&EPA
United States
Environmental Protection
Agency
Offic of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EPA-450/2-79-010
March 1978
Air
A Review of Standards
of Performance for New
Stationary Sources -
Sewage Sludge
Incinerators
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EPA-450/3-79-010
A Review of Standards
of Performance for New
Stationary Sources -
Sewage Sludge 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 Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
March 1979
-------
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-450/3-79-010
11
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ABSTRACT
This report reviews the current Standards of Performance for
New Stationary Sources: Subpart 0 - Sewage Sludge Incinerators.
It includes a summary of the current standards, the status of
applicable control technology, and the ability of sewage sludge
incinerators to meet current standards. Compliance test results
are analyzed and a recommendation made to retain the current
standard. Information used in this report is based upon data avail-
able as of November 1978.
iii
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TABLE OF CONTENTS
PAGE
LIST OF ILLUSTRATIONS '-rii
LIST OF TABLES viii
1.0 EXECUTIVE SUMMARY 1-1
1.1 Best Demonstrated Control Technology 1-1
1.2 Current Particulate Matter Levels Achievable with
Best Demonstrated Control Technology 1-2
1.3 Opacity Standard 1-2
1.4 Coincineration with Municipal Refuse 1-3
2.0 INTRODUCTION 2-1
3.0 CURRENT STANDARDS FOR SEWAGE SLUDGE INCINERATORS 3-1
3.1 Background Information 3-1
3.2 Facilities Affected 3-1
3.3 Pollutants Controlled 3-2
3.4 Monitoring and Testing Requirements 3-3
3.5 Applicability of NSPS to Coincineration of Municipal
Solid Waste with Municipal Sewage Sludge 3-4
3.6 State Regulations 3-9
4.0 STATUS OF CONTROL TECHNOLOGY 4-1
4.1 Status of Sewage Sludge Incinerators 4-1
4.1.1 Number and Geographic Distribution 4-1
4.1.2 National Emissions Summary and Projections 4-3
4.1.3 Municipal Sludge Incineration Trends 4-5
4.2 Sludge Incineration Process 4-6
4.2.1 Multiple Hearth Incineration 4-8
4.2.2 Fluidized Bed Combustion 4-13
4.2.3 Other Incinerator Processes 4-15
4.3 Emissions from Sewage Sludge Incinerators 4-16
4.3.1 Particulate Matter 4-16
4.3.2 Other Pollutants 4-19
5.0 INDICATIONS FROM TEST RESULTS 5-1
5.1 Analysis of NSPS Test Results 5-1
5.1.1 Scrubber Pressure Drop Versus Emissions 5-3
5.1.2 Emissions on a Volume Versus Mass Basis 5-7
5.1.3 Particulate Emissions Analysis Summary 5-14
v
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TABLE OF CONTENTS (Concluded)
Page
5.2 Opacity Measurements 5-15
5.3 Mercury Levels 5-15
6.0 FINDINGS AND RECOMMENDATIONS 6-1
6.1 Findings 6-1
6.1.1 Incinerator Developments Since 1973 6-1
6.1.2 Process Emissions and Control Technology 6-2
6.1.3 Opacity Standard 6-3
6.1.4 Coinclneration with Refuse 6-3
6.1.5 State Standards 6-3
6.2 Recommendations 6-3
6.2.1 Revision of the Standard 6-3
6.2.2 Definitions 6-4
6.2.3 Research Needs 6-4
7.0 REFERENCES 7-1
vi
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LIST OF ILLUSTRATIONS
Figure Number Page
3-1 Interpretation of Coincineration Standard
when Total Waste is Greater than 50 tons/
day 3-3
4-1 Sewage Sludge Incinerator Units 4-2
4-2 Geographic Distribution of Sewage Sludge
Incinerators Proposed, Under Construction,
or in Operation 4-4
4-3 Generic Sludge Incineration System
Description 4-7
4-4 Auxiliary Energy Requirements as a
Function of Moisture and Volatile Matter 4-9
4-5 Cross Section of a Typical Multiple
Hearth Incinerator 4-11
4-6 Multiple Hearth Process Zones 4-12
4-7 Fluidized Bed System with Air Preheater 4-14
5-1 Emissions Versus Scrubber Pressure Drop 5-4
5-2 Emissions Versus Scrubber Pressure Drop
in a Multiple Hearth Incinerator 5-6
5-3 Summary of 1973 Test Results Used for
Setting NSPS 5-8
5-4 Emissions on a Mass Versus Volume Basis:
Low Sludge Solids A 5-9
5-5 Emissions on a Mass Versus Volume Basis:
High Sludge Solids 5-11
5-6 Emissions Versus Sludge Moisture Content
in a Multiple Hearth Incinerator 5-13
vii
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LIST OF TABLES
Table Number Page
3-1 Applicability of 40 CFR 60 for
Coincineration with Sewage Sludge 3-6
3-2 Classification of Incinerator Waste 3-10
4-1 Uncontrolled Emission Factors from
Sludge Incineration 4-17
5-1 Sludge Incinerator Test Results 5-2
viii
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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 0.65 kg/Mg (1.3 Ib/ton) dry
sludge input and the opacity standard of 20 percent for the incinera-
tion of sewage sludge (Subpart 0, 40 CFR 60). This review is given
in terms of developments in technology and issues that have developed
since the standard was proposed in 1973. Possible revisions to the
standard are discussed in the light of compliance test data available
since that time. The following paragraphs summarize the results of
the analysis as well as recommendations for future action.
1.1 Best Demonstrated Control Technology
Particulate matter from the inert material in sludge is present
in the flue gas of sewage sludge incinerators. Uncontrolled emissions
may vary from as low as 4 kg/Mg (8 Ib/ton) dry sludge input to as
high as 110 kg/Mg (220 Ib/ton) dry sludge input depending upon the
incinerator type and the sludge composition (e.g., percent volatile
solids, percent moisture, and source treatment). While some type of
scrubber is universally used to control emissions, the analysis of
test results does not show a clear-cut relationship between a par-
ticular technology (e.g., venturi scrubber) and the ability to comply
with the standard. Rather, both the facility type and input sludge
composition are equally important considerations as the large range
in uncontrolled emissions factors indicates. The pressure drops in
various successful scrubber configurations range from 7 to 35 in.
1-1
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WG with a mean of 20 in. WG. These configurations included three-
stage perforated plate impingement scrubbers operating at 6 to 9 in.
WG and venturi scrubbers, or venturi scrubbers in series with various
impingement plate scrubbers operating in the 10 to 35 in. WG range.
1.2 Current Particulate Matter Levels Achievable with Best
Demonstrated Control Technology
Test results since 1974 for 26 facilities indicate that scrub-
ber controlled incinerators can comply with the NSPS. The average
emission from all tests was 0.6 + 0.35 kg/Mg (1.2 + 0.70 Ib/ton) dry
sludge input. When one obviously underdesigned facility and three
known non-NSPS tests were deleted the average emission were 0*45 +
0.17 kg/Mg (0.91 + 0.33 Ib/ton) dry sludge input or about 25 percent
below the standard.
Experimental data and some of the tested units indicate that
incinerators burning sludge below 20 percent solids may have diffi-
culty complying with the NSPS. Because combustion air requirements
per unit of dry sludge increase with increasing sludge moisture,
stack concentrations of 0.02 grams/dscm (0.01 grains/dscf) or less
may be needed. For this reason, and because of the wide variations
encountered in sludge and incinerator characteristics, it is recom-
mended that the NSPS level for particulate emissions not be changed.
1.3 Opacity Standard
Opacity levels from successful emissions tests never exceeded 15
percent and were most often either 0 or 5 percent. These results are
1-2
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similar to those found when the standard was first proposed as a 10
percent value with exceptions allowed during 2 min. of a 60 min.
test cycle. This standard was changed to 20 percent with no
exemptions except during startup, shutdown, or malfunctions. The
current data indicate that the rationale used to arrive at the 20
percent opacity level still applies.
1.4 Coincineration with Municipal Refuse
Various possibilities exist for incinerating municipal solid
waste and sewage sludge. There is currently no explicit statement in
either Subpart 0 or Subpart E (Standards of Performance for Incinera-
tors) that covers the appropriate standard to be used for incinera-
tors jointly burning both types of waste. It is suggested that
consideration be given to revising both Subparts E and 0 to cover
this situation.
1-3
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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 such standards following the procedure
required 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 Subpart 0, Standards of Performance for Sewage Treatment
Plants.
The main purpose of this report is to review the current sewage
sludge incineration particulate matter and opacity standard and to
assess the need for revision on the basis of developments that have
occurred or are expected to occur in the near future. This report
addresses the following issues:
1. A review of the definition of the present standard.
2. A discussion of the status -of. sewage sludge incineration
and the status of applicable control technology.
3. An analysis of particulate matter and opacity test
results and review of level of performance of best
demonstrated control technology for emission control.
Based on the information contained in this report, conclusions
are presented and specific recommendations are made with respect to
changes in the NSPS.
2-1
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3.0 CURRENT STANDARDS FOR SEWAGE SLUDGE INCINERATORS
3.1 Background Information
Prior to the promulgation of the NSPS in 1974, most sewage
sludge incinerators (SSI) utilized low pressure scrubbers (2 to 8
in. WG) to reduce emissions to the atmosphere (Balakrishman, et al.,
1970). These scrubbers were designed to meet state and local stan-
dards that were on the order of 0.2 to 0.9 grams/dry standard cubic
meter (dscm) or 0.1 to 0.4 grains/dry standard cubic foot (dscf) at
50 percent excess air. Incineration standards, for the most part,
reflected general incineration of all types with emphasis on munici-
pal solid waste. A separate standard for sewage sludge incineration
emissions was unusual. Control efficiencies, based on an uncontrolled
rate of 2.1 grams/dscm (0.9 grains/dscf) were between 50 and 90 per-
cent (EPA, 1973).
