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OAR Box 1787 

Prepped by Ollie Stewart 

Document Number: 

26) II-B-11 

Docket Number: 

A-90-37 

Printed 11/4/2008 10:22:19 AM Sheet 26 of 147 
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A-10-I") 

JL-&-H 

15S2. 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

Office of Air Quality Planning and Standards 

Research Triangle Park, North Carolina 27711 

2 S JUN 1337 

MEMORANDUM 

SUBJECT: • Operational Guidance on Control Technology for New and 

Modified Municipal Waste Combustors (MWCs) 

FROM: Gerald A. Emison, Directpj^^^^^s- ^ \\"7-,'.,...A*- L > -"-' ' 

PTanninc 

*),\A:rt DOCKET..-

Office of Air Quality Planning and standards (MD-100, '' o\o 

I. jw25itj..:; ID 

TO: Air Management Division Directors 

•Regions I, III, Y and IX 

Air and Waste Management Division Director ^-

Region II 

Air, Pesticides, and Toxics Management Division Directors 

Regions IY and VI 

Air and Toxics Division Directors 

Regions YII, VIII and X 

As you know, numerous questions regarding the selection of appropriate 

pollution control requirements for MWCs have arisen during recent years 

in major source permitting proceedings under the prevention of significant 

deterioration (PSD) provisions of Part C of the Clean Air Act and the 

nonattainment new source review (NSR)- provisions of Part D of the Act. 

Accordingly, the attached operational guidance is being issued to promote 

consistency in making best available control technology (BACT) determinations 

under PSD and lowest achievable emission .rate (LAER).determinations under 

nonattainment NSR, and to reduce delay and confusion in the.permitting 

process. This guidance requires reviewing authorities, in considering the 

range of potential control options during the BACT determination process 

for MWCs, to consider a dry scrubber and a fabric filter or electrostatic 

precipitator as BACT for sulfur dioxide (SO2) and particulate matter (PM), 

and combustion controls as BACT for carbon monoxide (CO). 

The Administrator remanded to Region IX on June 22, 1987, their previous 

concurrence on a PSD permit for the H-Power MWC to be constructed in Honolulu,-

Hawaii. Petitioners had argued that, (a) BACT for this facility did not 

adequately justify the failure to require the use of an acid gas scrubber, 

and (b) the permitting authority did not evaluate the effectiveness of acid 

gas scrubbers in reducing emissions of unregulated pollutants, as required 
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by the June 1986 North County Resource Recovery Associates PSD Appeal 

decision (or North County remand). In remanding the H-Power permit application to Region IX for further proceedings, the Administrator made it 

clear that the. Agency considers acid gas scrubbers to be an available 

technology for excess air MWCs that fire refuse-derived fuel (RDF) such as 

the H-power facility. The attached operational guidance states that this 

type of post-combustion control is one component of available technology 

for modular, starved air MWCs and massburn, excess air MWCs, in addition to 

RDF-fired, excess air MWCs. 

As stated above, the operational guidance includes a second component 

of available technology, which is combustion control for the criteria 

pollutant CO. Since the effectiveness of the two components of available 

technology in controlling unregulated pollutants is an important consideration 

in individual BACT determinations (per the North County remand), the 

attached guidance states that (a) acid gas scrubbers followed by fabric 

filters or electrostatic precipitators are effective in controlling 

potentially toxic organic and metal pollutants, as well as acid gases 

other than sulfur dioxide, and (b) combustion controls are effective in 

controlling potentially toxic organic pollutants. 

The technical basis for the operational guidance is documented in 

five reports which are a part of the Agency's comprehensive study of MWC. 

These volumes are listed in the References section of the guidance. You 

will note that the guidance indicates "specified values" should be selected 

on a site specific basis for several design and operating parameters pf 

the facility and for emissions of criteria pollutants. A thorough discussion 

of the factors to be considered in choosing the "selected values" is 

included in the five reports from the comprehensive MWC study. 

