Standards of Performance for New Stationary Sources and Emission Guidelines for Existing Sources: Commercial and Industrial Solid Waste Incineration Units

Federal RegisterJun 4, 2010

Ask Donna

What actually matters in this document.

Text

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 60

[EPA-HQ-OAR-2003-0119; FRL-9148-4]

RIN 2060-AO12

Standards of Performance for New Stationary Sources and Emission Guidelines for Existing Sources: Commercial and Industrial Solid Waste Incineration Units

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Proposed rule.

SUMMARY:

On December 1, 2000, EPA adopted new source performance standards and emission guidelines for commercial and industrial solid waste incineration units established under Sections 111 and 129 of the Clean Air Act. In 2001, EPA granted a petition for reconsideration regarding the definitions of “commercial and industrial waste” and “commercial and industrial solid waste incineration unit.” In 2001, the United States Court of Appeals for the District of Columbia Circuit granted EPA's voluntary remand, without vacatur, of the 2000 rule. In 2005, EPA proposed and finalized the commercial and industrial solid waste incineration definition rule which revised the definition of “solid waste,” “commercial and industrial waste,” and “commercial and industrial waste incineration unit.” In 2007, the United States Court of Appeals for the District of Columbia Circuit vacated and remanded the 2005 commercial and industrial solid waste incineration definition rule.

This action provides EPA's response to the 2001 voluntary remand of the 2000 rule and the vacatur and remand of the commercial and industrial solid waste incineration definition rule in 2007. In addition, this action includes the five-year technology review of the new source performance standards and emission guidelines required under Section 129. This action also proposes other amendments that EPA believes are necessary to adequately address air emissions from commercial and industrial solid waste incineration units.

DATES:

Comments.

Comments must be received on or before July 19, 2010. Under the Paperwork Reduction Act, comments on the information collection provisions must be received by the Office of Management and Budget (OMB) on or before July 6, 2010.

Public Hearing.

We will hold a public hearing concerning this proposed rule and the interrelated proposed Boiler and RCRA rules, discussed in this proposal and published in the proposed rules section of today's

Federal Register

, on June 21, 2010. Persons requesting to speak at a public hearing must contact EPA by June 14, 2010.

ADDRESSES:

Submit your comments, identified by Docket ID No. EPA-HQ-OAR-2003-0119, by one of the following methods:

http://www.regulations.gov:

Follow the on-line instructions for submitting comments.

E-mail:

Send your comments via electronic mail to

a-and-r-Docket@epa.gov,

Attention Docket ID No. EPA-HQ-OAR-2003-0119.

Facsimile:

Fax your comments to (202) 566-9744, Attention Docket ID No. EPA-HQ-OAR-2003-0119.

Mail:

Send your comments to: EPA Docket Center (EPA/DC), Environmental Protection Agency, Mailcode 6102T, 1200 Pennsylvania Ave., NW., Washington, DC 20460, Attention Docket ID No. EPA-HQ-OAR-2003-0119. Please include a total of two copies. We request that a separate copy also be sent to the contact person identified below (

see

FOR FURTHER INFORMATION CONTACT

Hand Delivery:

Deliver your comments to: EPA Docket Center (EPA/DC), EPA West Building, Room 3334, 1301 Constitution Ave., NW., Washington, DC 20460, Attention Docket ID No. EPA-HQ-OAR-2003-0119. Such deliveries are accepted only during the normal hours of operation (8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays), and special arrangements should be made for deliveries of boxed information.

Instructions:

Direct your comments to Docket ID No. EPA-HQ-OAR-2003-0119. The EPA's policy is that all comments received will be included in the public docket and may be made available on-line at

http://

www.regulations.gov,

including any personal information provided, unless the comment includes information claimed to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Do not submit information that you consider to be CBI or otherwise protected through

http://

www.regulations.gov

or e-mail. The

http://

www.regulations.gov

Web site is an “anonymous access” system, which means EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an e-mail comment directly to EPA without going through

http://

www.regulations.gov,

your e-mail address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the Internet. If you submit an electronic comment, EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD-ROM you submit. If EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, EPA may not be able to consider your comment. Electronic files should avoid the use of special characters, any form of encryption and be free of any defects or viruses.

Public Hearing:

We will hold a public hearing concerning the proposed rule on June 21, 2010. Persons interested in presenting oral testimony at the hearing should contact Ms. Joan Rogers, Natural Resources and Commerce Group, at (919) 541-4487 by June 14, 2010. The public hearing will be held in the Washington, DC area at a location and time that will be posted at the following Web site:

http://www.epa.gov/airquality/combustion.

Please refer to this Web site to confirm the date of the public hearing as well. If no one requests to speak at the public hearing by June 14, 2010 then the public hearing will be cancelled and a notification of cancellation posted on the following Web site:

http://www.epa.gov/airquality/combustion.

Docket:

EPA has established a docket for this action under Docket ID No. EPA-HQ-OAR-2003-0119. All documents in the docket are listed in the

http://

www.regulations.gov

index. Although listed in the index, some information is not publicly available,

e.g.,

CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, will be publicly available only in hard copy form. Publicly available docket materials are available either electronically at

http://

www.regulations.gov

or in hard copy at the EPA Docket Center EPA/DC, EPA West, Room 3334, 1301 Constitution Ave., NW., Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202) 566-1744 and the telephone number for the EPA Docket Center is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT:

Ms. Charlene Spells, Natural Resource and Commerce Group, Sector Policies and Programs Division (E143-03), Environmental Protection Agency, Research Triangle Park, North Carolina

27711; telephone number: (919) 541-5255; fax number: (919) 541-3470; e-mail address:

spells.charlene@epa.gov

or Ms. Toni Jones, Natural Resource and Commerce Group, Sector Policies and Programs Division (E143-03), Environmental Protection Agency, Research Triangle Park, North Carolina 27711; telephone number: (919) 541-0316; fax number: (919) 541-3470; e-mail address:

jones.toni@epa.gov.

SUPPLEMENTARY INFORMATION:

Organization of This Document.

The following outline is provided to aid in locating information in this preamble.

I. General Information

A. Does the proposed action apply to me?

B. What should I consider as I prepare my comments?

II. Background

A. What is the statutory authority for these proposed rules?

B. What are the primary sources of emissions and what are the emissions and current controls?

C. What is the relationship between this proposed rule and other combustion rules?

III. Summary of the Proposed Rule

A. Litigation and Proposed Remand Response

B. Proposed CAA Section 129(a)(5) Five-Year Review Response

C. EPA's Approach in Conducting the Five-Year Review

D. Other Proposed Amendments

E. Proposed State Plan Implementation Schedule for Existing CISWI

F. Proposed Changes to the Applicability Date of the 2000 NSPS and EG

IV. Rationale

A. Rationale for the Proposed Response to the Remand and the Proposed CAA Section 129(a)(5) Five-Year Review Response

B. Rationale for Proposed Subcategories

C. Rationale for MACT Floor Emission Limits

D. Rationale for Beyond-the-Floor Alternatives

E. Rationale for Other Proposed Amendments

V. Impacts of the Proposed Action

A. What are the primary air impacts?

B. What are the water and solid waste impacts?

C. What are the energy impacts?

D. What are the secondary air impacts?

E. What are the cost and economic impacts?

F. What are the benefits?

VI. Relationship of the Proposed Action to Section 112(c)(6) of the CAA

VII. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

B. Paperwork Reduction Act

C. Regulatory Flexibility Act

D. Unfunded Mandates Reform Act

E. Executive Order 13132: Federalism

F. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments

G. Executive Order 13045: Protection of Children From Environmental Health and Safety Risks

H. Executive Order 13211: Actions That Significantly Affect Energy Supply, Distribution or Use

I. National Technology Transfer and Advancement Act

J. Executive Order 12898: Federal Actions To Address Environmental Justice in Minority Populations and Low-Income Populations

I. General Information

A. Does the proposed action apply to me?

Regulated Entities.

Categories and entities potentially affected by the proposed action are those which operate commercial and industrial solid waste incineration (CISWI) units. The new source performance standards (NSPS) and emission guidelines (EG), hereinafter referred to as “standards,” for CISWI affect the following categories of sources:

Category

NAICS Code

Examples of potentially regulated entities

Any industrial or commercial facility using a solid waste incinerator

211, 212, 486

Mining, oil and gas exploration operations; pipeline operators.

221

Utility providers.

321, 322, 337

Manufacturers of wood products; manufacturers of pulp, paper and paperboard; manufacturers of furniture and related products.

325, 326

Manufacturers of chemicals and allied products; manufacturers of plastics and rubber products.

327

Manufacturers of cement.

333, 336

Manufacturers of machinery; manufacturers of transportation equipment.

42, 44, 45

Wholesale merchants; retail merchants.

This

table is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be affected by the proposed action. To determine whether your facility would be affected by the proposed action, you should examine the applicability criteria in 40 CFR 60.2010 of subpart CCCC and 40 CFR 60.2505 of subpart DDDD. If you have any questions regarding the applicability of the proposed action to a particular entity, contact the person listed in the preceding

FOR FURTHER INFORMATION CONTACT

section.

Note that the rule contains definitions of the subcategories of CISWI units and a list of types of combustion units that are excluded. For further discussion, see Section III.D.1 of this preamble.

B. What should I consider as I prepare my comments?

1. Submitting CBI

Do not submit information that you consider to be CBI electronically through

http://

www.regulations.gov

or e-mail. Send or deliver information identified as CBI to only the following address: Ms. Toni Jones, c/o OAQPS Document Control Officer (Room C404-02), U.S. EPA, Research Triangle Park, NC 27711, Attention Docket ID No. EPA-HQ-OAR-2003-0119. Clearly mark the part or all of the information that you claim to be CBI. For CBI information in a disk or CD-ROM that you mail to EPA, mark the outside of the disk or CD-ROM as CBI and then identify electronically within the disk or CD-ROM the specific information that is claimed as CBI. In addition to one complete version of the comment that includes information claimed as CBI, a copy of the comment that does not contain the information claimed as CBI must be submitted for inclusion in the public docket. Information marked as CBI will not be disclosed except in accordance with procedures set forth in 40 CFR part 2.

If you have any questions about CBI or the procedures for claiming CBI, please consult the person identified in the

FOR FURTHER INFORMATION CONTACT

section.

2. Tips for Preparing Your Comments

When submitting comments, remember to:

Identify the rulemaking by docket number and other identifying

information (subject heading,

Federal Register

date and page number).

Follow directions.

EPA may ask you to respond to specific questions or organize comments by referencing a Code of Federal Regulations (CFR) part or section number.

Explain why you agree or disagree; suggest alternatives and substitute language for your requested changes.