Testing was performed at three relatively well controlled
multiple-hearth incinerators and two fluidized bed reactors prior to
proposal of the standard in 1973 (EPA, 1973). One of the fluidized-
bed reactors was controlled by a venturi scrubber operating at 18
in. WG, while .the other incinerators were controlled by low pressure
impingement type scrubbers. Based upon these test results the stan-
dard was proposed and promulgated, as discussed in the following
paragraphs.
3.2 Facilities Affected
The NSPS promulgated as Subpart 0, Standards of Performance for
Sewage Treatment Plants, applies to incinerators built or modified
3-1
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after June 11, 1973. The Standard, as amended November 10, 1977,
defines an affected facility as any Incinerator that burns wastes
containing more than 10 percent sewage sludge (dry basis) produced
by municipal sewage treatment plants or charges more than 1000 kg
(2205 lb)/day municipal sewage sludge (dry basis) (42 FR 58520). If
a question exists, the owner/operator of a sewage sludge incinerator
may apply to the Administrator of EPA for a determination of whether
or not his facility is an affected facility.
A facility is considered to have commenced construction or modi-
fication on the date that the owner or operator has undertaken a con-
tinuous program of construction. This definition Includes the time
that a contractual agreement has been signed to undertake and com-
plete, within a reasonable time, a continuous program of construction
or modification. An existing facility modification includes any
changes in the physical plant or operations that will increase the
quantity of particulate matter emitted.
3.3 Pollutants Controlled
The NSPS for sewage sludge prohibits the discharge of particu-
late matter at a rate greater than 0.65 grams/kg of dry sludge input
(1.30 Ib/ton) and prohibits the discharge of any gases exhibiting 20
percent opacity or greater.
This is a change from the original proposed standards of 0.07
grams/dscm (0.031 grains/dscf) and less than 10 percent opacity. The
proposed standard was changed from a concentration to a mass basis
3-2
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because EPA felt that the determination of combustion air as opposed
to dilution air is particularly difficult due to the variable center
shaft and rabble arm cooling air designed into multiple hearth incin-
erators and could lead to unacceptable degrees of error (EPA, 1974).
The proposed opacity standard was changed from 10 to 20 percent
because: (1) 10 percent was too restrictive, (2) new regulations
provided exemptions during startup, shutdown, and malfunction, and
(3) 10 percent opacity was not consistent with the new mass emission
limit (EPA, 1974). A proposed opacity exemption of 2 min in any 1 hr
was also deleted in the promulgated standard because reevaluation of
data and analysis of new data indicated there was no basis for addi-
tional time exemptions.
3.4 Monitoring and Testing Requirements
A flow measuring device must be installed, calibrated, main-
tained, and operated at all affected facilities. The purpose of
this device is to determine the mass or volume of sludge charged to
the incinerator. The NSPS requires that the flow measuring device
have an accuracy of ±5 percent over its operating range. If munici-
pal solid waste is incinerated with sewage sludge, a weighing device
for the solid waste is required with a similar +5 percent accuracy.
In addition to the flow measuring device, the owner or operator
of a sludge incinerator is required to provide access to the sludge
charged so that a well-mixed representative grab sample can be ob-
tained. The grab sample is used to determine the dry sludge content
(total solids residue).
3-3
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The following EPA reference test methods are then used to deter-
mine compliance:
Method 1 - sample and velocity traverses
Method 2 - volumetric flow rate
Method 3 - gas analysis
Method 5 - concentraction of particulate matter and
associated moisture content
Additional procedures for reference method 5 require that the samp-
ling time for each run be at least 60 min and the sampling rate be
at least 0.015 dscm/min (0.53 dscf/min).
The dry sludge charging rate is determined from a grab sample
and data from the flow measuring device. The dry sludge content
(total solids residue) is determined in accordance with "2246 Method
for Solid and Semisolid Samples" (American Public Health Association,
1971) with the following exceptions:
1. Evaporating dishes are ignited to at least 103* rather than
550
2. The determination of volatile residue may be deleted
3. The quantity of dry sludge per unit sludge charged is deter-
mined in terms of either milligrams dry sludge/liter sludge
charged (pounds/cubic feet) or milligrams dry sludge/mil-
ligrams sludge charged (pounds/pound).
Compliance or noncompliance with the standard is then determined
by calculations presented in 40 CFR 60.154.
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
3-4
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scale in the U.S. (Sussman and Gershman, 1978). Where energy re-
sources 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 institu-
tional commonality of these wastes and advances in the preincinera-
tion 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.
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 CC>2
applies to the incineration of municipal solid waste in furnaces with
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 Ib/ton dry sludge), applies to any incinerator
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
^Special rules apply to communities of less than approximately 9000
persons. See the Federal Register (1977).
3-5
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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 Subparta 0 and E. Table 3-1 summarizes the current
rules that apply to solid waste and sewage sludge incineration
(Farmer, 1978).
The alternative for 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 muni-
cipal incineration standard of Subpart E from grams per dry standard
cubic meters (grains per dry standard cubic foot) at 12 percent 02
to grams per kilograms (pounds per ton) refuse input, or a
transformation of the sewage sludge standard (Subpart 0) from grams
per dry kilograms (pounds per dry ton) input to grams per dry
standard cubic meter at 12 percent C02- Such transformations are
dependent on the percent C02 in the flue gas stream, the
stoichiometric air requirements, excess air, the volume of combustion
products to required air, and the percent moisture 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
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TABLE 3-1
APPLICABILITY OF 40 CFR 60 FOR
COINCINERATION WITH SEWAGE SLUDGE
Sewage Sludge
(percent)
Municipal
Refuse
(percent)
Incinerator
Charging Rate
Applicable
Subpart
(40 CFR 60)
51-100
0-49
>50 Tons/Day Total Waste
Subpart 0 or
Proration of
0 and E
0-50
0
100
1-99
11-99
0-10
50-100
100
0
1-99
1-89
90-100
>50 Tons/Day Total Waste
£50 Tons /Day Municipal Refuse
Any Rate
£50 Tons/Day Total Wastes,
>1.1 Dry Tons /Day Sewage Sludge
£50 Tons/Day Total Wastes,
<1.1 Dry Tons /Day Sewage Sludge
£50 Tons/Day Total Wastes
<1.1 Dry Tons/Day Sewage Sludge
Subpart E
None
Subpart 0
Subpart 0
Subpart 0
None
Source: Fanner, 1978.
3-7
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Subpart E
u
09
O
0)
2
60
0.055
Subpart 0 - 0.03
Applicable Standard
so
Pereeat Sewage Sludge
I
100
50
Percent Municipal Refuse
100
FIGURE 3-1
INTERPRETATION OF COINCINERATION STANDARD
WHEN TOTAL WASTE IS GREATER THAN 50 TONS/ DAYS
3-8
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3.6 State Regulations
A survey of current state air quality control regulations was
performed to identify differences between the Federal NSPS for sewage
sludge incinerators and state regulations (Environmental Reporter,
1978). Of particular interest were the control levels specified by
the states as compared with the current NSPS of 0.65 grams/kg (1.3
Ib/ton) dry sludge input. The survey results are summarized as
follows:
Of the 22 states explicitly referencing NSPS for sewage
sludge incinerators, none differ from the Federal standard.
Maryland's NSPS for particulate emissions of 0.03 grains/dscf
at 12 percent C02 may be more stringent than the 1.3 Ib/dry
ton input standard. The remaining states either have stan-
dards less strict for new sewage sludge incinerators or have
general incineration standards that do not explicitly
reference sewage sludge. None of the states have explicit
standards for existing SSIs.
Of those states having general incineration standards, the
standard level, wording and description of the testing pro-
cedures indicate that the standards apply mainly to charac-
teristics associated with municipal incineration of solid
waste and not to the special case of SSIs.
No state has a standard for the joint incineration of mu-
nicipal sewage sludge and solid waste.
Many states use the categorization of waste given in Table
3-2 as adopted from the National Solid Wastes Management
Association (NSWMA) as a basis for emission standards for
each waste category. This categorization is incomplete in
that the sludge from municipal wastewater treatment is not
described in the NSWMA categorizations. It is, therefore,
difficult to identify what emission standard would be ap-
plied to operating an SSI within the state.
Many states have incinerator standards that require new
incinerators to be multichambered, operate at minimum tem-
peratures ranging from 1200°F to 1600°F, and have minimum
retention times of 0.3 seconds or greater. These standards
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TABLE 3-2
Type 0
(Trash)
Type 1
(Rubbish)
Type 2
(Refuse)
Type 3
(Garbage)
Type 4
(Human and
Animal
Remains)
Type 5
(By-Product
Waste)
Type 6
(Solid
By-Product
Waste)
CLASSIFICATION OF INCINERATOR WASTE
A mixture of highly combustible waste such as paper,
cardboard, cartons, wood boxes and combustible floor
sweepings from commercial and industrial activities.
The mixture may contain up to 10 percent by weight of
plastic bags, coated paper, laminated paper, treated
corrugated cardboard, oily rags and plastic or rubber
scraps. This type of waste contains approximately 10
percent moisture and 5 percent incombustible solids
and has a heating value of approximately 8500 Btu/lb
as fired.