As noted under Section Y, this guidance should be. transmitted to all 

State and local agencies to which PSD permitting authority has been delegated 

under 40 CFR Section 52.21(u). The transmittal letter should specify that 

the delegation agreement is amended to include this guidance. States which 

have received SIP approval of a PSD program under 40 CFR Section 51.166 

(formerly Section 51.24) should also be informed of this guidance and of 

EPA's expectation that it be followed. 

Attachment 

cc: James DeMocker (ANR-443) 

Gregory Foote (LE-132A) 

Steve Greene (WH-565) 

-Joseph E. Lees (ANR-443) 

J. Craig Potter (ANR-443) 

John C. Ulfelder (A-101) 

Marcia Williams (WH-562) 
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6/26/87 

OPERATIONAL GUIDANCE ON CONTROL 

TECHNOLOGY FOR NEW AND MODIFIED 

MUNICIPAL WASTE COMBUSTORS 

I. The Need for Guidance. 

The combustion of municipal waste represents an increasingly important 

element of the solid waste disposal problem in the U.S. However, the 

operation of municipal waste combustors (MWCs) releases potentially harmful 

pollutants to the air. Human exposure can occur directly or indirectly, 

and there is also concern that the environment could be vulnerable to 

long-term accumulation of emitted pollutants. EPA is addressing these 

issues in a comprehensive, integrated Municipal Waste Combustion Study and 

with this operational guidance. 

Numerous questions regarding the selection of appropriate pollution 

control requirements have arisen during recent years in major source 

permitting proceedings under the prevention of significant deterioration 

(PSD) provisions of Part C of the Act and the nonattainment new source 

review (NSR) provisions of Part D of the Act. Uncertainty over these 

questions has led to conflict over minimum legal requirements and consequent 

delay in the permitting and construction of MWCs. Hence, there is a need 

for guidance to resolve controversies which may arise as to facilities 

seeking permits. Accordingly, EPA is issuing this operational guidance 

for use in making best available control technology (BACT) determinations 

under PSD and lowest achievable emission rate (LAER) determinations under 

nonattainment NSR. EPA believes that this guidance will promote consistency 

in control requirements, and reduce delay and confusion in the permitting 
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process. At the same time i t wil l allow permitting authorities to give 

appropriate consideration to local factors in making case-by-case BACT 

determinations as required under law. 

I I . Administrative History . 

Section 169(3) of the Act provides that BACT determinations in PSD 

permits must be "based on the maximum degree of reduction of each pollutant 

subject to regulation under thi s [Act] . . . which the permitting authority , 

on a case-by-case basis, taking into account energy, environmental, and 

economic impacts and other costs, determines is achievable." EPA's . 

regulations track thi s language. See 40 C.F.R. 52.21(b)(12), 40 C.F.R. 

51.166(b)(12). In addition, in two administrative appeals involving 

resource recovery facilities , EPA has further refined the analysis which 

permitting authorities must conduct in making BACT determinations. 

In North County Resource Recovery Associates, PSD Appeal No. 85-2 

(June 3, 1986), the Administrator issued a Remand Order which held that, 

in making BACT determinations for a regulated air pollutant , the permitting 

authority must consider the effec t of that decision on emissions of pollutants 

not regulated under the Clean Air Act. North County provided that the 

fina l BACT decision should address these environmental impacts, and that 

the permitting authority may ultimately choose more stringent emissions 

limitation s for the regulated pollutant than i t would otherwise have chosen 

i f i t would have the collatera l benefit of restrictin g emissions of the 

unregulated pollutant. In the North,County case, the permitting authority 

had required the use of a dry scrubber and fabric filte r as BACT for sulfur 

dioxide, but had faile d to consider the effec t of that decision on emissions 
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of certain unregulated pollutants -- dioxins and furans, heavy metals, and 

acid gases -- on the grounds that it lacked authority to do so. Various 

persons petitioned the Administrator under 40 C.F.R. Part 124. In response 

to the Administrator's subsequent remand order, the permitting authority 

analyzed the effect of various control options on these three classes of 

pollutants, and found that no other controls on regulated pollutants would 

be more effective in reducing emissions of the unregulated pollutants. The 

Administrator then ruled that the permitting authority had satisfied the 

requirements of the remand order, and denied the petitions. See North 

County Resource Recovery Associates, PSD Appeal No. 85-2, Order Denying 

Review (September 4, 1986). 