Describe any assumptions and provide any technical information and/or data that you used.

If you estimate potential costs or burdens, explain how you arrived at your estimate in sufficient detail to allow for it to be reproduced.

Provide specific examples to illustrate your concerns and suggest alternatives.

Explain your views as clearly as possible, avoiding the use of profanity or personal threats.

Make sure to submit your comments by the comment period deadline identified in the preceding section titled

DATES

3. Docket

The docket number for the proposed action regarding the CISWI NSPS (40 CFR part 60, subpart CCCC) and EG (40 CFR part 60, subpart DDDD) is Docket ID No. EPA-HQ-OAR-2003-0119.

4. Worldwide Web (WWW)

In addition to being available in the docket, an electronic copy of the proposed action is available on the WWW through the Technology Transfer Network Web site (TTN Web). Following signature, EPA posted a copy of the proposed action on the TTN's policy and guidance page for newly proposed or promulgated rules at

http://www.epa.gov/ttn/oarpg.

The TTN provides information and technology exchange in various areas of air pollution control.

II. Background

A. What is the statutory authority for these proposed rules?

Section 129 of the Clean Air Act (CAA), entitled “Solid Waste Combustion,” requires EPA to develop and adopt standards for solid waste incineration units pursuant to CAA Sections 111 and 129. Section 129(a)(1)(A) of the CAA requires EPA to establish performance standards, including emission limitations, for “solid waste incineration units” generally and, in particular, for “solid waste incineration units combusting commercial or industrial waste” (CAA Section 129(a)(1)(D)). Section 129 of the CAA defines “solid waste incineration unit” as “a distinct operating unit of any facility which combusts any solid waste material from commercial or industrial establishments or the general public” (Section 129(g)(1)). Section 129 of the CAA also provides that “solid waste” shall have the meaning established by EPA pursuant to its authority under the Resource Conservation and Recovery Act (RCRA) (Section 129(g)(6)).

Natural Resources Defense Council

EPA,

489 F. 3d 1250 (DC Cir. 2007), the United States Court of Appeals for the District of Columbia Circuit (the Court) vacated the CISWI Definitions Rule, 70 FR 55568 (September 22, 2005), which EPA issued pursuant to CAA Section 129(a)(1)(D). In that rule, EPA defined the term “commercial or industrial solid waste incineration unit” to mean a combustion unit that combusts “commercial or industrial waste.” The rule defined “commercial or industrial waste” to mean waste combusted at a unit that does not recover thermal energy from the combustion for a useful purpose. Under these definitions, only those units that combusted commercial or industrial waste and were not designed to, or did not operate to, recover thermal energy from the combustion, were subject to Section 129 standards. In vacating the rule, the Court found that the definitions in the CISWI Definitions Rule were inconsistent with the CAA. Specifically, the Court held that the term “solid waste incineration unit” in CAA Section 129(g)(1) “unambiguously include[s] among the incineration units subject to its standards any facility that combusts any commercial or industrial solid waste material at all—subject to the four statutory exceptions identified [in CAA Section 129(g)(1)].”

NRDC

EPA,

489 F.3d at 1257-58.

In response to the Court's vacatur of the CISWI Definitions rule, EPA initiated a rulemaking to define which non-hazardous secondary materials are “solid waste” for purposes of subtitle D (non-hazardous waste) of the RCRA when burned in a combustion unit. (See Advance Notice of Proposed Rulemaking (74 FR 41, January 2, 2009) soliciting comment on whether certain non-hazardous secondary materials used as alternative fuels or ingredients are solid wastes within the meaning of Subtitle D of the RCRA). That definition, in turn, would determine the applicability of CAA Section 129(a) to commercial and industrial combustion units.

In a parallel action, EPA is proposing a definition of solid waste pursuant to Subtitle D of RCRA. That action is relevant to this proceeding because some energy recovery units and kilns combust solid waste as alternative fuels. Such units that combust solid waste (as defined pursuant to Subtitle D of RCRA) would be subject to standards under the CAA Section 129 CISWI rules rather than under Section 112 rules applicable to boilers and kilns (

e.g.

cement kilns).

EPA recognizes that it has imperfect information on the exact nature of the non-hazardous secondary materials which energy recovery units and kilns combust, including, for example, information as to the provider(s) of the non-hazardous secondary materials, how much processing the non-hazardous secondary materials may have undergone, if any, and other issues potentially relevant in a determination as to whether non-hazardous secondary materials are solid waste, as the Administrator has proposed to define that term under RCRA. We nevertheless used the information currently available to EPA to determine which materials are solid waste, the burning of which would subject a unit to CAA Section 129, and which materials are not solid waste. Energy recovery units and kilns that are burning non-hazardous secondary materials that are not solid waste would be subject to the standard under CAA Section 112 that is applicable to such units. We based the standards in this proposed rule on the sources we determined would be subject to CISWI because they combust solid waste as defined in EPA's proposed Solid Waste Definition Rulemaking, which, as noted above, is being proposed in parallel with this proposed rule.

Sections 111(b) and 129(a) of the CAA (NSPS program) address emissions from new CISWI units and CAA Sections 111(d) and 129(b) (EG program) address emissions from existing CISWI units. The NSPS are directly enforceable Federal regulations and under CAA Section 129(f)(1) become effective six months after promulgation. Under CAA Section 129(f)(2), the EG become effective and enforceable no later than three years after EPA approves a state plan implementing the EG or five years after the date they are promulgated, whichever is earlier.

The CAA sets forth a two-stage approach to regulating emissions from solid waste incinerator units. The statute also provides EPA with substantial discretion to distinguish among classes, types and sizes of incinerator units within a category while setting standards. In the first stage of setting standards, CAA Section 129(a)(2) requires EPA to establish technology-based emission standards that reflect levels of control EPA determines are achievable for new and existing units, after considering costs, non-air quality health and

environmental impacts and energy requirements associated with the implementation of the standards. Section 129(a)(5) of the CAA then directs EPA to review those standards and revise them as necessary every five years. In the second stage, CAA Section 129(h)(3) requires EPA to determine whether further revisions of the standards are necessary in order to provide an ample margin of safety to protect public health.

See, e.g., NRDC and LEAN

EPA,

529 F.3d 1077, 1079-80 (DC Cir. 2008) (addressing the similarly required two-stage approach under CAA Sections 112(d) and (f) and upholding EPA's implementation of same).

In setting forth the methodology EPA must use to establish the first-stage technology-based standards, CAA Section 129(a)(2) provides that standards “applicable to solid waste incineration units promulgated under Section 111 and this section shall reflect the maximum degree of reduction in emissions of [certain listed air pollutants] that the Administrator, taking into consideration the cost of achieving such emission reduction and any non-air quality health and environmental impacts and energy requirements, determines is achievable for new and existing units in each category.” This level of control is referred to as a maximum achievable control technology, or MACT standard.

In promulgating a MACT standard, EPA must first calculate the minimum stringency levels for new and existing solid waste incineration units in a category, generally based on levels of emissions control achieved or required to be achieved by the subject units. The minimum level of stringency is called the MACT “floor,” and CAA Section 129(a)(2) sets forth differing levels of minimum stringency that EPA's standards must achieve, based on whether they regulate new and reconstructed sources, or existing sources. For new and reconstructed sources, CAA Section 129(a)(2) provides that the “degree of reduction in emissions that is deemed achievable * * * shall not be less stringent than the emissions control that is achieved in practice by the best controlled similar unit, as determined by the Administrator.” Emissions standards for existing units may be less stringent than standards for new units, but “shall not be less stringent than the average emissions limitation achieved by the best performing 12 percent of units in the category.”

The MACT floors form the least stringent regulatory option EPA may consider in the determination of MACT standards for a source category. EPA must also determine whether to control emissions “beyond-the-floor,” after considering the costs, non-air quality health and environmental impacts and energy requirements of such more stringent control.

In general, all MACT analyses involve an assessment of the emissions from the best performing units in a source category. The assessment can be based on actual emissions data, knowledge of the air pollution control in place in combination with actual emissions data, or on state regulatory requirements that may enable EPA to estimate the actual performance of the regulated units. For each source category, the assessment involves a review of actual emissions data with an appropriate accounting for emissions variability. Other methods of estimating emissions can be used provided that the methods can be shown to provide reasonable estimates of the actual emissions performance of a source or sources. Where there is more than one method or technology to control emissions, the analysis may result in a series of potential regulations (called regulatory options), one of which is selected as MACT.

Each regulatory option EPA considers must be at least as stringent as the CAA's minimum stringency “floor” requirements. EPA must examine, but is not necessarily required to adopt, more stringent “beyond-the-floor” regulatory options to determine MACT. Unlike the floor minimum stringency requirements, EPA must consider various impacts of the more stringent regulatory options in determining whether MACT standards are to reflect “beyond-the-floor” requirements. If EPA concludes that the more stringent regulatory options have unreasonable impacts, EPA selects the “floor-based” regulatory option as MACT. But if EPA concludes that impacts associated with “beyond-the-floor” levels of control are acceptable in light of additional emissions reductions achieved, EPA selects those levels as MACT.

As stated earlier, the CAA requires that MACT for new sources be no less stringent than the emissions control achieved in practice by the best controlled similar unit. Under CAA Section 129(a)(2), EPA determines the best control currently in use for a given pollutant and establishes one potential regulatory option at the emission level achieved by that control with an appropriate accounting for emissions variability. More stringent potential beyond-the-floor regulatory options might reflect controls used on other sources that could be applied to the source category in question.

For existing sources, the CAA requires that MACT be no less stringent than the average emissions limitation achieved by the best performing 12 percent of units in a source category. EPA must determine some measure of the average emissions limitation achieved by the best performing 12 percent of units to form the floor regulatory option. More stringent beyond-the-floor regulatory options reflect other or additional controls capable of achieving better performance.

B. What are the primary sources of emissions and what are the emissions and current controls?

We are proposing to define a CISWI unit as any combustion unit at a commercial or industrial facility that is used to combust solid waste (as defined under the RCRA).

See

proposed 40 CFR 60.2265 (NSPS) and 60.2875 (EG). In this proposed rule, CISWI units include incinerators designed to discard waste materials; energy recovery units (

e.g.,

units that would be boilers if they did not burn solid waste) designed for heat recovery that combust solid waste materials; kilns and other industrial units that combust solid waste materials in the manufacture of a product; and burn-off ovens that combust residual materials off racks, parts, drums or hooks so that those items can be re-used in various production processes.

