on lead and cadmium
6-2
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emissions,
The rationale for these changes is based on the following
considerations:
• The best demonstrated control technology, the ESP, is being
used on most incinerators to meet NSPS and local standards.
• ESPs have been demonstrated to be capable of meeting the
Massachusetts and Maryland standards of 0.11 grams/dscm (0.05
grains/dscf) at 12 percent C02 and 0.07 grams/dscm (0.03
grains/dscf) at 12 percent C02, respectively.
• Opacity standards of 20 percent are currently in force for
new incinerators in almost every state. The usefulness of
opacity standards is the ability to identify excess emission
levels without requiring extensive stack testing to indicate
noncompliance.
• Cadmium and lead concentrations are reported to represent 0.4
percent and 11.0 percent, respectively, of the respirable
particulate emissions from one scrubber-controlled
incinerator.
6.2.2 Definitions
• Clarification is required for defining the applicable NSPS
standard when sludge and solid waste are jointly incinerated.
A table similar to Table 3-1 would be helpful in defining
when 40 CFR 60 Subpart E, Subpart 0, or a proration of both
is required. It is further suggested that the proration
scheme currently employed for joint incineration be avoided,
if possible, by explicitly including types of facilities in
both Subpart E and Subpart 0.
• Solid waste resource recovery systems are becoming^
increasingly popular and combustible wastes are being
processed into a homogeneous type fuel for use in boilers
or industrial processes. Whole facilities are being plan-
ned and are under construction for the explicit purpose
of generating electricity from steam produced by burning
processed refuse. These facilities would not be subject
to Subpart D which covers electrical generation from fos-
sil fuel. It is recommended that an NSPS be considered
to cover this category of refuse disposal.
6.2.3 Research Needs
• Given the relatively poor performance of scrubbers to date
and the developing baghouse technology, it is recommended
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that a research program to investigate the relationships
between waste input composition, particle size distributions,
and scrubber and baghouse operations be instituted at several
facilities to determine more precise design parameters for
these control techniques. .
Limited data are available on the metal and gaseous compo-
nents of emissions. It is recommended that research in this
area be continued.
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7.0 REFERENCES
Bozeka, C., 1976. Nashville Incinerator Performance Tests. 1976
National Waste Processing Conference, ASME, 1976.
Bump, R., 1976. The Use of Electrostatic Precipitators on Municipal
Incinerators in Recent Years. 1976 National Waste Processing
Conference, ASME, 1976.
Code of Federal Regulations, 1978. Subpart E - Standards of
Performance for Incinerators. 40 CFR 60. U.S. Govvernment
Printing Office, Washington, D.C.
Code of Federal Regulations, 1978. Subpart 0 - Standard of
Performance for Sewage Treatment Plants. 40 CFR 60. U.S.
Government Printing Office, Washington, D.C.
Environmental Reporter, 1978. State Air Laws. The Bureau of
National Affairs, Inc., Washington, D.C.
Farmer, J., 1978. Letter to R. Hanna, Department of Environmental
Conservation, State of Alaska from U.S. Environmental Protection
Agency.
Federal Register, November 10, 1977. Part 60 - Standards of
Performance for New Stationary Sources - Amendment to Subpart 0:
Sewage Sludge Incinerators. 42FR58521.
Hall, R. and Capone, S., 1978. Study of Effectiveness of Wet
Scrubber-Equipped New Municipal Incinerators - Phase I Draft
Final Report. Prepared for U.S. Environmental Protection
Agency, Technology Division, GCA-TR-78-40G, Bedford, Mass.
Hopper, T., 1977. Municipal Incinerator Enforcement Manual. The
Research Corporation of New England, Wethersfield, Conn.
Prepared for U.S. Environmental Protection Agency. EPA-340/1-
76-013.
Jacko, R. and Neuendorf, D., 1977. Trace Metal Particulate Emission
Test Results from a Number of Industrial and Municipal Point
Sources. Journal of Air Pollution Control Association, Vol. 27,
No. 10, October, 1977.