The Administrator ruled in Honolulu Resource Recovery Facility 

("H-Power"), PSD Appeal No. 86-6, Remand Order (June 22, 1987), that a PSD 

permitting authority has the burden of demonstrating that adverse economic 

impacts justify the failure to require as BACT the most effective control 

technology which is available. He also found that acid gas scrubbers are 

an available control technology for sulfur, dioxide (SO2). The H-Power 

decision also provided that the economic impacts must be- specific to the 

source in question and substantial. Thus, because the Administrator 

agreed with EPA Region IX that Hawaii had not adequately demonstrated the 

basis for its conclusion that economic factors justified the absence of 

flue gas treatment as BACT for SO2, he remanded the matter for further 

proceedings. 
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EPA today also draws upon the technical data referenced below, and 

its experience in issuing, reviewing, and enforcing PSD permits for MWCs. 

Recent emission test data have demonstrated that particulate matter (PM), 

SO2, and other air pollutants (including organics, heavy metals, and acid 

gases) can be controlled effectively by acid gas scrubbing devices (dry 

scrubbers) equipped with efficient particulate collectors. Over 20 MWC 

facilities in Europe are known to be operating with dry scrubbers and 

particulate collectors, and at least 37 such facilities are known to exist 

in Japan. In the United States, three facilities currrently are in operation 

and at least 15 have been permitted to construct with dry scrubbing and 

particulate control devices as the specified technology. Thirteen of these 

facilities are expected to be operating by December 1988. 

Based on this information, it is clear that a dry scrubber followed 

by either a fabric filter or electrostatic precipitator are "available" 

technologies for effective control of the SO2 and PM emitted by MWCs, and 

that these technologies also are effective in controlling emissions of 

potentially toxic organic and heavy metal pollutants, and acid gases 

other than SO2. In addition, the data show that these technologies are 

reliable and reasonably affordable. Similarly, combustion controls are 

an available technology for the control of carbon monoxide (CO) emitted 

by MWCs, and are effective in controlling that criteria pollutant and 

potentially toxic organic pollutants. EPA's information indicates that 

this technology also is reliable.and reasonably affordable. 
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III . BACT Guidance for SO2, PM,. and CO. 

Accordingly, in considering the range of potential control options 

during the SACT determination process for MWCs, the reviewing authority 

must consider a dry scrubber and a fabric filte r or electrostatic precipitator 

as BACT for SO2 and PM, and combustion controls as BACT for CO. In order 

to justif y a BACT determination calling for a lesser degree of emissions 

control than can be achieved using these technologies, the permitting 

authority must demonstrate, based on information contained in the permit 

file , that significant technical defects, or substantial adverse economic, 

energy, or environmental impacts or other costs would arise that are 

specific to the MWC in question. Permitting authorities remain free to 

make case-by-case judgments in accordance with today's guidance. However, 

based on the above-referenced information regarding legal requirements 

and the availability, effectiveness, and cost of these technologies, EPA 

expects that proper application of this guidance wil l result in few, i f 

any, BACT determinations entailing application of pollution control 

technologies less effective than.those called for herein. 

Today's guidance is general; i t is limited to describing types of 

post-combustion control equipment and to establishing general criteria 

for combustor design, combustor operating practices, emission monitoring, 

and operator training. I t does not set specific emission limits . Detailed 

information regarding the maximum degree of emissions control achievable 

with these technologies is available in the referenced technical documents, 

the BACT/LAER Clearinghouse, or from EPA. Such information should be 

used by applicants and permitting authorities setting specific emissions 
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limits for PSD permits. In addition, today's guidance only addresses 