Combustion of solid waste causes the release of a wide array of air pollutants, some of which exist in the waste feed material and are released unchanged during combustion and some of which are generated as a result of the combustion process itself. These pollutants include particulate matter (PM); metals, including lead (Pb), cadmium (Cd) and mercury (Hg); toxic organics, including chlorinated dibenzo-p-dioxins/dibenzofurans (dioxin, furans); carbon monoxide (CO); nitrogen oxides (NO

); and acid gases, including hydrogen chloride (HCl) and sulfur dioxide (SO

Depending on the type of unit and currently applicable regulations or permit conditions, units may or may not be equipped with add-on control devices to control emissions. For example, most of the CISWI units that operate without heat recovery are not equipped with add-on controls. Those that are controlled use wet scrubbers, dry scrubbers, electrostatic precipitators (ESPs), or fabric filters, either alone or in combination. Some energy recovery units that combust solid waste are not equipped with add-on controls, but most are controlled with one or more of the following: cyclones or multi-clones, fabric filters, ESPs, wet scrubbers,

venturi scrubbers, selective non-catalytic reduction (SNCR) or spray dryers. In addition to add-on controls, many CISWI units are controlled through the use of pollution prevention measures (

i.e.,

waste segregation) and good combustion control practices.

Waste segregation is the separation of certain components of the waste stream in order to reduce the amount of air pollution emissions associated with that waste when incinerated. The separated waste may include paper, cardboard, plastics, glass, batteries or metals. Separation of wastes can reduce the amount of chlorine- and metal-containing wastes being incinerated, which results in lower emissions of HCl, dioxin, furans, Hg, Cd and Pb.

Good combustion control practices include proper design, construction, operation and maintenance practices to destroy or prevent the formation of air pollutants prior to their release to the atmosphere. Test data for other types of combustion units indicate that as secondary chamber residence time and temperature increase, emissions decrease. Proper mixing of flue gases in the combustion chamber also promotes complete combustion. Combustion control is most effective in reducing dioxin, furans, other organic pollutants, PM, NO

and CO emissions.

The 2000 CISWI standards and the proposed revised standards are designed to reduce air pollutants, including HCl, CO, Pb, Cd, Hg, PM, dioxin, furans (total, or 2,3,7,8-tetrachlorinated dibenzo-p-dioxin toxic equivalent (TEQ)), NO

and SO

, emitted from new and existing CISWI units. Units in the incinerator subcategory as defined in this proposed rule are currently subject to the 2000 CISWI standards and are already required to be in compliance with the NSPS or EG. The 2000 CISWI NSPS apply to CISWI units in the incinerator subcategory if construction of a unit began after November 30, 1999, or if modification of a unit began after June 1, 2001. The 2000 CISWI NSPS apply to units in the incinerator subcategory and became effective on June 1, 2001, and apply as of that date or at start-up of a CISWI incinerator unit, whichever is later. The 2000 CISWI EG apply to CISWI units in the incinerator subcategory if construction of a unit began on or before November 30, 1999, and compliance was required at the latest by December 2005. This proposed rule would establish revised standards for units in the incinerator subcategory and establish standards for the other four subcategories of CISWI units, and the emission limitations in the proposed revised NSPS and EG would apply at all times.

C. What is the relationship between this proposed rule and other combustion rules?

This proposed rule addresses the combustion of solid waste materials (as defined by the Administrator under the RCRA) in combustion units at commercial and industrial facilities. If an owner or operator of a CISWI unit ceases combusting solid waste, the affected unit would no longer be subject to this regulation under CAA Section 129. A rulemaking under CAA Section 112 is being proposed in a parallel action that is relevant to this action because it would apply to boilers and process heaters located at a major source that do not combust solid waste. EPA has also proposed, but not yet finalized, revised Section 112 National Emission Standards for Hazardous Air Pollutants (NESHAP) for cement kilns.

See

74 FR 21136 (May 6, 2009) (proposing revisions to 40 CFR part 63, Subpart LLL). Cement kilns burning solid waste would be subject to this proposed rule, not the applicable NESHAP.

III. Summary of the Proposed Rule

A. Litigation and Proposed Remand Response

1. What is the history of the CISWI standards?

On December 1, 2000, EPA published a notice of final rulemaking establishing the NSPS and EG for CISWI units (60 FR 75338), hereinafter referred to as the 2000 CISWI rule. Thereafter, on August 17, 2001, EPA granted a request for reconsideration, pursuant to CAA Section 307(d)(7)(B) of the CAA, submitted on behalf of the National Wildlife Federation and the Louisiana Environmental Action Network, related to the definition of “commercial and industrial solid waste incineration unit” and “commercial or industrial waste” in EPA's CISWI rulemaking. In granting the petition for reconsideration, EPA agreed to undertake further notice and comment proceedings related to these definitions. In addition, on January 30, 2001, the Sierra Club filed a petition for review in the U.S. Court of Appeals for the District of Columbia Circuit challenging EPA's final CISWI rule. On September 6, 2001, the Court entered an order granting EPA's motion for a voluntary remand of the CISWI rule, without vacatur. EPA's request for a voluntary remand of the final CISWI rule was taken to allow the EPA to address concerns related to EPA's procedures for establishing MACT floors for CISWI units in light of the Court's decision in

Cement Kiln Recycling Coalition

EPA,

255 F.3d 855 (DC Cir. 2001) (

Cement Kiln

). Neither EPA's granting of the petition for reconsideration, nor the Court's order granting a voluntary remand, stayed, vacated or otherwise influenced the effectiveness of the 2000 CISWI rule. Specifically, CAA Section 307(d)(7)(B) provides that “reconsideration shall not postpone the effectiveness of the rule,” except that “[t]he effectiveness of the rule may be stayed during such reconsideration * * * by the Administrator or the court for a period not to exceed three months.” Neither EPA nor the Court stayed the effectiveness of the final CISWI regulations in connection with the reconsideration petition. In addition, the District of Columbia Circuit granted EPA's motion for a remand without vacatur; therefore, the Court's remand order had no impact on the implementation of the 2000 CISWI rule.

On February 17, 2004, EPA published a proposed rule soliciting comments on the definitions of “solid waste,” “commercial and industrial waste,” and “commercial and industrial solid waste incineration unit.” On September 22, 2005, EPA published in the

Federal Register

the final rule reflecting our decisions with respect to the CISWI Definitions Rule. The rule was challenged and, on June 8, 2007, the Court vacated and remanded the CISWI Definitions Rule. In vacating the rule, the Court found that CAA Section 129 unambiguously includes among the incineration units subject to its standards any facility that combusts any solid waste material at all, subject to four statutory exceptions. While the Court vacated the CISWI Definitions Rule, the 2000 CISWI rule remains in effect.

This action provides EPA's response to the voluntary remand of the 2000 CISWI rule and to the 2007 vacatur and remand of the CISWI Definitions Rule. In addition, this action addresses the five-year technology review that is required under CAA Section 129(a)(5).

2. What was EPA's MACT floor methodology in the 2000 CISWI rulemaking and how has the methodology been changed to respond to the voluntary remand?

In 2000, the methodology that EPA followed to establish the MACT floors included identification of a “MACT floor technology” and calculation of MACT floors using emission information from all units, not only the best performing units, that employed the MACT floor control technology. EPA recognized that this methodology was rejected by the Court in the

Cement Kiln

case, which was decided after EPA

promulgated the 2000 CISWI standards. In light of the court decision, EPA requested a voluntary remand of the CISWI standards to re-evaluate those standards in light of the

Cement Kiln

decision in order to correct the methodology. See

Cement Kiln,

255 F.3d 855 (Finding that EPA is permitted to account for variability by setting floors at a level that reasonably estimates the performance of the best controlled similar unit (or units) under the worst reasonably foreseeable circumstances, but not the worst foreseeable circumstances faced by any unit in the source category).

Accordingly, this action does not use the MACT floor methodology from 2000. Instead, we used emissions test data to calculate the MACT floors.

For existing units, we ranked individual CISWI units based on actual performance and established MACT floors based on the average of the best performing 12 percent of sources for each pollutant and subcategory, with an appropriate accounting for emissions variability. That is, the overall 3-run test average values for existing units for each pollutant were compiled and ranked to identify the best performing 12 percent of sources for each pollutant within each subcategory. Once identified, the individual test run data for these units were compiled and analyzed for variability.

EPA did receive some additional emissions data earlier this year, but due to the court-ordered deadline, we did not have time to review and evaluate that data. We intend to review the data submitted earlier this year from a quality assurance and completeness perspective and incorporate that data into the final standards, as appropriate. To the extent EPA receives additional emissions data during the comment period, EPA will assess that data as it develops the final emission standards.

As discussed in more detail in Section IV.C of this preamble, for the variability analysis, we first conducted a statistical analyses to determine whether the data used for the MACT floor calculation had a normal or log-normal distribution followed by calculation of the average and the 99th percent upper limit (UL).

The UL represents a value that 99 percent of the data in the MACT floor data population would fall below, and therefore accounts for variability between the individual test runs in the MACT floor data set. The UL is calculated by the following equation that is appropriate for small data sets:

UL = x + t(0.99,n) * s

The procedure is the same as used for the Hospital/Medical/Infectious Waste Incinerators (HMIWI) rule (74 FR 51367). While the HMIWI preamble referred to this measure as the upper confidence limit (UCL), it used the same equation. In this proposal, we refer to the measure as the UL, which is a more appropriate statistical terminology for this calculation.

Where:

x = average of the data.

t(0.99,n) = t-statistic.

n = number of data points in the population.

s = standard deviation.

The summary statistics and analyses are presented in the docket and further described in Section IV.C of this preamble. The calculated UL values for existing sources (which are based on emissions data from the best performing 12 percent of sources and evaluate variability) were selected as the proposed MACT floor emission limits for the nine regulated pollutants in each subcategory. This statistical approach is consistent with the methodology used in the October 6, 2009, Hospital/Medical/Infectious Waste Incinerators (HMIWI) rule (74 FR 51367). EPA conducted this MACT floor analysis for each pollutant for each of the five CISWI subcategories we are establishing in this proposed rule: Incinerators; energy recovery units; waste-burning kilns; burn-off ovens; and small, remote incinerators.

To determine the MACT floor for new sources, we used a UL calculation similar to that for existing sources, except the best performing unit's data within a subcategory was used to calculate the MACT floor emission limit for each pollutant instead of the average of the best performing 12 percent of units. In summary, the approach ranks individual CISWI units based on actual performance and establishes MACT floors based on the best performing source for each pollutant and subcategory, with an appropriate accounting of emissions variability. In other words, the UL was determined for the data set of individual test runs for the single best performing source for each regulated pollutant from each subcategory.