Jahnke, J., Cheney, J., Rollins, R., and Fortune, C., 1977. A
Research Study of Gaseous Emissions From a Municipal Incinera-
tor. Journal of Air Pollution Control Association, Vol. 27,
No. 8.
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Mycock, J., 1978. A Plot Plant Study of Various Filter Media Applied
to Refuse Boiler. This Symposium on Fabric Filters for Parti-
culate Collection. EPA-600/7-78-087. Tuscon, Ariz.,
December 5, 1977.
Smith, E., 1974. Municipal Incinerator Emissions - Current Know-
ledge. Recent Advances in Air Pollution Control. AICHE
Symposium Series, Vol. 70, No. 137.
St. Glair, C., 1978. Resource Recovery Update. Pollution Engineer-
ing, Vol. 11, No. 7.
Trenholm, 1978. Personal Communication. U.S. Environmental
Protection Agency, Durham, N.C.
U.S. Environmental Protection Agency, 1971. Background Information
for Proposed New Source Performance Standards. Office of Air
Programs, Research Triangle Park, Durham, N.C. :
U.S. Environmental Protection Agency, 1977. Compilation of Air
Pollutant Emission Factors. Second Edition, AP-42. Office of
Air Quality Planning and Standards, Research Triangle Park, N.C.
U.S. Environmental Protection Agency, 1978. 1975 National Emissions
Report. National Emissions Data System of the,Aerometrie and
Emissions Reporting System. EPA-450/2-78-020. Office of Air
Planning and Standards, Research Triangle Park, N.C.
U.S. Environmental Protection Agency, 1978a. Health Assessment
Document for Cadmium. External Review Draft No. 1, May.
U.S. Environmental Protection Agency, 1978b. Atmospheric Cadmium:
Population Exposure Analysis. Draft, March.
U.S. Environmental Protection Agency, 1978c. Sources of Atmospheric
Cadmium. Draft, February.
U.S. Environmental Protection Agency, 1978d. Carcinogen Assessment
Group's^Assessment of Carcinogenic Risk from Population Exposure
to Cadmium in the Ambient Air. External Review Draft, May.
Watson, J., L. Duncan, E. Keitz, and K. Brooks, 1978. Regional Views
of NSPS for Selected Categories. MTR-7772. MITRE Corporation,
McLean, Va.
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• ' ' TECHNICAL REPORT DATA
f . (Please read Instructions on the reverse before completing}
1 REPORT NO. 2.
• EPA-450/3-79-009
1. TITLE AND SUBTITLE
• 'A Review of Standards of Performance for New
• Stationary Sources - Incinerators
H. AUTHOR(S)
1 Richard M. Hel'fand
1. PERFORMING ORGANIZATION NAME AND ADDRESS
I Metrek Division of the MITRE Corporation
1 1820 Dolley Madison Boulevard
• Me Lean, VA 22102
2. SPONSORING AGENCY NAME AND ADDRESS
DAA for Air Quality Planning and Standards
Office of Air, Noise, and Radiation
U. S. Environmental Protection Agency
Research Triangle Park, NC 27711
3. RECIPIENT'S ACCESSION NO.
5. REPORT DATE
March 1979
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
MTR-7983
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-02-2526
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
EPA 200/04
5. SUPPLEMENTARY NOTES
6. ABSTRACT
This report reviews the current Standards of Performance for New Stationary
Sources: Subpart E - Incinerators. It includes a summary of the current
standards, the status of applicable control technology, and the ability of
incinerators to meet the current standards. Compliance test results are
analyzed and recommendations are made for possible modifications to the
standard. Information used in this report is based upon data available as
.of November 1978. -
17- KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
18. DISTRIBUTION STATEMENT
1 Release Unlimited
b. IDENTIFIERS/OPEN ENDED TERMS
19. SECURITY CLASS (This Report}
Unclassified
20. SECURITY CLASS (This page}
Unclassified
c. cos ATI Field/Group
13B
21. NO. OF PAGES
6U
22. PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION is OBSOLETE
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