A mixture of combustible waste such as paper, card-
board, wood scrap, foliage and combustible floor
sweepings, from domestic commercial and industrial
activities. The mixture may contain up to 20 percent
by weight of restaurant or cafeteria waste, but con-
tains little or no treated paper, plastic or rubber
wastes. This type of waste contains approximately 25
percent moisture and 10 percent incombustible solids
and has a heating value of approximately 6500 Btu/lb
as fired.
An approximately even mixture of rubbish and garbage
by weight. This type of waste is common to apartments
and residential homes. It consists of up to 50 per-
cent moisture and approximately 7 percent incombusti-
ble solids and has a heating value of approximately
4300 Btu/lb as fired.
Animal and vegetable wastes from restaurants, cafeter-
ias, hotels, hospitals, markets and the like. This
type of waste contains up to 70 percent moisture, up
to 5 percent incombustible solids and has a heating
value of approximately 2500 Btu/lb as fired.
Carcasses, organs and solid organic wastes from hospi-
tals, laboratories, abatoirs, animal pounds and simi-
lar sources, consisting of up to 85 percent incombus-
tible solids and having a heating value of approxi-
mately 1000 Btu/lb as fired.
Gaseous, liquid or semiliquid waste, such as tar,
paints, solvents, sludge, and fumes from Industrial
operations.
Rubber, plastics and wood waste from industrial oper-
ations and all salvage operations.
3-10
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appear to be written for municipal solid waste disposal in-
cinerators but, as discussed above, may also apply to SSIs.
Every state but Illinois and Indiana has an opacity standard
of 20 percent for new sewage sludge incinerators. The Illi-
nois standard is 30 percent and the Indiana standard is 40
percent.
In summary, only Maryland has a standard for sewage sludge in-
cinerators that is more stringent than the NSPS. Many states do not
have standards that explicitly recognize SSI as a different source
capacity from other incineration processes. A number of states have
equipment and minimum temperature standards that apply to general
incineration processes including sewage sludge. It also appears that
several states depend on the NSWMA waste categorization for applica-
tion of incineration emission standards, and municipal sludge is not
included in the NSWMA categories.
3-11
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4.0 STATUS OF CONTROL TECHNOLOGY
4.1 Status of Municipal Sludge Incinerators
4.1.1 Number and Geographic Distribution
Since 1934 approximately 400 municipal sludge incinerator units*
have been built, are under construction, or have been proposed. Fig-
ure 4-1 indicates that the large growth of Municipal Sewage Sludge
Incinerators (MSSIs) occurred In the 1967-1972 period and that in-
terest in this sludge reduction technique has continued today.
A recent survey of sludge incinerators Indicates that about half
of those installed before 1950, 70 percent of those Installed between
1950 and 1969, and 85 percent of those installed between 1970 and the
present are still in service (Gordlan Associates, 1978). Using these
proportions with the distribution shown in Figure 4-1 gives an esti-
mate of approximately 240 MSSIs presently in operation. A compila-
tion of incinerator units subject to the construction grants program
Indicated that 92 new units were either in the construction or plan-
ning stages in mid-1977 (EPA, 1977). A total of 23 MSSIs have been
identified as candidates for NSPS testing within the 1973-1978 time-
frame.
The majority of units in place are multiple hearth incinerators
(approximately 80 percent) with the remainder mostly fluidIzed bed
reactors. Fluldized bed reactors are relatively new with the first
*A unit is equivalent to a facility as defined in the NSPS. Many
municipalities have more than one facility (unit) at a single
location.
4-1
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I
ro
160
140
120
80
60
40
20
NSPS
Sources:
1934-36 1937-42 1943-48 1949-54 1955-60 1961-66 1967-72 1973-78 Proposed
or Under
Construction
Gordian Associates, 1978;
EPA, 1977
FIGURE 4-1
SEWAGE SLUDGE INCINERATOR UNITS
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reactor becoming operational in 1962. A very new sewage sludge in-
cineration technique involving electric (infrared) furnaces has been
demonstrated in two locations during the past 2 years. At least
eight more of these furnaces are planned or under construction.
The geographic distribution of sewage sludge incinerators is
shown in Figure 4-2. The major concentration of units is found in
the Northeast and upper Midwest states, although 38 states have, or
are planning, at least one facility.
4.1.2 National Emissions Summary and Projections
It is estimated that approximately 5 million Mg (5.5 million
tons) dry sludge/year are generated by municipal wastewater treatment
plants (EPA, 1978). About 2.3 million Mg (2.5 million tons) of this
sludge are incinerated, or approximately 45 percent of the total
(Gordian Associates, 1978). The resultant controlled particulate
emissions from municipal sludge incineration are estimated to be 3800
Mg (4200 tons)/year or approximately 0.03 percent of total nationwide
particulates emitted annually.*
Projections have indicated that the generation of sludge from
municipal wastewater treatment plants may double in the next 10 years
due to environmental legislation calling for higher quality effluents
from wastewater treatment (EPA, 1978). If the proportion of this
*This is based on an emission factor of 1.5 kg/Mg (3 Ib/ton) dry
sludge input in AP-42 (EPA, 1977) and national particulate emis-
sions of 12.5 x 106 Mg/yr (13.8 x 106 tons/yr) given in the EPA
National Emissions Inventory (EPA, 1978a).
4-3
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R.I. 5(4)
Md. 7(0)
PR. 4(4)
first numbers are total units
in operation, under construction,
or planned. Numbers in parenthe-
ses are units planned or under
construction.
Sources: EPA, 1977; Gordian Associates,
1977; MITRE, 1978.
FIGURE 4-2
GEOGRAPHIC DISTRIBUTION OF SEWAGE SLUDGE INCINERATORS
PROPOSED, UNDER CONSTRUCTION, OR IN OPERATION
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sludge that is incinerated remains the same (45 percent), and if the
additional sludge were incinerated in facilities subject to the cur-
rent NSPS, there would be an increase to about 5500 Mg (6000 tons) of
particulate matter emitted per year.
4.1.3 Municipal Sludge Incineration Trends
In mid-1973 EPA predicted that:
Over the next few years, it is estimated that 70 new
municipal sewage sludge incinerators will be constructed
annually in the United States. Factors such as the avail-
ability of alternative methods of sludge disposal will
have a significant effect on the actual rate of construc-
tion. ...(EPA, 1973)
This prediction was made just prior to the oil embargo and the
subsequent increase in fuel oil costs and the growing national empha-
sis on energy conservation. The data indicate that many communities
switched sludge disposal strategies away from incineration due to the
energy crises, since a total of about 110 units have been identified
as being built, under construction, or planned in the 5-year period
since that time.
As a result of several interacting factors such as energy, land,
equipment costs and the increasing amounts of sludge being generated
due to improved wastewater treatment facilities, the most economical
sludge disposal technique has become difficult to determine. As a
competing alternative, sludge incineration has undergone significant
changes, the most notable being the recovery and use of waste heat
generated in the incinerator. The use of waste heat to produce steam
for in-plant use, preheating combustion air, or heat treating sludge
4-5
-------
to improve dewatering characteristics is becoming common in almost
all designs suggested by manufacturers of incineration equipment.
In addition, the cost of fuel has increased the desirability of
autogeneous (self-sustaining) incineration which, in turn, has given
emphasis to improved sludge dewatering techniques that are necessary
to raise the relative energy content of the input sludge to a self-
sustaining level. Although relatively new in the United States, the
concept of using the refuse derived fuel from a solid waste resource
recovery facility as the fuel for sludge incineration has been tested
and is about to be implemented on a large scale basis in at least one
community (Duluth, Minnesota).
As a result of the above improvements in design, and the eco-
nomic or technical problems associated with land disposal in certain
locations, incineration has remained a viable technique for sludge
volume reduction as is indicated by the 92 units identified by EPA
as proposed or under construction.
4.2 Sludge Incineration Process*
The basic elements of sludge incinceration are shown schemat-
ically in Figure 4-3. An incinerator is usually part of a sludge
treatment system which includes sludge thickening, a dewater condi-
tioning system, a dewatering device (such as a vacuum filter, cen-
trifuge, or filter press), an incinerator feed system, air pollution
*Much of this section was extracted from "Process Design Manual for
Sludge Treatment and Disposal" (EPA, 1974a).
4-6
-------
I
-J
CONDITIONING
DEWATERING
ENERGY RECOVERY
THERMALLY CONDITION SLUDGE
t
STEAM
PREHEAT AIR
AIR AUXILIARY
FUEL
SLUDGE
FEED
COMBUSTIBLE
ELEMENTS
INERTS
MOISTURE
I
1 1
INCINERATOR
1
1
1
ASH
STACK GASES
^^H^^M «^^MBM
MOISTURE
EXCESS AIR
PARTICULATES
OTHER PRODUCTS OF
COMBUSTION
FIGURE 4-3
GENERIC SLUDGE INCINERATION SYSTEM DESCRIPTION
-------
control devices, ash handling facilities, and the related automatic
controls.
A primary consideration in the cost-effectiveness of sludge
incineration is the effect of sludge feed composition on auxiliary
fuel requirements. Other variables of importance are the type of
incinerator employed, excess air requirements, operating temperatures
necessary for odor control and other air pollution constraints. A
recent addition to the sludge incineration system is the capability
for energy recovery when a net heat gain is available.
Processed sludge (e.g., anaerobic digestion) and heat treatment
processes reduce the volatile content and increase the inert noncom-
bustible content with resultant lower fuel value for a sludge. As
a result, auxiliary fuel is required to sustain combustion in many
SSIs. Pretreatment methods such as chemical conditioning and dewa-
tering do result in substantial reduction of incineration fuel re-
quirements, but frequently they do so by creating increased energy
demands on other unit processes. Figure 4-4 indicates the general
relationship between auxiliary fuel requirements (in this case natu-
ral gas), moisture content, and volatile solid contents for a 10,000
Btu/lb volatile solids sludge. The use of a relatively wet sludge
(e.g., 80 percent moisture) can greatly increase fuel requirements
and the amount of air requiring cleaning.