EPA also solicits comment on whether EPA should use an alternate statistical interval, the 99 percent upper prediction limit (UPL) instead of the UL. In general, a prediction interval (

e.g.,

a UPL) is useful in determining what future values are likely to be, based upon present or past background samples taken. The 99 percent UPL represents the value that one can expect the mean of future 3-run performance tests from the best-performing 12 percent of sources to fall below with 99 percent confidence, based upon the results of the independent sample of observations from the same best performing sources. The 99 percent UPL value based on the test run data for those units in the best-performing 12 percent could be calculated using one of the following spreadsheet equations depending on the distribution of data:

Normal distribution: 99% UPL = AVERAGE(Test Runs in Top 12%) + [STDEV(Test Runs in Top 12%) × TINV(2 × probability, n-1 degrees of freedom) × SQRT((1/n) + (1/m))], for a one-tailed upper prediction limit with a probability of 0.01, sample size of n and number of runs whose average will be reported to EPA for compliance of m = 3.

Lognormal distribution: 99% UPL = EXP{AVERAGE(Natural Log Values of Test Runs in Top 12%) + [STDEV(Natural Log Values of Test Runs in Top 12%) × TINV(2 × probability, n-1 degrees of freedom) × SQRT((1/n) + (1/m))]}, for a one-tailed upper prediction limit with a probability of 0.01, sample size of n and number of runs whose average will be reported to EPA for compliance of m = 3.

In addition to proposing standards for the nine pollutants discussed above, we are also proposing opacity standards for new and existing sources in the five subcategories as discussed below.

Test method measurement imprecision can also be a component of data variability. At very low emissions levels as encountered in the data used to support this rule, the inherent imprecision in the pollutant measurement method has a large influence on the reliability of the data underlying the regulatory floor or beyond-the-floor emissions limit. Of particular concern are those data that are reported near or below a test method's pollutant detection capability. In our guidance for reporting pollutant emissions used to support this rule, we specified the criteria for determining test-specific method detection levels. Those criteria insure that there is about a 1 percent probability of an error in deciding that the pollutant measured at the method detection level is present, when in fact, it was absent. Such a probability is also called a false positive or the alpha, Type I, error. Another view of this probability is that one is 99 percent certain of the presence of the pollutant measured at the method detection level. Because of matrix effects, laboratory techniques, sample size and other factors, method detection levels normally vary from test to test. We requested sources to identify (

i.e.,

flag) data which were measured below the method detection level and to report those values as equal to the test-specific method detection level.

Variability of data due to measurement imprecision is inherently and reasonably addressed in calculating the floor or beyond-the-floor emissions limit when the database represents multiple tests for which all of the data are measured significantly above the method detection level. That is less true

when the database includes emissions occurring below method detection capabilities and are reported as the method detection level values. The database is then truncated at the lower end of the measurement range (

i.e.,

no values reported below the method detection level) and we believe that a floor or beyond-the-floor emissions limit based on a truncated database or otherwise including values at or near the method detection level may not adequately account for data measurement variability. We did not adjust the calculated floor for the data used for this proposal; although, we believe that accounting for measurement imprecision should be an important consideration in calculating the floor or beyond-the-floor emissions limit. We request comment on approaches suitable to account for measurement variability in establishing the floor or beyond-the-floor emissions limit when based on measurements at or near the method detection level.

As noted above, the confidence level that a value measured at the detection level is greater than zero is about 99 percent. The expected measurement imprecision for an emissions value occurring at or near the method detection level is about 40 to 50 percent. Pollutant measurement imprecision decreases to a consistent relative 10 to 15 percent for values measured at a level about three times the method detection level.

One approach that we believe could be applied to account for measurement variability would require defining a method detection level that is representative of the data used in establishing the floor or beyond-the-floor emissions limits and also minimizes the influence of an outlier test-specific method detection level value. The first step in this approach would be to identify the highest test-specific method detection level reported in a data set that is also equal to or less than the floor or beyond-the-floor emissions limit calculated for the data set. This approach has the advantage of relying on the data collected to develop the floor or beyond-the-floor emissions limit while to some degree minimizing the effect of a test(s) with an inordinately high method detection level (

e.g.,

the sample volume was too small, the laboratory technique was insufficiently sensitive or the procedure for determining the detection level was other than that specified).

American Society of Mechanical Engineers,

Reference Method Accuracy and Precision (ReMAP): Phase 1, Precision of Manual Stack Emission Measurements,

CRTD Vol. 60, February 2001.

The second step would be to determine the value equal to three times the representative method detection level and compare it to the calculated floor or beyond-the-floor emissions limit. If three times the representative method detection level was less than the calculated floor or beyond-the-floor emissions limit, we would conclude that measurement variability is adequately addressed and we would not adjust the calculated floor or beyond-the-floor emissions limit. If, on the other hand, the value equal to three times the representative method detection level was greater than the calculated floor or beyond-the-floor emissions limit, we would conclude that the calculated floor or beyond-the-floor emissions limit does not account entirely for measurement variability. We then would use the value equal to three times the method detection level in place of the calculated floor or beyond-the-floor emissions limit to ensure that the floor or beyond-the-floor emissions limit accounts for measurement variability. We request comment on this approach.

As stated above, EPA's solid waste definition rule proposes to define which non-hazardous secondary materials that are used as fuels or ingredients in combustion units are solid wastes under Subtitle D of RCRA. In addition to the primary proposed approach set forth in the Solid Waste Definition rule, the rule solicits comments on an alternative approach for determining which secondary materials are solid waste under Subtitle D of RCRA, when combusted. The MACT analysis discussed above considers only those commercial or industrial units that are CISWI units (

i.e.,

that are units that combust “solid waste” as that term is defined by the Administrator under RCRA). Based on the MACT analysis described above, we calculated emission standards under both the primary proposed approach and the alternative approach identified in the proposed Solid Waste Definition rule. The only two subcategories for which the number of units changed under the alternative approach set forth in the solid waste definition rule were the energy recovery units and waste-burning kilns subcategories. Because the number of units in these two subcategories is different under the alternative approach, the NSPS and EG did change. Based on the information available to EPA, the number of units in the other subcategories (

i.e.,

incinerators, burn-off ovens and small, remote incinerators) remained the same under both the proposed and alternative approaches, and the NSPS and EG, therefore, did not change under the alternative approach.

Table 1 of this preamble shows a comparison of the existing source MACT limits from the 2000 CISWI rule and those developed for the five subcategories in this action based on the proposed definition of solid waste. EPA did not establish subcategories in the 2000 CISWI rule and, for that reason, a direct comparison with the standards proposed today with the 2000 standards is only possible for the incinerators subcategory. As stated above, we are proposing to subcategorize CISWI units for reasons described in Section IV.B of this preamble. The five subcategories are:

• Incinerators, which are those units that are currently regulated by the 2000 CISWI rule, are units that are used to dispose of solid waste materials.

• Energy recovery units that combust solid waste materials as a percentage of their fuel mixture. Energy recovery units include units that would be boilers or process heaters if they did not combust solid waste.

• Waste-burning kilns means a kiln that is heated, in whole or in part, by combusting solid waste (as that term is defined by the Administrator under RCRA).

• Burn-off ovens that are used to clean residual solid waste materials off of various metal parts which are then reused.

• Small, remote incinerators that combust less than one ton of waste per day and are farther than 50 miles driving distance to the closest municipal solid waste (MSW) landfill.

The proposed MACT floor emission limits for existing sources in each subcategory are shown in Table 1 of this preamble.

Table 1—Comparison of Existing Source MACT Floor Limits for 2000 CISWI Rule and the Proposed MACT Floor Limits

[Based on the primary proposed definition of solid waste in the Solid Waste Definition Rule]

Pollutant (units)

Incinerators (2000 CISWI limit)

Proposed CISWI subcategories

Incinerators

Energy

recovery units

Waste-burning kilns

Burn-off ovens

Small, remote incinerators

HCl (ppmv)

1.5

130

150

CO (ppmv)

157

2.2

150

710

Pb (mg/dscm)

0.04

0.0026

0.002

0.0027

0.041

1.4

Cd (mg/dscm)

0.004

0.0013

0.00041

0.0003

0.0045

0.26

Hg (mg/dscm)

0.47

0.0028

0.00096

0.024

0.014

0.0029

PM, filterable (mg/dscm)

9.2

240

dioxin, furans, total (ng/dscm)

(no limit)

0.031

0.75

2.1

310

1,600

dioxin, furans, TEQ (ng/dscm)

0.41

0.0025

0.059

0.17

130

(ppmv)

388

130

1,100

120

210

(ppmv)

2.5

4.1

410

Opacity (%)

All emission limits are measured at 7% oxygen.

ppmv = parts per million by volume.

mg/dscm = milligrams per dry standard cubic meter.

ng/dscm = nanograms per dry standard cubic meter.

After establishing the MACT floors for each subcategory and pollutant, EPA also assessed options more stringent than the MACT floors. For reasons described in the rationale section (IV) of the preamble, we are not proposing limits more stringent than the MACT floor. However, we are proposing to amend the requirements to qualify for reduced testing and, thereby, we are providing an incentive for owners or operators to optimize a unit's carbon injection system and other operating parameters to further reduce both mercury and dioxin/furan emissions.

As stated above, the approach for new sources was similar to that used with the existing sources, except the best performing unit's data within a subcategory was used to calculate the MACT floor emission limit instead of the average of the best performing 12 percent of units. In summary, the approach ranks individual CISWI units based on actual performance and establishes MACT floors based on the best performing source for each pollutant and subcategory, with an appropriate accounting for emissions variability. The new source MACT floor emission limits for each CISWI subcategory are shown in Table 2 of this preamble.

Table 2—Comparison of New Source MACT Floor Limits for 2000 CISWI Rule and the Proposed MACT Floor Limits

[Based on the primary definition of solid waste in the Solid Waste Definition Rule]

Pollutant (units)

Incinerators (2000 limit)

Proposed CISWI subcategories

Incinerators

Energy

recovery units

Waste-burning kilns

Burn-off ovens

Small, remote incinerators

HCl (ppmv)

0.074

0.17

1.5

150

CO (ppmv)

157

1.4

3.0

4.0

Pb (mg/dscm)

0.04

0.0013

0.0012

0.00078

0.029

1.4

Cd (mg/dscm)

0.004

0.00066

0.00012

0.00030

0.0032

0.057

Hg (mg/dscm)

0.47

0.00013

0.024

0.0033

0.0013

PM, filterable (mg/dscm)

0.0077

4.4

1.8

240

dioxin, furans, total (ng/dscm)

(no limit)

0.0093

0.034

0.00035

0.011

1,200

dioxin, furans, TEQ (ng/dscm)

0.41

0.00073

0.0027

0.000028

0.00086

(ppmv)

388

140

210

(ppmv)

1.5

4.1

3.6

1.5

Opacity (%)

All emission limits are measured at 7 percent oxygen.