control technologies currently in widespread use for MWCs, and establishes 

minimum criteria for BACT determinations. Permitting authorities are not 

relieved of their responsibility to consider, on a case-by-case basis, 

whatever available technologies may be anticipated to provide a greater 

degree of control than those addressed today. Similarly, because control 

technologies and the other factors in forming BACT determinations are 

constantly evolving, the technology providing the greatest degree of 

emissions control taking economic, energy, and environmental impacts into 

account may likewise change over time. As one example, flue gas treatment 

technology for the criteria pollutant nitrogen oxides (N0X) is in operation 

at one MWC in the U.S., and this technology should be considered by permitting 

authorities in making BACT determinations. In addition, emerging technologies 

in flue gas cleaning may develop which can attain the level of multipollutant 

control currently demonstrated by dry scrubbing/particulate matter controls, 

and technologies such as these .should be considered in future BACT determinations. 

Permitting authorities and applicants must keep abreast of new developments. 

Of course, EPA will assist in this endeavor. 

IV. LAER Guidance for Nonattainment Areas. 

The technologies discussed herein for control of SO2 PM, CO, and N0X 

have all been successfully implemented, and thus have been "achieved in 

practice" by MWCs within the meaning of section 171(3) of the Act. 

Hence, in nonattainment areas where NSR requirements apply and major new 

sources and modifications must apply LAER, no less effective pollution 

control technologies may be imposed as LAER. 
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V. Implementation. 

Today's guidance applies to all ongoing PSD and NSR proceedings, as 

well as to all new permit applications. In consideration of the needs 

for program stability and equity to sources which have in good faith 

relied on pre-existing permitting guidelines, this guidance does not 

apply to PSD and NSR permit proceedings for which, as of June 26, 1987, 

final permits have already been issued and, with respect to PSD permits 

issued by EPA, agency review procedures under 40 C.F.R. Part 124 have been 

exhausted. 

This operational guidance applies to PSD permits issued by EPA directly 

through its Regional .offices and indirectly through State and local 

agencies pursuant to delegation agreements made under 40 C.F.R. 52.21(u). 

Such agencies will be notified by letter of this guidance. It will 

constitute an amendment to the pre-existing delegation agreements. EPA 

Regional offices will review all draft permits for MWCs issued by delegate 

agencies during the public comment period to insure proper application. 

Further program evaluation will take place under the National Air Audit 

System (NAAS). If delegate agencies should fail to adhere to this guidance, 

EPA staff may initiate administrative appeal proceedings under 40 C.F.R. 

Part 124 in appropriate cases. Such action would be appropriate where, for 

example, failure to follow the guidance results in a finding of fact or 

conclusion of law which is clearly erroneous, or involves an exercise of 

discretion or an important policy consideration which the Administrator 

should review. See 40 C.F.R. 124.19(a). Action would also be appropriate 

where failure to follow the guidance resulted in an inability to determine, 
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based on the record, whether a clear error occurred. If necessary, EPA 

may also revoke the delegation of PSD authority to the State or local 

agency. 

With respect to State PSD permits issued pursuant to a State implementation 

plan (SIP) program approved by EPA under 40 C.F.R. 51.166 (formerly 51.24), 

and State NSR programs approved under Part D of the Act and 40 C.F.R. 

51.165 (formerly 51.18(j)), EPA expects States to follow today's guidance 

in generally the same fashion as delegate agencies. EPA will use the 

guidance as a reference point in its oversight of State MWC permit actions. 

As with delegated permits EPA will participate in permit proceedings and 

conduct NAAS evaluations. If agencies processing NSR permits or PSD 

permits under approved State programs should fail to adhere to this 

guidance, EPA may initiate administrative and/or judicial action under 

sections 113 and/or 167 of the Act in appropriate cases. Such action 

would be appropriate where, for example, failure to follow the guidance 

results in a finding of fact or conclusion of law which is clearly erroneous, 

or in an inability to determine whether a clear error occurred. If 

necessary, EPA may also call for SIP revisions under section 110(a)(2)(H). 