4.2.1 Multiple Hearth Incineration
The multiple hearth furnace is the most widely used wastewater
sludge incinerator in the U.S. today, because it is simple, durable,
4-8
-------
1,600
^N
s
0)
^ 1,400
4J
S!
g 1,200
4J
O
I
CO
«d
O
1,000
800
600
400
200
Sluge heat content - 10,000 Btu/lb
volatile solids (V.S.)
75 76 77 78 79 80 81 82
Moisture Content of Feed (X)
83
FIGURE 4-4
AUXILIARY ENERGY REQUIREMENTS AS A FUNCTION
OF MOISTURE AND VOLATILE MATTER
4-9
-------
and has the flexibility of burning a wide variety of materials even
with fluctuations in the feed rate. A typical multiple hearth fur-
nace is shown in Figure 4-5. It consists of a circular steel shell
surrounding a number of solid refractory hearths and a central rotat-
ing shaft to which rabble arms are attached. Capacities of multiple
hearth furnaces vary from 91 to 3600 Kg/hr (200 to 8000 Ib/hr) of
dry sludge with operating temperatures ranging from 700°C to 1100°C
(1300°F to 2000°F). The dewatered sludge enters at the top through
a flapgate and proceeds downward through the furnace from the hearth
through the rotary action of the rabble arms. Since the furnace may
operate at temperatures up to 1100°C (2000°F), the central shaft and
rabble arms are effectively cooled by air supplied in regulated quan-
tity and pressure from a blower which discharges air into a housing
at the bottom of the shaft. The air may be discharged to the atmo-
sphere or returned to the bottom hearth of the furnace as preheated
air for combustion purposes.
The rabble arms provide mixing action as well as rotary and
downward movement of the sludge. The flow of combustion air is coun-
tercurrent to that of the sludge. Gas or oil burners are provided on
some of the hearths for furnishing heat for startup or supplemental
use as required. As shown in Figure 4-6, a multiple hearth sludge
furnace may generate gas temperatures exceeding 760°C (1500°F) in
the combustion zone. These gases sweep over the wet, cold sludge in
the drying zone and perform useful work by giving up a considerable
4-10
-------
COOLING AIR DISCHARGE
FLOATING DAMPER
SLUDGE INLET
FLUE GASES OUT
DRYING ZONE
COMBUSTION ZONE
COOLING ZONE
ASH DISCHARGE
RABBLE ARM
AT EACH HEARTH
COMBUSTION
'AIR RETURN
RABBLE ARM
DRIVE
F*>
COOLING AIR FAN
\
FIGURE 4-5
CROSS SECTION OF A TYPICAL MULTIPLE HEARTH INCINERATOR
4-11
-------
SLUDGE TEMPERATURE
AIR TEMPERATURE
FIGURE 4-6
MULTIPLE HEARTH PROCESS ZONES
4-12
-------
portion of their heat for evaporation of moisture. In this heat
exchange, the gas temperature may drop to as low as 260°C (500°F)
at the gas outlet. But while this exchange of heat evaporates an
important percentage of sludge moisture, it does not raise the sludge
temperature higher than about 71°C (160°F) because the evaporation
of water cools the mass it leaves. When properly operating (e.g.,
hearth temperatures are properly maintained) no significant quantity
of odoriferous matter is distilled, and exhaust gases need not be
raised in temperature in an afterburner to destroy odors. Distil-
lation of odoriferous material from sludge containing 75 percent
moisture should not occur until 80 to 90 percent of the water has
been driven off and by this time, the sludge is down far enough in
the incinerator to encounter gases hot enough to burn much of the
odoriferous materials.
To protect against odors during nonoptimum operation, some
states require incinerator installations to provide high temperature
afterburning of the stack gases. Gases are conveyed to a chamber
where the temperature is raised by burning auxiliary fuel in direct
contact with the gases before venting to the atmosphere.
4.2.2 Fluidized Bed Combustion
Fluidized bed combustion is a second technique for incinerating
municipal sludge. A typical section of a fluid bed reactor used for
combustion of wastewater sludges is shown in Figure 4-7. The fluid-
ized bed incinerator is a vertical cylindrical vessel with a grid in
4-13
-------
Fluidized Sand
Sludge Inlet
Hot gas in
1500°F
REACTOR
AIR
PREHEATER
Gas out
To scrubber
FIGURE 4-7
FLUIDIZED BED SYSTEM WITH AIR PREHEATER
4-14
-------
the lower section to support a sandbed. Dewatered sludge is injected
above the grid and combustion air flows upward and fluidizes the mix-
ture of hot sand and sludge resulting in fine mixing of sludge and
air. Supplemental fuel can be supplied by burners above or below the
grid and preheating of the combustion air is often performed. In
essence, the reactor is a single chamber unit where both moisture
evaporation and combustion occur at 1400° to 1500°F in either the
dense or dilute phases of the sandbed. All the combusion gases pass
through the combustion zone with residence times of several seconds.
All the resulting ash is carried out of the top with combustion
exhaust and is removed by air pollution control devices. Excess air
requirements, uusally between 20 and 50 percent, are less than those
of the multiple hearth incinerator which operates with 50 to 75 per-
cent excess air.
The heat reservoir provided by the sandbed also enables reduced
startup times when the unit is shut down for relatively short periods
(overnight). This is advantageous to facilities with intermittent
incineration requirements. The cool-down time for some maintenance
activities is also shorter in fluidized bed incinerators than in
multiple hearths.
4.2.3 Other Incinerator Processes
Several other incinerator processes are in limited use, includ-
ing flash drying/incineration, cyclonic reactors, the rotary kiln,
and the wet oxidation method (this process does not produce flyash
4-15
-------
since relatively slow, low temperature, high pressure oxidation of ma-
terial is involved). The electric infrared furnace is a new process
that has been tested under the NSPS. The results of two tests using
this process are given in Section 5.1.
4.3 Emissions From Sewage Sludge Incinerators
4.3.1 Particulate Matter
Uncontrolled particulate emission rates from sludge inciner-
ators can vary considerably depending on the volatile solids and
moisture contents of the input sludge and the type of facility being
used. Fluidized bed reactors are designed to burn sludge in suspen-
sion with much of the ash to be carried out with the exhaust gas.
Multiple hearth incinerators have an 80 to 90 percent retention rate
of ash, although uncontrolled emissions are still higher than conven-
tional solid waste incinerators. Infrared incineration systems that
were recently tested had relatively low uncontrolled emission rates*
when compared with the first two techniques.*
Table 4-1 summarizes the limited data available on uncontrolled
particulate emissions. The fluidized bed emissions were from a
primary sludge with high volatile solid content. It is likely that
sludge resulting from anerobic treatment would tend to have more
inert matter than was indicated in the referenced study and therefore
would produce a higher emission factor.
*Indirect emissions resulting from the generation of electrical power
required to incinerate the sludge were not included in the emission
rates.
4-16
-------
TABLE 4-1
UNCONTROLLED EMISSION FACTORS FROM SLUDGE INCINERATION
Sludge Characteristics
Source
EPA, 1976
EPA, 1975
Petura, 1976
Liao & Pilat, 1972
Shirco, 1978
Kroneberger, 1978
Incinerator Type
All
Multiple Hearth
Fluidized Bed
Multiple Hearth
Fluidized Bed
Electric (Infrared)
Multiple Hearth
% Moisture
N.G.
N.G.
N.G.
67
75
85
80
% Solids
(% Ash/% Volatiles)
N.G.
N.G.
N.G.
33 (45/55)
25 (15/85)
15 (50/50)
15 (20/80)
20 (20/80)
25 (20/80)
Uncontrolled Emissions
Low
kg/Mg(lb/ton)
N.G.
N.G.
N.G.
45(90)
9 (18)a
N.G.
N.G.
N.G.
N.G.
Average
kg/Mg(lb/ton)
50(100)
17(33)
23(45)
75(150)
47(94)a
9(17)
61(122)
52(103)
41(82)
High
kg/Mg(lb/ton)
N.G.
N.G.
N.G.
110(220)
171(342)*
N.G.
N.G.
N.G.
N.G.
Values Corrected to 12% C02 from approximately 8% C02.
N.G.: Not Given.
-------
The EPA Sludge Design Manual estimates a value of 17 kg/Mg (33
Ib/ton) of dry sludge input in a multiple hearth furnace and 23 kg/Mg
(45 Ib/ton) of dry sludge input in a fludized bed incinerator (EPA,
1974). The document also states:
Particulate collection efficiencies of 96 to
97 percent will be required to meet the standard,
based on the above uncontrolled emissions rate ....
The uncontrolled emission values in the design manual appear
to be low if the basis is tons of dry sludge burned. Based upon the
results in Table 4-1, uncontrolled emissions from multiple hearth
incinerators are three to four times those given in the design man-
ual. Control efficiences of 98.5 to 99.5 percent would be required
to comply with the NSPS as shown by the equation:
ff _ , 1.3 Ib particulate/dry ton sludge
80 to 220 Ib particulate/dry ton sludge
4.3.1.1 Particle Size Distributions. Little experimental data
are available in the literature with respect to the particle size dis-
tribution of uncontrolled emissions entering control devices of sew-
age sludge incinerators. In a fluidized bed reactor more than 85 to
95 percent of the particles by weight were greater than 30 microns
(Liao and Pilat, 1972). These particles are relatively easy to con-
trol with low pressure drop scrubbers. With the NSPS requirement of
65 kg/Mg (1.3 Ib/ton) of dry sludge input, emission volume densities
of 0.009 to 0.071 grams/dscm (0.004 to 0.03 grains/dscf) have been
4-18
-------
observed after the gases have been passed through scrubbers operating
at 10 to 35 in. WG pressure drop (See Table 5-1). Based on these
results it is likely that at least 1 to 5 percent of the uncontrolled
particulate matter entering a scrubber from a sludge incinerator is
in the low micron and submicron range.