3. How is the solid waste definition addressed in this proposed rule?

EPA is proposing to define the non-hazardous secondary materials that are solid waste in a parallel notice under RCRA and the RCRA proposal also identifies an “alternative approach” for consideration and comment. The concurrently proposed RCRA solid waste definition is integral in defining the CISWI source category. As stated above, the emission limits presented in Tables 1 and 2 of this preamble are based on subcategories established considering sources that are CISWI units under the “proposed approach” for defining when non-hazardous secondary materials are solid waste, as discussed in a parallel proposal under RCRA. As stated above, the “alternative approach” identified for consideration and comment in the RCRA notice would result in a different population of units being covered by the standards for two of the CISWI subcategories. We calculated MACT floors using emission rates for units that would be CISWI units under the “alternative approach” (

i.e.,

for units in the energy recovery units and waste-burning kilns

subcategories) and the MACT standard setting procedures previously described.

Table 3 of this preamble reflects the potential MACT floor limits for the subcategories (

i.e.,

energy recovery unit and waste-burning kiln) that would be affected considering the “alternative approach” for defining solid waste. The MACT floor limits for the remaining three subcategories would not be impacted by the “alternative approach” and are reflected in Tables 1 and 2 of this preamble.

Table 3—Potential New and Existing MACT Floor Limits for the Energy Recovery Units and Waste-Burning Kiln Subcategories Using the “Alternative Approach” Under Consideration and Comment in the Concurrently Proposed RCRA Rule

Pollutant

(units)

Proposed MACT floor for existing units

Energy

recovery units

Waste-burning kilns

Proposed MACT floor for new units

Energy

recovery units

Waste-burning kilns

HCl (ppmv)

3.6

0.036

3.6

CO (ppmv)

290

760

Pb (mg/dscm)

0.15

0.0061

0.000023

0.00078

Cd (mg/dscm)

0.013

0.00070

0.0000011

0.00070

Hg (mg/dscm)

0.0085

0.03

0.00013

0.00081

PM, filterable (mg/dscm)

3.4

1.8

dioxin, furans, total (ng/dscm)

2.2

0.0017

0.00035

dioxin, furans, TEQ (ng/dscm)

7.5

0.18

0.00014

0.000028

(ppmv)

440

1,100

140

(ppmv)

1,500

410

0.040

3.6

Opacity (%)

All emission limits are measured at 7 percent oxygen.

B. Proposed CAA Section 129(a)(5) Five-Year Review Response

Section 129(a)(5) of the CAA requires EPA to conduct a review of the standards at five-year intervals and, in accordance with CAA Sections 129 and 111, revise the standards. We do not interpret CAA Section 129(a)(5), together with CAA Section 111, as requiring EPA to recalculate MACT floors in connection with this periodic review. See,

e.g.,

71 FR 27324, 27327-28 (May 10, 2006) “Standards of Performance for New Stationary Sources and Emission Guidelines for Existing Sources: Large Municipal Waste Combustors; Final Rule”; see also,

NRDC and LEAN

EPA,

529 F.3d 1077, 1083-84 (D.C. Cir. 2008) (upholding EPA's interpretation that the periodic review requirement in CAA Section 112(d)(6) does not impose an obligation to recalculate MACT floors).

Rather, in conducting such periodic reviews, EPA attempts to assess the performance of and variability associated with control measures affecting emissions performance at sources in the subject source category (including the installed emissions control equipment), along with recent developments in practices, processes and control technologies, and determines whether it is appropriate to revise the standards. This is the same general approach taken by EPA in periodically reviewing CAA Section 111 standards, as CAA Section 111 contains a similar review and revise provision. Specifically, CAA Section 111(b)(1)(B) requires EPA, except in specified circumstances, to review NSPS promulgated under CAA Section 111 every eight years and to revise the standards if EPA determines that it is “appropriate” to do so, 42 U.S.C. 7411(b)(1)(B). In light of the explicit reference in CAA Section 129(a)(5) to Section 111, which contains direct guidance on how to review and revise standards previously promulgated, EPA reasonably interprets CAA Section 129(a)(5) to provide that EPA must similarly review and, if appropriate, revise CAA Section 129 standards.

Section 129 provides guidance on the criteria to be used in determining whether it is appropriate to revise a CAA Section 129 standard. Section 129(a)(3) states that standards under CAA Sections 111 and 129 “shall be based on methods and technologies for removal or destruction of pollutants before, during and after combustion.” It can be reasonably inferred from the reference to “technologies” that EPA is to consider advances in technology, both as to their effectiveness and their costs, as well as the availability of new technologies, in determining whether it is “appropriate” to revise a CAA Section 129 standard. This inference is further supported by the fact that the standards under review are based, in part, on an assessment of the performance of control technologies currently being used by sources in a category or subcategory.

This approach is also consistent with the approach used in establishing and updating NSPS under CAA Section 111. Consistent with the definition of “standard of performance” in CAA Section 111(a)(1), standards of performance promulgated under CAA Section 111 are based on “the best system of emission reductions” which generally equates to some type of control technology. Where EPA determines that it is “appropriate” to revise CAA Section 111 standards, CAA Section 111(b)(1)(B) directs that this be done “following the procedure required by this subsection for promulgation of such standards.” In updating CAA Section 111 standards in accordance with CAA Section 111(b)(1)(B), EPA has consistently taken the approach of evaluating advances in existing control technologies, both as to performance and cost, as well as the availability of new technologies and then, on the basis of this evaluation, determined whether it is appropriate to revise the standard.

See,

for example, 71 FR 9866 (Feb. 27, 2006) (updating the boilers NSPS) and 71 FR 38482 (July 6, 2006) (updating the stationary combustion turbines NSPS). In these reviews, EPA takes into account, among other things, the currently installed equipment and its performance and operational variability. As appropriate, we also consider new technologies and control measures that have been demonstrated to reliably control emissions from the source category.

The approach is similar to the one that Congress spelled out in CAA Section 112(d)(6), which is also entitled

“Review and revision.” Section 112(d)(6) directs EPA to every eight years “review, and revise as necessary (taking into account developments in practices, processes and control technologies)” emission standards promulgated pursuant to CAA Section 112. There are a number of significant similarities between what is required under CAA Section 129, which addresses emissions of hazardous air pollutants (HAP) and other pollutants from solid waste incineration units, and CAA Section 112, which addresses HAP emissions generally. For example, under both CAA Section 112(d)(3) and CAA Section 129(a)(2) initial standards applicable to existing sources “shall not be less stringent than the average emissions limitation achieved by the best performing 12 percent of units in the category.” Also, as stated above, both sections require that standards be reviewed at specified intervals of time. Finally, both sections contain a provision addressing “residual risk” (CAA Sections 112(f) and 129(h)(3)). As a result, EPA believes that CAA Section 112(d)(6) is relevant in ascertaining Congress' intent regarding how EPA is to proceed in implementing CAA Section 129(a)(5).

Like its counterpart CAA Section 112(d)(6), Section 129(a)(5) does not state that EPA must conduct a MACT floor analysis every five years when reviewing standards promulgated under CAA Sections 129(a)(2) and 111. Had Congress intended EPA to conduct a new floor analysis every five years, it would have said so expressly by directly incorporating such requirements into CAA Section 129(a)(5), for example, by referring directly to CAA Section 129(a)(2), rather than just to “this section” and CAA Section 111. It did not do so, however, and, in fact, CAA Section 129 encompasses more than just MACT standards under CAA Section 129(a)(2)—it also includes risk-based standards under CAA Section 129(h)(3), which are not determined by an additional MACT analysis. Reading CAA Section 129(a)(5) to require recalculation of the MACT floor would be both inconsistent with Congress' express direction that EPA should revise CAA Section 129 standards in accordance with CAA Section 111, which plainly provides that such revision should occur only if we determine that it is “appropriate” to do so. It would also result in effectively reading the reference to CAA Section 111 out of the CAA, a circumstance that Congress could not have intended. Required recalculation of floors would completely eviscerate EPA's ability to base revisions to CAA Section 129 standards on a determination that it is “appropriate” to revise such standards, as EPA's only discretion would be in deciding whether to establish a standard that is more stringent than the recalculated floor. EPA believes that depriving the Agency of any meaningful discretion in this manner is at odds with what Congress intended.

Further, required recalculation of floors would have the inexorable effect of driving existing sources to the level of performance exhibited by new sources on a five-year cycle, a result that is unprecedented and that should not be presumed to have been intended by Congress in the absence of a clear statement to that effect. There is no such clear statement. It is reasonable to assume that if the floor must be recalculated on a five-year cycle, some, if not most or all, of the sources that form the basis for the floor calculation, will be sources that were previously subject to standards applicable to new sources. As a result, over time, existing sources which had not made any changes in their operations, would eventually be subject to essentially the same level of regulation as new sources. Such a result would be unprecedented, particularly in the context of a standard that is established under both CAA Sections 129 and 111. Under CAA Section 111, an existing source only becomes a new source and thus subject to a new source standard when it is either modified (CAA Section 111(a)(2)) or reconstructed (40 CFR 60.15). Given this context, it is not reasonable to assume that Congress intended for existing sources subject to CAA Section 129 standards to be treated as new sources over time where their circumstances have not changed.

We believe that a reasonable interpretation of CAA Section 129(a)(5) is that Congress preserved EPA's discretion in reviewing CAA Section 129 standards to revise them when the EPA determines it is “appropriate” to do so and that the Court's recent ruling regarding CAA Section 112(d)(6) supports this view (

see NRDC and LEAN

EPA,

529 F.3d 1077, 1084 (DC Cir. 2008). In that case, petitioners had “argued that EPA was obliged to completely recalculate the maximum achievable control technology—in other words, to start from scratch.”

NRDC and LEAN,

529 F.3d at 1084. The Court held: “We do not think the words `review, and revise as necessary' can be construed reasonably as imposing any such obligation.” The Court's ruling in

NRDC and LEAN

is consistent with our interpretation of CAA Section 129(a)(5) as providing a broad range of discretion in terms of whether to revise MACT standards adopted under CAA Sections 129(a)(2) and 111.