Insofar as today's guidance addresses minimum legal requirements for 

BACT determinations, it simply implements existing regulations and policy, 

including Agency actions already "ade by the Administrator in the North 

County and H-Power cases. To the extent the guidance addresses the technical 

issues of availability, effectiveness, and cost of control technologies for 

MWCs, it expresses EPA's view regarding the proper usage, in permit proceedings 

under existing EPA regulations and SIP programs, of the factual data contained 
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in the five documents referenced below. Those documents present information 

on the alternative controls available for MWCs, the performance capabilities 

and costs of those controls, and the methods for monitoring and measuring 

emissions from MWCs. Factors to be considered in choosing the "specified 

values" to be included in permits, as noted in the guidance, such as maximum 

concentration of CO in emissions and minimum value of furnace temperature, 

are contained in these references. Thus, the guidance does not constitute 

rulemaking within the meaning of section 307(d) of the Act or under the 

Administrative Procedure Act. Accordingly, it is not necessary to implement 

this guidance, as to EPA permits issued by Regional offices or State and 

local agencies, through changes in the PSD regulations at 40 C.F.R. 52.21. 

Likewise, regarding approved State PSD programs, it is not necessary to 

revise 40 C.F.R. 51.166 and require corresponding SIP revisions. 

VI. Technical Guidance. 

Today's operational guidance applies to three types of MWCs: 

massburn, excess air MWCs; excess air MWCs that fire refuse-derived fuel; 

and modular, starved air MWCs. It applies to those MWCs that operate with 

energy recovery and those that operate without energy recovery. It applies 

to both major new and major modified facilities.of these types. The guidance 

requires that values for emission limits and operating parameters be specified 

in MWC permitting decisions. 

One component of control technology for MWCs is the application of the 

appropriate post-combustion control equipment. The EPA has identified 

this equipment as a dry scrubber with fabric filter or with electrostatic 
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precipitator. The concentration of particulate emissions in the exhaust 

gases from the post-combustion control equipment shall not exceed a 

specified maximum value; and the SO2 emissions in the exhaust gases 

shall not exceed a specified maximum concentration value or the percent 

reduction in SO2 emissions across the post-combustion control equipment 

shall not be less than a specified value. Performance of the dry scrubber 

and fabric filter or electrostatic precipitator in controlling acid 

gases, potentially toxic metals, and potentially toxic organic pollutants 

is affected sigificantly by the reduction in flue gas temperature which 

occurs in the dry scrubber. The control system shall be designed and 

operated such that the flue gas temperature at the outlet from the dry 

scrubber does not exceed a specified value. 

; A second component of control technology for MWCs is proper design 

and operation of the combustion syjstem, which controls CO and potentially 

toxic organic pollutants. Minimum concentrations of CO in emissions from 

MWCs are associated with the implementation of several good combustion 

practices. These practices are also related to the effective destruction 

of potential emissions of toxic organic pollutants, including dioxins and 

furans. Concentrations of CO in furnace exhaust gases shall not exceed a 

specified maximum value, and CO and O2 concentrations in the exhaust gases 

shall be monitored continuously. In addition, furnace operating temperatures 

shall be no lower than a specified minimum value, and a procedure for continuous 

monitoring shall be established to ensure that the specified temperature is 

maintained. 
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The capabilities to control flow rates and distributions of underfire 

(primary) and overfire (secondary) air, to monitor, continuously CO 

concentration and furnace temperature, to maintain thermal load within a 

specified range, and to control the process to maintain CO and temperature 

of the furnace at appropriate levels, are all important to good combustion. 

Detailed information regarding the numerical values to be assigned to the 

emission levels and equipment design and operating parameters associated 

with good combustion are provided in the documents cited under References. 

References: 

Municipal Waste Combustion Study: Emission Data Base for Municipal 

Waste Combustors. 

EPA/530-SW-87-021B 

Municipal Waste Combustion Study: Combustion Control of Organic Emissions. 

EPA/530-SW-87-021C 

Municipal Waste Combustion Study: Flue Gas Cleaning Technology. 

EPA/530-SW-87-021D 

Municipal Waste Combustion Study: Cost of Flue Gas Cleaning Technologies. 

EPA/530-SW-87-021E 

Municipal Waste Combustion Study: Sampling and Analysis. 

EPA/530-SW-87-021F