4.3.1.2 NSPS Control Techniques. Sludge incinerator controls
have historically involved the use of scrubber equipment. The most
obvious reasons for this are the readily available scrubber water
treatment facility (e.g., the sewage treatment plant) and the appar-
ent success to date of meeting the increasingly stringent standards
through scrubbing techniques. As removal requirements have in-
creased in stringency from 50 percent in the mid 1960s to the current
levels of 99 percent, the sophistication of the scrubbers has in-
creased. Common configurations used today include variable throat
venturi scrubbers in series with cyclonic mist eliminators, venturi
scrubbers in series with perforated-plate impingement type scrubbers,
or multiple series of perforated plate impingement scrubbers. Pres-
sure drops in these devices may range from 6 in. WG to as high as 35
in. WG. To overcome pressure losses draft fans are employed which
are sized to handle the designed pressure drops. There are no plants
operating in the U.S. at this time that employ baghouse or electro-
static precipitators for control purposes.
4.3.2 Other Pollutants
Mercury emissions from sewage sludge incinerators are explic-
itly controlled under the National Emissions Standards for Hazardous
4-19
-------
Pollutants (NESHAPS) section of the Code of Federal Regulations
(40 CFR 61.5). Mercury emissions are not to exceed 3200 grams/day.
This limit is based on maintaining a maximum average ambient mercury
concentration of 1 (JL grams/in^ over a 30-day period. As indicated in
Section 5.2, limited test data show that no facility approaches the
emission level of 3200 gram/day. Measurements taken by EPA's Office
of Air Programs to supporc a mercury emissions standard showed that
68 to 96 percent of the mercury was removed from the exhaust gases
(EPA, 1974). This high removal rate was verified independently in
another study that showed only 2 percent of the mercury in the in-
coming sludge appeared in the flue gases based on a complete mass
balance around a multiple hearth incinerator (Whitmore and Durfee,
1974).
EPA studies have shown that less than 15 percent of the lead
in input sludge appears in flue gases, while other field tests
have shown less than 1 percent of the input lead in the flue gases
(Kalinski, et al., 1975). However, in a recently reported result
from a set of four multiple hearth sludge incinerators with rela-
tively low pressure drop wet scrubbers (6 to 7 in. WG), as high
as 30 percent of the lead and cadmium fed to the incinerators was
discharged in the form of fine particulate matter after scrubbing
(Farrell et al., 1978). The report goes on to suggest that higher
scrubber pressure drops will likely achieve reductions in lead emis-
sions but may not reduce cadmium emissions sufficiently to prevent
excessive ground level concentrations.
4-20
-------
It has been generally recognized that the high temperatures
existing in incinerators could be utilized to destroy excess quanti-
ties of unwanted pesticides (EPA, 1975a). As an extension of this
concept, the Office of Solid Waste Management at EPA funded a study
to see if stocks of excess pesticides, such as DDT and 2,4,5-T,
could be destroyed by coincineration with sewage sludge in a multiple
hearth sludge incinerator at pesticide preparation concentrations of
2 to 5 percent (based on dry sludge weight). Very high destruction
efficiencies were verified in this study99.97 percent or higher in
the case of 2,4,5-T (Whitmore and Durfee, 1975).
The present EPA position with respect to polychlorinated bi-
phenyls (PCBs) does not require any particular test for sludges with
less than 25 ppm of PCBs and a performance test showing 95 percent
destruction when the PCB concentration is over 25 ppm (FR57420,
1977). Such destruction rates have been measured in tests sponsored
by EPA where the sewage sludge was "doped" by adding 50 ppm of an
easily identifiable PCB into the sludge; however, most municipal
sludges contain significantly less than 25 ppm of PCBs (Whitmore,
1977; Furr, 1976).
Measurements of the emissions of hydrocarbons and carbonyls
from sludge incineration have been made on two sludge incinerators
in the San Francisco Bay Area to assure compliance with stringent
emission limits of 25 ppm for both classes of organic compounds.
4-21
-------
Results showed emission levels significantly less than the 25 ppm
standards; 0.4 to 2.2 ppm for the hydrocarbons and 3.4 to 7.6 ppm for
the carbonyls (EPA, 1975a).
4-22
-------
5.0 INDICATIONS FROM TEST RESULTS
A survey of the literature and polls of EPA regional offices,
state agencies, and local facilities were performed to obtain test
data from new sewage sludge incinerators. In certain cases the
incinerators were put into operation after the date of the standard
proposal but construction was begun before the date of proposal.
Test data were included if the state or local standard was rela-
tively stringent and/or if the control level achieved was suffi-
cient for meeting the NSPS. In at least one instance a wastewater
treatment facility with an incinerator constructed after the
standard proposal date was given a permit to construct prior to
the proposal date. This facility was designed and is operating at
a less stringent level of control which is equivalent to the state
regulation (Schmidt, 1978).
In several instances only partial test results were available.
In these cases an attempt was made to estimate missing parameters
based upon known information in the test report and design data
obtained from manufacturers. These cases are Indicated by an E
prefix in Table 5-1.
5.1 Analysis of NSPS Test Results
The results of tests at 26 incinerators are summarized in
Table 5-1. As is evident from the data most facilities are meeting
the standard. The average of all tests results is 0.55 Kg/Mg (1.1
Ib/ton) dry sludge input with a standard deviation of 0.35 Kg/Mg
5-1
-------
TABLE 5-1
SLUDGE INCINERATOR TEST RESULTS
in
10
Type
MH8
MH
MH
MH
MH
MH
MH
MH
MH
MH
MH
MH
MH
FB8
MH
MH
MH
MH
MH
MH
MH
MH
ELh
EL
EL
FB
Location
Chicopee, Mass, fl
Chicopee, Mass. 12
East Fltchburg. Mass.
Manchester, N.H. fl
Manchester, N.H. 12
Merrlnack, N.H. fl
Merrlaack. N.H. f2
Upper Blackstone, Mass, fl
Upper Blackstone, Mass. f2
Upper Blackstone, Mass. t3
Erie, Pa. flf
Erie, Pa. f2f
Morrisvllle, Pa.
Tyrone, Pa.
HopeweU, Va.
Maryvllle, Tenn.
Granite City, 111.
Cincinnati, Ohio fl
Cincinnati, Ohio f2
Cincinnati. Ohio f3
Lawton, Okla.
Mission, Kane. f2
Piano, Tex. tl
Piano, Tex. 12
Richardson, Tex.
Lohgview, Wash.
Average z Std. Dev.
Input
(dry tons/
Date hour)
2/78
6/78
2/76
3/77
3/77
3/78
3/78
6/77
6/77
6/77
11/75
11/75
2/77
3/77
8/78
12/77
1/77
N.G. (76)
N.G. (76)
N.G. (76)
8/78
2/77
5/78
5/78
2/77
2/77
0.3
0.4
1.3
0.6
0.6
1.1
1.0
1.9
1.9
2.0
2.0^
2.0e
0.8
1.0
3.2
0.4
2.3e
2.9
2.6
2.4
0.6
0.8e
0.2
0.2
N.C.
1.1
1.4+.9
Percent
Solids
21
26
15-18
15
15
16
16
26
26
26
20
20
29
23
50
19
22
34
33
32
21
20
N.G.
N.G.
N.C.
30-70
2418
Device Type
(P in. WG)
VS/IS(25)b
VS/IS(25)
ISO)
VS(N.G.)
VS(N.G.)
VS/ISOO)
VS/ISOO)
VS/IS(27)
VS/ISO2)
VS/IS(25)
N.G.
N.G.
VS/ISU8)
VS(22)
N.G.
VS/IS(20)
N.G.
3IS(7)
3IS(8)
3IS(8)
N.G.
VS/IS(18)
VS/IS(9)
VS/IS(9)
N.G.
VSOO)
2019
P
pounds /dry
ton input
1.17
0.92
3.50
0.39
0.60
1.25
1.34
0.98
0.79
1.50
3.00e
2.80*
1.61e
0.20
0.91
0.64
0.67e
1.01
0.56
0.77
0.90
0.99
0.92
1.27
1.30
N.G.
1.2010.80
0.9U0.331
Calculated grains/dscf
C Concentration Equiv-
Concentration alent to 1.3 Ib/dry
(grains/dscf) ton - 1.3 x £ Source
0.009C
N.G.d
0.250
0.007
0.010
0.009C
0.010C
0.018°
0.015C
0.029°
0.046 (-12Z CO.)
0.042 (-12Z CO,)
0.015
0.010 (-12Z CO,)
N.G.
0.004
0.020
0.024
0.014
0.015
0.010
N.G.