C. EPA's Approach in Conducting the Five-Year Review

This action responds to the vacatur and remand of the CISWI Definition Rule and the voluntary remand of the 2000 CISWI NSPS and EG, and, in this response, EPA is proposing new standards based on a MACT methodology that is consistent with the CAA and District of Columbia Circuit Court precedent. The MACT levels proposed herein reflect floor levels determined by actual current emissions data from CISWI units, and, therefore, reflect the current performance of the best performing unit or units that will be subject to the CISWI standards. Consequently, we believe that our obligation to conduct a five-year review based on implementation of the 2000 CISWI rule will also be fulfilled upon finalization of the CISWI standards. Our conclusion is supported by the fact that the revised MACT standards included in this proposed remand response are based on the available performance data for the currently operating CISWI units, including those units that are subject to the 2000 CISWI rule and those units that will be subject to the CISWI standards for the first time based on the proposed Solid Waste Definition rule under RCRA. In establishing MACT floors based on currently available emissions information, we address the technology review's goals of assessing the performance efficiency of the installed equipment and ensuring that the emission limits reflect the performance of the technologies required by the MACT standards. In addition, in establishing the proposed standards, we considered whether new technologies and processes and improvements in practices have been demonstrated at sources subject to the 2000 CISWI rule and at sources that will be subject to these proposed standards for the first time based on the proposed definition of solid waste. Accordingly, the remand response in this proposed action fulfills EPA's obligations regarding the five-year review of the CISWI standards.

D. Other Proposed Amendments

This proposed action makes additional changes to the 2000 CISWI rule, including changes to the units excluded from regulation under the 2000 CISWI rule; the removal of the exemption for periods of startup, shutdown and malfunction; changes to the testing, monitoring and reporting requirements; and changes to the

electronic data submittal requirements. A summary of these changes follows.

1. Definitions and Units Excluded From Regulation

We are revising the definition of CISWI unit to reflect the Court decision that all units burning solid waste as defined under RCRA are to be covered by regulation under CAA Section 129. We are also adding a definition of “solid waste incineration unit” and removing the definition of “commercial and industrial waste”. We also included for the first time definitions of the five subcategories of CISWI units that will be regulated under the proposed rules.

The 2000 CISWI rule excluded from regulation combustion units at commercial or industrial facilities that recovered energy for a useful purpose, and also excluded multiple other types of units that may combust solid waste including: Pathological waste incinerators; agricultural waste incinerators; incinerators regulated by the CAA Section 129 municipal waste combustor (MWC) or HMIWI standards; incinerators with a capacity less than 35 tons per day that combust more than 30 percent MSW; qualifying small power producers; qualifying cogeneration units; materials recovery units; air curtain incinerators combusting “clean wood” waste; cyclonic barrel burners; rack, part and drum reclamation units; cement kilns; sewage sludge incinerators (SSI); chemical recovery units; and laboratory analysis units.

Qualifying small power producers, qualifying cogeneration units and metals recovery units are expressly exempt from coverage pursuant to CAA exclusions from the definition of “solid waste incineration unit” set forth in Section 129(g)(1). Units that are required to have a permit under section 3005 or the Solid Waste Disposal Act (

i.e.,

hazardous waste combustion units) are also exempt from Section 129 rules per CAA Section 129(g)(1). Air curtain incinerators at commercial or industrial facilities combusting “clean wood” waste are also excluded from the definition of solid waste incineration unit set forth in CAA Section 129(g)(1), but that section provides that such units must comply with opacity limits.

Solid waste incineration units that are included within the scope of other CAA Section 129 categories include MWCs, pathological waste incinerators (EPA intends to regulate these units under other solid waste incineration (OSWI) standards), SSI (EPA currently intends to issue a regulation setting emission standards for these units by December 16, 2010), and HMIWI, and these solid waste incineration units will remain exempt from the CISWI standards. All other solid waste incineration units at commercial and industrial facilities would be subject to the proposed CISWI standards. Accordingly, the proposed revisions to the CISWI rules would remove the exemptions for: Agricultural waste incinerators; cyclonic barrel burners; cement kilns; rack, part and drum reclamation units (

i.e.

burn-off ovens); chemical recovery units; and laboratory analysis units. As stated above, we are proposing to create subcategories for waste-burning kilns, energy recovery units and burn-off ovens and subject them to this proposed rule in light of the CISWI Definitions Rule vacatur. We note that other Section 129 standards may contain an exemption for cement kilns. Those exemptions do not excuse waste burning kilns from compliance with these proposed standards. As those other Section 129 rules are amended, we will clarify that cement kilns that meet the definition of waste-burning kiln and other CISWI units that may be expressly exempt from those standards are subject to CISWI standards if they combust solid waste.

CISWI units burning agricultural materials that meet the definition of solid waste would be part of the appropriate standards under this proposed rule. If the unit recovers energy, it would be subject to the CISWI energy recovery unit subcategory, and our inventory includes one such unit. If the unit does not recover energy, it would be included in either the incinerators subcategory or the small, remote incinerators subcategory. We are not aware of any circumstances in which waste-burning kilns or burn off ovens would combust agricultural materials. Cyclonic burn barrels, which may be used to combust agricultural materials, would be included in either the incinerators subcategory or the small remote incinerators subcategory.

2. Performance Testing and Monitoring Amendments

The proposed amendments would require all CISWI units to demonstrate initial compliance with the revised emission limits. The proposed amendments would require, for existing CISWI units, annual inspections of scrubbers, fabric filters and other air pollution control devices that are used to meet the emission limits. In addition, a Method 22 of appendix A-7 visible emissions test of the ash handling operations is required to be conducted during the annual compliance test for all subcategories except waste-burning kilns, which do not have ash handling systems. Furthermore, for any existing CISWI unit that operates a fabric filter air pollution control device, we are proposing that a bag leak detection system be installed to monitor the device. The proposed amendments continue to require parametric monitoring of all other add-on air pollution control devices, such as wet scrubbers and activated carbon injection. CISWI units that install SNCR technology to reduce NO

emissions would be required to monitor the reagent (

e.g.,

ammonia or urea) injection rate and secondary chamber temperature (if applicable to the CISWI unit).

The proposed amendments would also require subcategory-specific monitoring requirements in addition to the aforementioned inspection, bag leak detection and parametric monitoring requirements applicable to all CISWI units. Existing incinerators, burn-off ovens and small, remote incinerators would have annual emissions testing for opacity, HCl and PM. Existing kilns would monitor Hg emissions using a Hg continuous emissions monitoring systems (CEMS) and would perform annual testing for CO, NO

, SO

, PM, HCl and opacity. Existing energy recovery units would monitor CO using a CO CEMS. We seek comment on the extent to which existing units in subcategories other than energy recovery should be required to use CO CEMS. Annual performance testing for CO, NO

, SO

, PM, HCl, dioxins/furans and opacity is also required for these units. The proposed amendments provide reduced annual testing requirements for PM, HCl and opacity when testing results are shown to be well below the limits. If the energy recovery unit has a design capacity less than 250 MMBtu/hr and is not equipped with a wet scrubber control device, then a continuous opacity monitor would be required or, as an alternative, a PM CEMS could be employed (see below). If the energy recovery unit has a design capacity greater than 250 MMBtu/hr, the proposed requirements would require monitoring of PM emissions using a PM CEMS. We seek comment on the extent to which subcategories other than energy recovery units should be required to use PM CEMS.

For new CISWI units, the proposed amendments would require the same monitoring requirements proposed for existing units, but would also require CO CEMS for all subcategories.

For all subcategories of existing CISWI units, use of CO CEMS would be an approved alternative and specific language with requirements for CO CEMS is included in the proposed amendments. For new and existing

CISWI units, use of PM, NO

, SO

, HCl, multi-metals and Hg CEMS and integrated sorbent trap Hg monitoring and dioxin monitoring (continuous sampling with periodic sample analysis) also would be approved alternatives and specific language for those alternatives is included in the proposed amendments.

3. Electronic Data Submittal

The EPA must have performance test data to conduct effective reviews of CAA Section 112 and 129 standards, as well as for many other purposes including compliance determinations, emissions factor development and annual emissions rate determinations. In conducting these required reviews, we have found it ineffective and time consuming not only for us but also for regulatory agencies and source owners and operators to locate, collect and submit emissions test data because of varied locations for data storage and varied data storage methods. One improvement that has occurred in recent years is the availability of stack test reports in electronic format as a replacement for cumbersome paper copies.

In this action, we are taking a step to improve data accessibility. Owners and operators of CISWI units will be required to submit to an EPA electronic database an electronic copy of reports of certain performance tests required under this rule. Data entry will be through an electronic emissions test report structure called the Electronic Reporting Tool (ERT) that will be used by the staff as part of the emissions testing project. The ERT was developed with input from stack testing companies who generally collect and compile performance test data electronically and offices within state and local agencies which perform field test assessments. The ERT is currently available, and access to direct data submittal to EPA's electronic emissions database (WebFIRE) will become available by December 31, 2011.

The requirement to submit source test data electronically to EPA will not require any additional performance testing and will apply to those performance tests conducted using test methods that are supported by ERT. The ERT contains a specific electronic data entry form for most of the commonly used EPA reference methods. The Web site listed below contains a listing of the pollutants and test methods supported by ERT. In addition, when a facility submits performance test data to WebFIRE, there will be no additional requirements for emissions test data compilation. Moreover, we believe industry will benefit from development of improved emissions factors, fewer follow-up information requests and better regulation development as discussed below. The information to be reported is already required for the existing test methods and is necessary to evaluate the conformance to the test method.

One major advantage of submitting source test data through the ERT is that it provides a standardized method to compile and store much of the documentation required to be reported by this rule while clearly stating what testing information we require. Another important benefit of submitting these data to EPA at the time the source test is conducted is that it will substantially reduce the effort involved in data collection activities in the future. Specifically, because EPA would already have data for this source category as a result of the electronic reporting provisions described here, there would likely be fewer or less substantial data collection requests (

e.g.,

CAA Section 114 letters) in the future for this source category. This results in a reduced burden on both affected facilities (in terms of reduced manpower to respond to data collection requests) and EPA (in terms of preparing and distributing data collection requests).

State/local/tribal agencies may also benefit in that their review may be more streamlined and accurate as the states will not have to re-enter the data to assess the calculations and verify the data entry. Finally, another benefit of submitting these data to WebFIRE electronically is that these data will improve greatly the overall quality of the existing and new emissions factors by supplementing the pool of emissions test data upon which the emissions factor is based and by ensuring that data are more representative of current industry operational procedures. A common complaint we hear from industry and regulators is that emissions factors are outdated or not representative of a particular source category. Receiving and incorporating data for most performance tests will ensure that emissions factors, when updated, represent accurately the most current operational practices. In summary, receiving test data already collected for other purposes and using them in the emissions factors development program will save industry, state/local/tribal agencies and EPA time and money and work to improve the quality of emissions inventories and related regulatory decisions.

As mentioned earlier, the electronic database that will be used is EPA's WebFIRE, which is a Web site accessible through EPA's TTN. The WebFIRE Web site was constructed to store emissions test data for use in developing emissions factors. A description of the WebFIRE database can be found at

http://cfpub.epa.gov/oarweb/index.cfm?action=fire.main.