0.008
0.036
0.009
0.004
0.01410.008
0.013
N/A
0.094
0.074
0.022
0.0126
0.0136
0.032s
0.032e
0.032s
0.015s
0.0156
0.012e
0.066
N/A
0.008
0.039e
0.031
0.033
0.026
0.015
N/A
0.011
0.037
0.009
N/A
0.02710.020
0. 02210. 0101
Rice, 1978
Rice, 1978
Rice, 1978
Rice, 1978
Rice, 1978
Rice, 1978
Rice, 1978
Rice, 1978
Rice, 1978
Rice, 1978
Story, 1976
Story, 1976
Cook, 1977
Jacobson, 1977
Van Natter, 1978
Lyttle, 1978
Ullrich, 1977
Petura, 1976
Petura, 1976
Petura, 1976
Spruiell, 1978
Langston Lab., 1977
Mullins, 1978
Mullins, 1978
Ecology Audits, 1977
Strandy, 1978
rMH: Multiple hearth incinerator.
VS/IS: Venturl scrubbex/l^ingenent scrubber.
.Grains/actual cubic foot.
TI.C.: Not given.
Co^>llance to 0.08 grains/dscf at 121 C02-
*TB: Fluidized bed incinerator.
TEL: Electric incinerator.
^Excludes E. Fltchburg, Erie and Morrisvllle.
-------
(0.69 Ib/ton) or 0.55 + 0.35 Kg/Mg (1.1 +. 0.69 Ib/ton) dry sludge
input. If the East Fitchburg incinerator and non-NSPS tests at
Erie #1 and #2 and Morrisville are deleted, the mean is 0.46 Kg/Mg
(0.91 Ib/ton) dry sludge input with a standard deviation of 0.17
Kg/Mg (0.33 Ib/ton) or 0.46 _+ 0.17 Kg/Mg (0.91 +_ 0.33 Ib/ton) dry
sludge input.
5.1.1 Scrubber Pressure Drop Versus Emissions
Where possible, information was collected on the type of
scrubber and the pressure drop used during the test as well as
the percent of solids present in the sludge. (The percent of
volatile solids was not readily available when the information was
compiled.) Pressure drops ranged from 3 to 32 in. WG, while sludge
solids ranged from 15 to 50 percent with the majority in the 20 to
35 percent range.
There does not appear to be a consistent relationship between
pressure drop in the scrubbers and emissions values. In Figure
5-1, the results are plotted as a function of scrubber pressure
drop and associated emissions on a mass basis. The East Fitchburg
result stands by itself and is unique in that a very low pressure
plate scrubber was used with apparently poor results. The cluster
of tests at about 8 in. WG are from the three incinerators in
Cincinatti and the two electric incinerators in Texas. With the
5-3
-------
East Fitchburg
3.0
R = -0.28 with East Fitchburg
R = 0.19 without East Fitchburg
01
oc
T3
3
.I
on
d
o
H
(-1
Q
OJ
4-1
m
,i
3
a
H
4-1
M
PM
cn
3
O
PM
2.0
NSPS
1.0
0
I
I
I
I
I
I
I
I
8 12 16 20 24 28 32 36 40
Scrubber Pressure Drop (Inches WG)
44 48
FIGURE 5-1
EMISSIONS VERSUS SCRUBBER PRESSURE DROP
5-4
-------
East Fitchburg incinerator included, the correlation coefficient*
is a poor -0.28 and, with that data point deleted, a poorer 0.19.
While the correlation between pressure drop and emission is poor,
the overall affect of the NSPS on control technology can readily be
seen by the average pressure drop of 20 in. WG. This is in contrast
to the facilities tested in 1974 when only one was found with a
venturi scrubber operating at 18 in. WG and the other facilities had
various plate scrubbers operating at 6 in. WG or less.
One set of test results indicates that, beyond a point, increas-
ing venturi scrubber pressure drops does not necessarily reduce par-
ticulate emissions on a mass basis. These test results, illustrated
in Figure 5-2, are from one multiple hearth incinerator operating on
nominal 30 percent sludge solids with pressure drops in a venturi/
impingement combination scrubber ranging from 22 to 35 in. WG
(Kroneberger, 1978). The sample correlation coefficient was -0.395,
a weak result at best. It should be pointed out, however, that the
correlation applies only to the pressure drop range of 22 to 35 in.
WG and would likely be much stronger if data covering pressure drops
of 0 to 36 in. WG were included in the calculation.
*The sample correlation coefficient is a useful statistical measure
of the relationship between two variables from sample data. Values
close to 1 or -1 indicate high positive or negative correlations,
respectively, while values near 0 indicate poor correlation.
5-5
-------
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Multiple Hearth
Venturi and Perforated Impingement Scrubbers
Nominal 30 Percent Solids
R = 0.40
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0.025
1.0
NSPS
n _0
0.018
0.018
0.011
0.008
0.015
1
1
1
1
1
1
1
1
1
20 22 24 26 28 30 32 34 36 38
Total Scrubber Pressure Drop (Inches WG)
Note: Values above data points are grains/dscf
Source: Kroneberger, 1978
40 42
FIGURE 5-2
EMISSIONS VERSUS SCRUBBER PRESSURE DROP
IN A MULTIPLE HEARTH INCINERATOR
5-6
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5.1.2 Emissions on a Volume Versus Mass Basis
As discussed in Section 3.3, the NSPS was first proposed as
a volume concentration standard equal to 0.071 grams/dscm (0.031
grains/dscf) based upon the analysis of emissions from three mul-
tiple hearth incinerators and two fluidized bed reactors. The test
results used at the time are summarized in Figure 5-3 (EPA, 1974).
Due to comments concerning the relative use of dilution air for
cooling the rabble arms in multiple hearth incinerators and the
difficulties involved in measuring and calculating corrections for
this factor, the standard was changed to particulate emissions per
weight of dry sludge burned. The equation used to make this con-
version was:
_. , , _ (Ib/ton dry sludge Facility A) x 0.031 grains/dscf
New standard v .,. "....T-*
grains/dscf Facility A
= °*481 x 0.031 =1.3 Ib/ton dry sludge
0.011 '
Critical to this calculation is the validity of the equiva-
lence of the emissions on a mass basis to the emission volume con-
centration. In Table 5-1, the ratio of volume concentration to the
emissions on a mass basis is calculated for each facility and then
normalized to 0.65 Kg/Mg (1.3 Ib/ton) dry sludge input. The average
from all tests shows an equivalent volume concentration of 0.062 _+_
0.046 grams/dscm (0.027 +_ 0.02 grams/dscf). If the results from
East Fitchburg, 0.216 grams/dscm (0.094 grains/dscf), the fluidized
5-7
-------
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PLANT, CONTROL EQUIPMENT
Note: Numbers in parentheses are grains/dscf
Source: EPA, 1974.
FIGURE 5-3
SUMMARY OF 1973 TEST RESULTS
USED FOR SETTING NSPS
5-8
-------
bed reactor at Tyrone, Pennsylvania, 0.151 grams/dscm (0.066 grains/
dscf), and the electric furnaces In Texas are deleted, multiple
hearth furnaces have an equivalent volume concentration of 0.050 ±
0.023 grams/dscm (0.022 + 0.010 gralns/dscf). If equivalent to
0.071 grams/dscm (0.031 grains/dscf), the resulting mass concentra-
tion would be 0.9 Rg/Mg (1.8 Ib/ton) dry sludge input.
Test data furnished to MITRE by an incinerator manufacturer
indicate a similar result (Kroneberger, 1978). Figure 5-4 is a plot
of grains/dry standard cubic foot versus pounds/dry ton of sludge at
a facility operating on 20 percent solids sludge with a venturi
scrubber at 13 to 17 in. WG. The correlation coefficient for these
data is 0.81. A nominal equivalence to 0.65 Rg/Mg (1.3 Ib/ton) dry
sludge input would occur at about 0.041 grams/dscm (0.018
grains/dscf). In Figure 5-5, another incinerator with higher sludge
solids and a venturi scrubber (unknown pressure drop) showed a
consistent relationship between volume and mass concentration
(R-0.95) but with an equivalence of 0.65 Rg/Mg (1.3 Ib/ton) dry
sludge input at 0.055 grams/dscm (0.024 grains/dscf).
Factors that may be at least partially responsible for the
difference in equivalent emission factors are the moisture content
and percent volatile matter in the input sludge. The amount of
combustion and combustion air required per dry pound of sludge
increases as the moisture content of the sludge increases and the
percent volatile matter decreases. The sludge used in the fluidized
5-9
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NSPS
Incinerator: Multiple Hearth
80 Percent Moisture
Scrubber 13-17 in. WG
R - 0.81
i
_L
I
0 .002 .004 .006 .008 .010 .012 .014
grains/dscf
Source: Kroneberger, 1978
,016 .018 .020
FIGURE 5-4
EMISSIONS ON A MASS VERSUS VOLUME BASIS:
LOW SLUDGE SOLIDS
5-10
-------
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*
09
1.0
Incinerator: Multiple Hearth
64.3 to 65.8 Percent Moisture
Venturl Scrubber
R - 0.95
NSPS
I
0.01
0.02
gralns/dscf
0.03
0.04
Source: Kroneberger, 1978
FIGURE 5-5
EMISSIONS ON A MASS VERSUS VOLUME BASIS:
HIGH SLUDGE SOLIDS
5-11
-------
bed incinerator of the background document was on the order of 20
percent solids with 80 percent volatile matter (Baer, 1978).* The
average solids content in Table 5-1 is 24 percent. Interestingly,
the Cincinnati and upper Blackstone results were about equivalent
to the results found by EPA in 1973 (e.g., 0.07 grams/dscm (0.03
grains/dscf) equivalent to 0.65 Kg/Mg (1.3 Ib/ton dry sludge input).