The ERT will be able to transmit the electronic report through EPA's Central Data Exchange (CDX) network for storage in the WebFIRE database. Although ERT is not the only electronic interface that can be used to submit source test data to the CDX for entry into WebFIRE, it makes submittal of data very straightforward and easy. A description of the ERT can be found at

http://www.epa.gov/ttn/chief/ert/ert_tool.html.

4. Changes to Startup, Shutdown and Malfunction Provisions

The 2000 CISWI standards did not apply during periods of startup, shutdown and malfunction. The proposed rule would revise the 2000 CISWI rule such that the standards would apply at all times, including during startup, shutdown or malfunction events. As further explained in Section IV.E.4 of this preamble, the revision is the result of a court decision that invalidated certain regulations related to startup, shutdown and malfunction in the General Provisions of 40 CFR part 63. The full rationale for these decisions is presented in Section IV.E.3 of this preamble.

E. Proposed State Plan Implementation Schedule for Existing CISWI

Under the proposed amendments to the EG and consistent with CAA Section 129, revised state plans containing the revised existing source emission limits and other requirements in the proposed amendments would be due within one year after promulgation of the amendments. That is, states would have to submit revised plans to EPA one year after the date on which EPA promulgates revised standards.

The proposed amendments to the EG would then allow existing CISWI to demonstrate compliance with the amended standards as expeditiously as practicable after approval of a state plan, but no later than three years from the date of approval of a state plan or five years after promulgation of the revised standards, whichever is earlier. Consistent with CAA Section 129, EPA expects states to require compliance as expeditiously as practicable. However, because we believe that many CISWI units will find it necessary to retrofit existing emission control equipment and/or install additional emission

control equipment in order to meet the proposed revised limits, EPA anticipates that states may choose to provide the three year compliance period allowed by CAA Section 129(f)(2).

In revising the standards in a state plan, a state would have two options. First, it could include both the 2000 CISWI standards and the new standards in its revised state plan, which would allow a phased approach in applying the new limits. That is, the state plan would make it clear that the standards in the 2000 CISWI rule remain in force for units in the incinerators subcategory and apply until the date the revised existing source standards are effective (as defined in the state plan).

States whose existing CISWI units in the incinerators subcategory do not need to improve their performance to meet the revised standards may want to consider a second approach where the state would replace the 2000 CISWI rule standards with the standards in the final rule, follow the procedures in 40 CFR part 60, subpart B, and submit a revised state plan to EPA for approval. If the revised state plan contains only the revised standards (

i.e.,

the 2000 CISWI rule standards are not retained), then the revised standards must become effective immediately for those units in the incinerators subcategory that are subject to the 2000 CISWI rule since the 2000 CISWI rule standards would be removed from the state plan.

All sources currently subject to the 2000 CISWI EG or NSPS will become existing sources in the incinerators subcategory once the final revised CISWI standards are in place. See section III.F below.

EPA will revise the existing Federal plan to incorporate any changes to existing source emission limits and other requirements that EPA ultimately promulgates. The Federal plan applies to CISWI units in any state without an approved state plan. The proposed amendments to the EG would allow existing CISWI units subject to the Federal plan up to five years after promulgation of the revised standards to demonstrate compliance with the amended standards, as required by CAA Section 129(b)(3).

F. Proposed Changes To the Applicability Date of the 2000 NSPS and EG

CISWI units in the incinerators subcategory would be treated differently under the amended standards, as proposed, than they were under the 2000 CISWI rule in terms of whether they are “existing” or “new” sources. Consistent with the CAA Section 129 definition of “new” sources, there would be new dates defining what units are “new” sources. Units in the incinerators subcategory that are currently subject to the NSPS would become “existing” sources under the proposed amended standards and would be required to meet the revised EG for the incinerators subcategory by the applicable compliance date for the revised guidelines. However, those units would continue to be NSPS units subject to the 2000 CISWI rule until they become “existing” sources under the amended standards. CISWI units in the five subcategories that commence construction after the date of this proposal, or for which a modification is commenced on or after the date six months after promulgation of the amended standards, would be “new” units subject to more stringent NSPS emission limits. Units for which construction or modification is commenced prior to those dates would be existing units subject to the proposed EG, except that units in the incinerators subcategory would remain subject to the 2000 CISWI rule until the compliance date of the proposed CISWI EG as discussed above. CISWI solid waste incineration units in the subcategories other than the incinerators subcategory will not in any case be subject to the standards in the 2000 CISWI rule.

Thus, under these proposed amendments, units in the incinerators subcategory that commenced construction after November 30, 1999, and on or before June 4, 2010, or that are reconstructed or modified prior to the date six months after promulgation of any revised final standards, would be subject to the 2000 CISWI NSPS until the applicable compliance date for the revised EG, at which time those units would become “existing” sources. Similarly, units in the incinerators subcategory subject to the EG under the 2000 CISWI rule would need to meet the revised EG by the applicable compliance date for the revised guidelines. CISWI units that commence construction after June 4, 2010 or that are reconstructed or modified six months or more after the date of promulgation of any revised standards would have to meet the revised NSPS emission limits being added to the subpart CCCC NSPS within six months after the promulgation date of the amendments or upon startup, whichever is later.

IV. Rationale

A. Rationale for the Proposed Response To the Remand and the Proposed CAA Section 129(a)(5) Five-Year Review Response

1. Rationale for the Proposed Response To the Remand Pursuant to CAA Section 129(a)(2)

The proposed revised standards represent EPA's position concerning what is necessary to satisfy our initial duties under CAA Section 129(a)(2) to have set MACT limits for CISWI and we are establishing the MACT standards in response to the voluntary remand that EPA requested in 2001 and the Court's remand of the CISWI Definitions Rule. As explained further below, we are subcategorizing CISWI units for the first time in light of the new population of units subject to the rule. Specifically, we are proposing a total of five subcategories. Below, we propose MACT standards for each subcategory of new and existing CISWI units.

See

sections II.A. and III.B above for a detailed discussion of EPA's authority to establish CAA Section 129(a)(2) standards for CISWI units.

2. Proposed CAA Section 129(a)(5) Five-Year Review Response

As stated above, EPA interprets CAA Section 129(a)(5) to provide EPA with broad discretion to revise MACT standards for incinerators. As we explained, we do not interpret CAA Section 129(a)(5), as requiring that EPA in each round of review, recalculate MACT floors, and we regard the Court's recent ruling in

NRDC and LEAN

EPA,

in which the Court held that the similar review requirement in CAA Section 112(d)(6) does not require a MACT floor recalculation, as supporting our view. This action does not reflect an independent MACT floor reassessment performed under CAA Section 129(a)(5). However, since these proposed standards do reflect the emissions levels currently achieved in practice by the best performing CISWI units and we have no other information that would cause us to reach different conclusions were a CAA Section 129(a)(5) review to be conducted in isolation, we believe that this rulemaking responding to the Court's remand will necessarily discharge our duty under CAA Section 129(a)(5) to review and revise the current standards.

In performing future five-year reviews of the CISWI standards, we do not intend to recalculate new MACT floors, but will instead propose to revise the emission limits consistent with our interpretation as presented above in

section III.B. We believe this approach reflects the most reasonable interpretation of the review requirement of CAA Section 129(a)(5), and is consistent with how we have interpreted the similar review requirement of CAA Section 112(d)(6), regarding MACT standards promulgated under CAA Section 112.

This action's proposed remand response fulfills our obligations regarding the five-year review of the CISWI standards because the revised MACT floor determinations and emission limits associated with the remand response are based on performance data for currently operating CISWI units and accounts for all non-technology factors that affect CISWI unit performance. The proposed remand response also addresses whether new technologies and processes and improvements in practices have been demonstrated at CISWI units subject to the 2000 CISWI rule. Furthermore, this action also proposes monitoring requirements for control devices that may be used to comply with the proposed standards by units in the subcategories that were not subject to the 2000 CISWI rule, but would be subject to these proposed standards. These controls include activated carbon injection, selective non-catalytic reduction and electrostatic precipitators. Our information indicates that these technologies are currently being used by some of the units that would be subject to this proposal, or have been applied to units in similar source categories, such as municipal waste combustors. We also reviewed CEMS requirements being proposed in standards for the non-waste burning counterparts to the waste-burning kiln and energy recovery unit subcategories, and believe that these can be applied to similar units that would be regulated under the proposed CISWI standards.

B. Rationale for Proposed Subcategories

As discussed earlier in section III.A.2. of this preamble, the population of existing units that would be subject to this proposed regulation has been expanded from the 2000 CISWI rule. The combustion survey Information Collection Request (ICR) responses show that our population of 176 CISWI units now includes combustion units with various fundamental differences in relation to units that were regulated as CISWI in the 2000 CISWI rule. We are proposing to subcategorize CISWI units based on technical and other differences in the processes, such as combustor design, draft type and availability of utilities. These proposed subcategories for CISWI have been established based on fundamental differences in the types and sizes of units that will be subject to the standards.

Incinerators:

Incinerators, which are the units currently regulated by the 2000 CISWI rule, are used to dispose of solid waste materials, and emissions are a function of the types of materials burned. Incinerators are designed without integral heat recovery (but may include waste heat recovery). While there are different designs, they all serve the same purpose: Reduction in the volume of solid waste materials. Incinerators can be operated on a batch or continuous basis. The same types of add-on controls, including fabric filters, wet scrubbers, SNCR and activated carbon injection, can be applied to most incinerators. Although the composition of the materials combusted is highly variable and is a key factor in the profile of emissions, we determined it was not appropriate to further subcategorize incinerators because the sources in this category are sufficiently similar such that the incinerators can achieve the same level of performance for the nine regulated pollutants.

Energy-recovery units:

Energy recovery units combust solid waste materials as a percentage of their fuel mixture and are designed to recover thermal energy in the form of steam or hot water. Energy recovery units include units that would be considered boilers and process heaters if they did not combust solid waste. Energy recovery units are generally larger than incinerators. They typically fire a mixture of solid waste and other fuels, whereas incinerators burn predominantly solid waste, although sometimes a small amount of supplemental fuel is fired in an incinerator to maintain combustion temperature. Energy recovery units are also different from incinerators in terms of how the fuel is fed into the combustion chamber, the combustion chamber design (which typically includes integral heat recovery) and other operational characteristics. These differences can result in emission profiles for energy recovery units that are different from incinerators but similar to boilers. Combustion of waste materials in these units impacts the emission profile to some degree, although emissions from these units often resemble emissions from boilers that combust traditional fuels.