Each of the tests at these facilities involved input sludge with a
relatively high solids content of between 27 and 33 percent. Con-
versely, the incinerators at Merrimack, New Hampshire, operating on
16 percent sludge solids, have been tested several times and, even
with high scrubber pressure drops of 30 in. WG or more, have just
managed to reach the sludge standard despite low volume concentra-
tions of 0.020 and 0.023 grams/acm (0.009 and 0.010 grains/acf).**
The importance of sludge moisture content is strongly suggested
by the results in Figure 5-6, where a relatively high correlation
coefficient of 0.79 between sludge moisture content and increasing
mass concentrations was found (Kroneberger, 1978). Of particular
interest is the fact that this plant could meet the standard with
a three-stage impingement scrubber operating at the relatively low
pressure drop of 9 to 12 in. WG as long as the moisture content
*It should be noted that EPA records indicate that the tested
facility operated on 35 to 45 percent solids (Salotto, 1978).
The difference in these values has not been reconciled and it
is unknown which value was used to calculate sludge solids input.
**Unit 2 was considered not in compliance at 1.34 Ib/dry ton sludge
input.
5-12
-------
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Incinerator: Multiple Hearth
3 Stage Perforated Plate Impingement Scrubber (9 to 12 in. WG)
R - 0.79
NSPS
I
I
50 60 70 80
Percent Moisture in Sludge
90
100
Source: Kroneberger, 1978
FIGURE 5-6
EMISSIONS VERSUS SLUDGE MOISTURE CONTENT
IN A MULTIPLE HEARTH INCINERATOR
5-13
-------
remained UHH than 75 percent. The data in Table 5-1 only weakly
suggest this relationship (H-0.45) and, therefore, one can only con-
clude that facilities incinerating high moisture sludge may run the
risk of not meeting the N8P8 requirement and/or may require very
high energy scrubbers for particular removal.
5.1.J Particulate Emissions Ana lysis Summary
From the above analysis it appears that the current N8P8 it a
more stringent standard than originally acknowledged but, neverthe-
less, the majority of units can comply with this level* The stack
concentrations at complying units are very low and reflect removal
efficiencies of 98,5 to 99.5 percent at nominal input concentra-
tions of 40 to 75 Kg/Mg (80 to 150 Ib/ton) of dry sludge input. The
average scrubber pressure drop of 20 in* WG produced an average mass
emission rate of 0.46 Kg/Mg (0.91 Ib/ton) of dry sludge input and an
average volume emission rate of 0.050 graras/dscm (0.022 grains/dscf)
at incinerator! operating on a sludge with an average of 24 percent
solids.
The data are suggestive of a relationship between the percent
of sludge solids incinerated and mass emission concentration* with
higher solids content leading to lower emissions on a per dry ton
input basis. This implies a tradeoff between improving dewatering
operations or increasing capital and operating costs for emissions
control equipment (e.g., higher energy costs for Increased scrubber
pressure drops, extra scrubbing units).
5-14
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5.2 Opacity Measurements
While not indicated in Table 5-1 several tents included opacity
measurements. In only one case was an opacity level an high as 15
percent reported. The majority of reports were either 0 or 5 per-
cent. This appears consistent with the reported participate emia-
aions levels. The opacity standard was proposed as 10 percent with
exemptions in 1973 and then revised to 20 percent without exemptions*
except for startup and shutdown. No information received to date
contradicts the rationale used in setting the opacity level at 20
percent.
5.3 Mercury Levels
Information on mercury levels was collected from four incin-
erators* At Erie, Pennsylvania samples contained an estimated 600
grams/day in emissions exiting the scrubber of incinerator #1 and
450 grams/day exiting incinerator #2. In Appolo, Pennsylvania
the mercury concentration was 17 grams/day in the exit gas of the
scrubber. Samples of sludge input to the fluidiced bed reactor in
Tyrone, Pennsylvania indicated a 21 gram/day input rate. All these
values are well below the 3200 gram/day Federal emission level.
5-15
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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 sewage sludge incinera-
tion and to describe any new developments that have occurred since
the standard was proposed in 1973. The findings and recommendations
are presented below.
6.1 Findings
6.1.1 Incinerator Developments Since 1973
Approximately 240 SSIs are currently in operation. A total
of 19 MSSIs have been identified as candidates for the NSPS
and an additional 92 units were in the planning or construc-
tion stage as of mid-1977. This contrasts strongly with the
EPA mid-1973 estimate of 70 new MSSIs per year. The 1973
Oil Embargo and subsequent rise in energy prices and recent
emphasis on land disposal of sludge most likely had a strong
impact on the reduction of the projected number of units.
Most new units are projected to be of the multiple hearth
design.
The increase in fuel prices has led to increased efforts
toward autogeneous sludge incineration or, at a minimum,
recovery and use of waste heat. Improved dewatering tech-
niques from the increased use of chemicals, heat treatment
of sludge, and improved filtering equipment has helped
reduce the need for auxiliary fuel. Many new units are
now planned to utilize exhaust gases to produce steam to
run equipment or heat treat incoming sludge and should
operate as net energy exporters.
The electric incinerator, not operational in 1973, has
been tested for emissions in at least two locations. Un-
controlled emissions from these units are much lower than
those found in the fluidized bed or multiple hearth inci-
nerators. Collection efficiency requirements for these
units may, therefore, be lower than those needed for the
multiple hearth or fluidized bed incinerators. However,
it is noted that the indirect emissions due to electrical
power generation were not included in the emission rate
calculations for these units.
6-1
-------
6.1.2 Process Emissions and Control Technology
The current best demonstrated control technology is the
venturi scrubber in series with perforated impingement plate
scrubbers operating at about 20 in. WG pressure drop. Data
collected from tests indicate, however, that other factors
such as input sludge solids contents may be important para-
meters in selecting a control device. At least one facility
burning 30 percent sludge solids was tested and met the
standard using three-stage perforated plate impingement
scrubbers at pressure drops of 7 to 9 in. WG.
The equivalence of 0.071 grams/dscm (0.031 grains/dscf)
to 0.65 Kg/Mg (1.3 Ib/ton) dry sludge input used to set
the NSPS in 1974 appears to be incorrect with respect to
multiple hearth furnaces meeting the NSPS. The 0.65 Kg/Mg
(1.3 Ib/ton) dry sludge input standard has tested out to
be equivalent to 0.05 grams/dscm (0.022 grains/dscf). The
reasons for this are possibly related to differences in
combustion air requirements between multiple hearth inci-
nerators and the single fluidized bed incinerator used to
set the NSPS and the input sludge characteristics of the
single unit versus that found in the test data.
The NSPS has been complied with in most cases. The test
results were calculated to be 0.46 +_ 0.17 Kg/Mg (0.91 _+ 0.33
Ib/ton) dry sludge input and 0.032 _+ 0.018 grams/dscm (0.014
_+ 0.008 grains/dscf).
Particulate removal efficiences of 98.5 to 99.5 percent are
required and are being achieved based on uncontrolled emis-
sions of from 40 to 75 Kg/Mg (80 to 150 Ib/ton) dry sludge
input.
Units burning relatively wet sludge (e.g., 15 percent
solids) may have trouble meeting the NSPS with the best
demontrated control technology. This may be due to the
increased fuel and combustion air requirements per unit of
dry sludge burned necessary for evaporating the moisture.
The resulting particulate concentrations are lower and may
even tax the removal capacity of scrubbers operating at
relatively high pressure drops.
6-2
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6.1.3 Opacity Standard
Opacity measurements taken during NSPS tests ranged from 0 to 15
percent with the majority of measurements in the 0 to 10 percent
range.
6.1.4 Coincineration with Refuse
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 appropriate standard to
be used when jointly incinerating both types of waste.
6.1.5 State Standards
The NSPS is the more stringent standard in most states. The
Solid Waste Management Association of America (SWMAA) categorization
of solid wastes appears in several state incineration standards.
Sewage sludge is not categorized within the SWMAA definitions. Sev-
eral states have minimum stack temperature regulations of 1200° to
1600°F and/or incinerator design constraints*
6.2 Recommendations
6.2.1 Revision of the Standard
At this time there appears to be sufficient evidence to recom-
mend no revision of the values of the particulate standard or the
opacity standard. The rationale for this is based on the following
cons iderations:
6-3
-------
The standard is more stringent than originally indicated.
Removal efficiencies of 98.5 to 99.5 with volume concen-
trations of 0.058 to 0.062 grams/dscm (0.022 to 0.027
grains/dscf) are required to meet the standard.
There is no clear relationship between control technology
parameters and emission control. Factors such as percent
of sludge moisture and incinerator type may be as important
in achieving compliance as pressure drops in scrubbers.
The average emission level achieved was 0.45 _+_ 0.15 Kg/Mg
(0.9 +_ 0.3 Ib/ton) dry sludge input. The range of this
value and the relatively high pressure drops currently
employed indicate best demonstrated control technology
is meeting the standard with about a 25 percent margin
of error.
Very low opacity readings have been associated with most
NSPS particulate tests. However the rationale used to set
the 20 percent standard to include upsets, etc. is still
valid.
6.2.2 Definitions
Clarification of the applicable standard when jointly incinerat-
ing refuse and solid waste is desirable.
6.2.3 Research Needs
Given the poor correlation between emission values and scrubber
pressure drop, it would be desirable to ascertain those factors re-
sponsible for this situation. Evidence has been presented to indi-
cate that insufficient dewatering of sludge may cause problems in
achieving compliance. If this were shown to be so, for example,
then designs submitted to EPA as part of the grants program should
be evaluated on dewatering capability if incineration is to be used.
6-4
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7.0 REFERENCES
Balakrishnan, 8., Williamson, D., and Okey, P., 1970. State of the
Art Review on Sludge Incineration Practices. U.S. Department of
Interior, Federal Water Quality Administration. Document Number
17070DIV4/70:
Baer, G., 1978. Incinerator Operations Report 1/11/72, 1/12/72,
Jan/72. Northwest Bergen County Sewer Authority.
Cook, D., 1977. Letter to M. McDonagh. Subject: Morrisville
Performance Test. (Excerpt). . BSP Division, Envirotech
Corporation, Belmont, Calif.
Ecology Audits, 1977. Stack Emissions Survey Floyd Branch Wastewater
Treatment Plant for Shirco, Inc., Richardson, Texas (Excerpt).
Dallas, Tex.
Environmental Reporter, 1978. State Air Laws. The Bureau of Na-
tional Affairs, Inc., Washington, D.C.
Farmer, J. R., 1978. Chief, Standards Development Branch, EPA to
T. R. Banna, Department of Environmental Conservation, State of
Alaska. Letter. Subject: NSPS for Sewage Sludge Incinerators.
Farrell, J., H. Wall, and B. Kerdolff, 1978. Air Pollution From
Sewage Sludge Incinerators: A Progress Report. Presented at the
6th U.S.-Japan Conference, Cincinnati, Ohio, October 30, 1978.
Federal Register, 1977. Standards of Performance for New Stationary
Sources, Amendment to Subpart 0: Sewage Sludge Incinerators. 42
FR 58520-5821, November 10.
Federal Register, 1977a. Municipal Sludge Management, Environmental
Factors; Technical Bulletin. 42 FR 57420.
Furr, A., et al., 1976. Multielement and Chlorohydrocarbon Analysis
of Municipal Sewage Sludge of American Cities. Environmental
Science and Technology. Vol. 10, pg. 683.
Gordian Associates, Inc., 1978. Assessment of the Use of Refuse-
Derived Fuels in Municipal Wastewater Sludge Incinerators. Pre-
pared for U.S. Environmental Protection Agency, Office of Solid
Wastes.
Jacobson, 1977. Acceptance Test Report, Solids Handling System,
Tyrone Regional Water Pollution Control Center (Excerpt). Copeland
Systems, Inc.
7-1
-------
Kalinski, A., et al., 1975. Study of Sludge Disposal Alternatives
for the New York-New Jersey Metropolitan Area. Presented at the
48th Annual Conference of the Water Pollution Control Federation,
Miami Beach, Fla.
Kroneberger, G., 1978. Letter to R. Helfand, MITRE Corporation.
Subject: Correlation of Data From Sewage Sludge Incinerators.
BSP Division, Envirotech Corporation.
Kroneberger, G., 1978a. Personal Communication. BSP Division, Envi
rotech Corporation.
Langston Laboratories, 1977. Stationary Source Particulate Emission
Analysis, Johnson County Unified Sewer District, Mission Main and
Turkey Creek Plants, Unit 2, Mission, Kansas (Excerpt). Leawood,
Kans.
Liao, P. B., and M. J. Pilat, 1972. Air Pollutant Emissions from
Fluidized Bid Sewage Sludge Incinerators. Water and Sewage Works.
119(2):68-74.
Lyttle, T., 1978. Letter to K. Barrett, MITRE Corporation. Sub-
ject: Maryville, Tennessee Sewage Sludge Test Results. U.S.
Environmental Protection Agency, Region IV. Atlanta, Ga.
Mullins Engineering Testing Company, Inc., 1978. Source Emissions
Survey, North Texas Municipal Water District, Rowlett Creek Plant,
Piano, Texas. Dallas, Tex.
Petura, R. C., 1976. Operating Characteristics and Emission Perfor-
mance of Multiple Hearth Furnaces With Sewer Sludge. In Proceed-
ings of 1976 National Waste Processing Conference, pp. 313-327.
Rice, R. , 1978. Personal Communication. U.S. Environmental Protec-
tion Agency, Region I. Boston, Mass.
Salotto, V., 1978. Personal Communication. U.S. Environmental Pro-
tection Agency. Cincinnati, Ohio.
Schmidt, D., 1978. Personal Communication. Hampton Roads Sanitary
District. Hampton Roads, Va.
Shirco, Inc., 1978. Source Emissions Survey North Texas Municipal
Water District, Rowlett Creek Plant, Piano, Texas. Performed by
Mullins Environmental Testing Co., Inc. Dallas, Tex.
7-2
-------
Spruiell, S., 1978. Personal Communication. Subject: Lawton,
Oklahoma Source Test. U.S. Environmental Protection Agency, Region
VI. Dallas, Tex.
Story, J., 1976. Letter to D. Cook, Envirotech Corporation. Sub-
ject: Erie, Pennsylvania Sludge Incinerator Tests. The Mogul
Corporation, Chagrin Falls, Ohio.
Strandy, R., 1978. Personal Communication with K. Barrett, MITRE
Corporation. U.S. Environmental Protection Agency, Region X.
Seattle, Wash.
Sussman, D. B., and H. W. Girshman, 1978. Thermal Methods for the
Codisposal of Sludges and Municipal Residues. Presented at the
Fifth National Conference on Acceptable Sludge Disposal Techniques,
Jan. 31 - Feb. 2.
Ullrich, D., 1977. Letter to R. Haller, MW, Incorporated,
Indianapolis, Indiana. Subject: Granite City, Illinois Sludge
Incinerator Stack Test (Excerpt). Air Enforcement Branch, U.S.
Environmental Protection Agency, Region V. Chicago, 111.
U.S. Environmental Protection Agency, 1973. Background Information
for Proposed New Source Performance Standards: Asphalt Concrete
Plants, Petroleum Refineries, Storage Vessels, Secondary Lead
Smelters and Refineries, Brass or Bronze Ingot Production Plants,
Iron and Steel Plants, Sewage Treatment Plants. Vol. I.
APTD-1352a.
U.S. Environmental Protection Agency, 1974. Background Information
for New Source Performance Standards: Asphalt Concrete Plants»
Petroleum Refineries, Storage Vessels, Secondary Lead Smelters, and
Refineries, Brass or Bronze Ingot Production Plants, Iron and Steel
Plants, Sewage Treatment Plants. Vol. III. APTD-1352c.
U.S. Environmental Protection Agency, 1974a. Process Design Manual
for Sludge Treatment and Disposal. EPA-625/1-74-006. Office of
Technology Transfer, Cincinnati, Ohio.
U.S. Environmental Protection Agency, 1974b. Background Information
on National Emission Standards for Hazardous Pollutants - Proposed
Amendments for Asbestos and Mercury. EPA 450/2-74-0099.
U.S. Environmental Protection Agency, 1975. Air Pollution Aspects of
Sludge Incineration. EPA-625/4-75-009.
7-3
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U.S. Environmental Protection Agency, 1975a. Determination of In-
cinerator Operator Conditions for the Safe Disposal of sticides.
EPA 600/2-75-041.
U.S. Environmental Protection Agency, 1977. Letter from J. Rhett,
Deputy Assistant Administrator for Water Programs Operations, to
Honorable John D. Dingall, U.S. House of Representatives. Subject:
Energy Inventory of Sewage Sludge Incinerators. Washington, D.C.
U.S. Environmental Protection Agency, 1977a. Compilation of Air
Pollution Emission Factors 2nd Ed., AP-42. Office of Air Quality
Planning and Standards, Research Triangle Park, N.C.
U.S. Environmental Protection Agency, 1978. Research Outlook, 1978.
EPA 600/9-78-001. Office of Research and Development, Washington,
D.C.
U.S. Environmental Protection Agency, 1978a. 1975 National Emissions
Report. National Emissions Data System of the Aerometric and
Emissions Reporting System. EPA 450/2-78-020. Office of Air
Quality Planning and Standards, Research Triangle Park, N.C.
Van Natter, C., 1978. Personal Communication. MITRE Corporation.
Subject: Hopewell, Virginia Sludge Incinerator Test. Regional
Wastewater Treatment Plant. Hopewell, Va.
Whitmore, F., 1975. Destruction of Polychlorinated Biphenyls in
Sewage Sludge During Incineration. Versar, Inc., Springfield,
Va.
Whitmore, F. and R. Durfee, 1974. Lead and Mercury Balance at the
Palo Alto Incinerator. Versar, Inc., Springfield, Va.
Whitmore, F. and R. Durfee, 1975. A Study of Pesticide Disposal
in a Sewage Sludge Incinerator. Versar, Inc., Springfield, Va.
7-4
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing}
\. REPORT NO.
EPA-450/3-79-010
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
A Review of Standards of Performance for New
Stationary Sources - Sewage Sludge Incinerators
5. REPORT DATE
March 1979
8. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Richard M. Helfand
8. PERFORMING ORGANIZATION REPORT NO.
MTR-7910
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Metrek Division of the MITRE Corporation
1820 Oolley Madison Boulevard
Me Lean, VA 22102
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-02-2526
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
DAA for Air Quality Planning and Standards
Office of Air, Noise, and Radiation
U. S. Environmental Protection Agency
Research Triangle Park, NC 27711
14. SPONSORING AGENCY CODE
EPA 200/04
15. SUPPLEMENTARY MOTES
16. ABSTRACT
This report reviews the current Standards of Performance for New Stationary
Sources: Subpart 0 - Sewage Sludge Incinerators. It includes a summary of
the current standards, the status of applicable control technology, and the
ability of sewage sludge incinerators to meet current standards. Compliance
test results are analyzed and a recommendation made to retain the current
standard. Information used in this report is based upon data available as
of November 1978.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
COSATI Field/Group
13B
8. DISTRIBUTION STATEMENT
Release Unlimited
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
67
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (R«v. 477) PREVIOUS EDITION is OBSOLETE
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