Waste-burning kilns:

Waste-burning kilns are fundamentally different than any other unit being regulated under CISWI. Kilns of all types are physically larger than an incinerator with a comparable heat input. Kiln design and operation are also different. For example, the design is typically a rotating cylindrical kiln with a fuel burner on one end and raw materials being fed in the other (cold) end. Fuel (particularly solids such as tires) may also in some cases be fed at a mid-kiln point. Some kilns also have a large preheater tower with a precalciner that is an additional firing point for both fossil and waste fuels. The temperature profile of kilns is critical in order to produce a saleable product. Another key distinction is that for cement kilns, the source of most of the pollutants is typically the raw materials, not the fuels, and emissions from the raw materials and the solid wastes and fuels are comingled and emitted together. As a result, waste-burning kilns have a very different emissions profile than other CISWI subcategories and that difference can influence the design of applicable controls.

Burn-off ovens:

These units typically are very small (<1 MMBtu/hr), batch-operated, combustion units that are used to clean residual materials off of various metal parts, which are then reused. The amount of waste combusted in these units is generally small (pounds per year in some cases) and the configuration of the stacks that serve these units precludes the use of some EPA test methods for measuring emissions and could affect the ability to install certain control devices.

Small, remote, incinerators:

These are batch-operated units that combust less than one ton of waste per day and are farther than 50 miles driving distance to the closest MSW landfill. To the extent that these are located in Alaska, a major difference in these types of units is the inability to operate a wet scrubber in the northern climates and the lack of availability of wastewater handling and treatment utilities. We believe this would impact their ability to meet emission limits for pollutants controlled by wet scrubbers. In addition, because of the remote location, these units do not have lower-cost alternative waste disposal options (

i.e.,

landfills) nearby and emissions associated with transporting the solid waste could be significant.

C. Rationale for MACT Floor Emission Limits

EPA must consider available emissions test data to determine the MACT floor. We based the floor calculations on available emissions data.

We did receive some additional data earlier this year, but as noted above, due to the court-ordered

deadline, we did not have sufficient time to review and evaluate that data. We intend to review and evaluate the data submitted earlier this year and any data received during the comment period, and we intend to include those data in our final analysis, as appropriate.

In calculating the floors for this proposed rule, we included units combusting manure.

For existing sources, we calculated the MACT floor for each subcategory of sources by ranking the emission test results from units within the subcategory from lowest emissions to highest emissions (for each pollutant) and then taking the numerical average of the test results from the best performing (lowest emitting) 12 percent of sources. That is, the overall 3-run test average values for each existing unit for each pollutant were compiled and ranked from lowest to highest to identify the best performing 12 percent of sources within the subcategory for each pollutant (

i.e.,

on a pollutant-by-pollutant basis).

Because the number of units in different subcategories may be different, the number of units that represent the best performing 12 percent of different subcategories may be different. Also, mathematically, the number of units that represent the best performing 12 percent of the units in a subcategory will not always be an integer. To ensure that each MACT standard is based on at least 12 percent of the units in a subcategory, EPA has determined that it is appropriate to always round up to the nearest integer when 12 percent of a given subcategory is not an integer. For example, if 12 percent of a subcategory is 4.1, the standards will be based on the best performing five units even though rounding conventions would normally lead to rounding down to four units. Another example from this proposal is in the incinerator subcategory, which includes 28 units. Twelve percent of 28 is 3.36 units and we established the standards based on the best performing four units.

The pollutant-by-pollutant approach is the same approach used for other CAA Section 129 standards and the rationale for this approach can be found in the preamble for the final HMIWI NSPS and EG (74 FR 51368, 51380 (October 6, 2009)).

Once the best 12 percent of units are identified for each source category and pollutant, the individual test run data for these units were compiled and a statistical analysis was conducted to calculate the average and account for variability and, thereby, determine the MACT floor emission limit. The first step in the statistical analysis includes a determination of whether the data used for each MACT floor calculation were normally or log-normally distributed, followed by calculation of the average and 99th percent upper limit (UL).

If the data were normally distributed (

e.g.,

similar to a typical bell curve), then the equation to calculate UL was applied to the data. If the data were not normally distributed (for example if the data were asymmetric or skewed to the right or left), then the type of distribution (

e.g.,

log-normal) was determined and a data transformation was performed to normalize the data prior to computing the UL. When the data distribution was found to be log-normal, the data were transformed by taking the natural log of the data prior to calculating the UL value. Two statistical measures, skewness and kurtosis, were examined to determine if the data were normally or log-normally distributed. Additional discussion of the distribution analysis and the data distributions used to develop each MACT floor limit are documented in the memorandum “MACT Floor Analysis for the Industrial and Commercial Solid Waste Incinerators Source Category” in the docket.

The procedure is the same as used for the HMIWI rule (74 FR 51367, October 6, 2009). While the HMIWI preamble referred to this measure as the upper confidence limit (UCL), it used the same equation. In this proposal, we refer to the measure as the UL, which is a more appropriate statistical terminology for this calculation.

The 99th percent UL represents a value that 99 percent of the data in the MACT floor data population would fall below, and therefore, accounts for the run-to-run and test-to-test variability observed in the MACT floor data set. It was calculated by the following equation that is appropriate for small data sets:

UL = x + t(0.99,n) * s

Where:

x = average of the data.

t(0.99,n) = t-statistic.

n = number of data points in the population.

s = standard deviation.

A detailed discussion of the MACT floor methodology is presented in the memorandum “MACT Floor Analysis for the Industrial and Commercial Solid Waste Incinerators Source Category” in the docket. The calculated existing source UL values (which are based on the emissions data from the best performing 12 percent of sources and account for variability) were selected as the proposed MACT floor emission limits for the nine regulated pollutants in each subcategory. In establishing the limits, the UL values were rounded up to two significant figures. For example, a value of 1.42 would be rounded to 1.5 (as has been done for other CAA Section 129 rules) because a limit of 1.4 would be lower than the calculated MACT floor value.

The UL computation assumes that the data available represents the entire population of data from the best performing CISWI units used to establish the proposed standards. This statistical approach and use of the UL is consistent with the methodology used in the October 6, 2009, HMIWI rule (74 FR 51368).

The summary results of the UL analysis and the MACT floor emission limits for existing units are presented in Tables 4 through 6 of this preamble for each subcategory.

Table 4—Summary of MACT Floor Results for Existing Units—PM, Hg, Cd and Pb

Subcategory

Parameter

(mg/dscm)

Pb (mg/dscm)

Incinerators

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

4.01

0.000359

0.000362

0.00125

99% UL of top% (test runs) =

12.76

0.00278

0.00124

0.00258

Proposed Limit =

0.0028

0.0013

0.0026

Energy recovery units

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

4.249

0.000053

0.000157

0.000967

99% UL of top% (test runs) =

9.179

0.000960

0.000409

0.00197

Proposed Limit =

9.2

0.00096

0.00041

0.002

Waste-burning kilns

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

5.36

0.003649

0.000112

0.00105

99% UL of top% (test runs) =

59.97

0.0240

0.000293

0.00261

Proposed Limit =

0.024

0.0003

0.0027

Burn-off ovens

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

9.25

0.00267

0.00123

0.0125

99% UL of top% (test runs) =

32.14

0.0135

0.00448

0.0408

Proposed Limit =

0.014

0.0045

0.041

Small, remote incinerators

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

102.93

0.0017

0.0589

0.5627

99% UL of top% (test runs) =

238.85

0.00289

0.256

1.4012

Proposed Limit =

240

0.0029

0.26

1.4

Table 5—Summary of MACT Floor Results for Existing Units—HC

, NO

and SO

Subcategory

Parameter

HCl

(ppmdv)

Incinerators

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

0.1812

14.7

0.73

99% UL of top% (test runs) =

28.05

33.09

2.48

Proposed Limit =

2.5

Energy recovery units

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

0.2415

64.24

1.67

99% UL of top% (test runs) =

1.42

124.55

4.01

Proposed Limit =

1.5

130

4.1

Waste-burning kilns

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

0.5503

525.24

34.05

99% UL of top% (test runs) =

1.435

1,080.3

409.67

Proposed Limit =

1.5

1,100

410

Burn-off ovens

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

27.10

51.63

0.88

99% UL of top% (test runs) =

124.8

110.23

10.48

Proposed Limit =

130

120

Small, remote incinerators

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

66.5

91.83

12.18

99% UL of top% (test runs) =

143.7

207

43.35

Proposed Limit =

150

210

Table 6—Summary of MACT Floor Results for Existing Units—CO and Dioxin/Furans

Subcategory

Parameter

(ppmdv)

Dioxin/Furan (total mass basis)

(ng/dscm)

Dioxin/Furan (total TEQ basis)

(ng/dscm)

Incinerators

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

0.860

0.0113

0.55877

99% UL of top% (test runs) =

2.17

0.0304

27.75

Proposed Limit =

2.2

0.031

0.0025

Energy recovery units

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

39.096

0.09824

9.8831

99% UL of top% (test runs) =

146.8

0.748

7431.9

Proposed Limit =

150

0.75

0.059

Waste-burning kilns

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

147.33

0.02958

0.000935

99% UL of top% (test runs) =

701.18

2.03

7,959

Proposed Limit =

710

2.1

0.17

Burn-off ovens

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

28.58

0.0455

99% UL of top% (test runs) =

79.36

303.8

Proposed Limit =

310

Small, remote incinerators

No. of sources in subcategory =

No. in MACT floor =

Avg of top 12%

17.42

473.4

99% UL of top% (test runs) =

77.48

1,502

Proposed Limit =

1,600

130

—Dioxin/furan TEQ UL values often were greater than the total mass basis UL values, which would result in a TEQ limit greater than the total mass basis. Therefore, paired total mass basis/TEQ data were analyzed and found that TEQ is 0.078 times the amount of the total mass basis. The dioxin/furan TEQ limits were therefore calculated based on 0.078 times the total mass basis limit.

—Dioxin/furan TEQ data were not reported for this subcategory.

Using the UL approach described above for the dioxins/furans TEQ data sometimes resulted in a UL that was greater than that calculated for the associated total mass basis dioxins/furans for the subcategory, due to comparatively large standard deviations of the TEQ data versus those of the total mass basis data set. Dioxins/furans TEQ values should correlate to the total mass basis value at a ratio of less than 1 (a 1-to-1 ratio is the theoretical maximum and would indicate that all the dioxins/furans emitted would consist of the 2,3,7,8-tetrachlorodibenzodioxin (TCDD) congener). We reviewed available data to see what the ratio was for test reports where the total mass and TEQ data were simultaneously reported. Because it is impossible for the same concentration data to be higher on a TEQ basis than a total mass basis, TEQ to total mass basis ratios greater than 1 were omitted. Ratios greater than 0.5 were also screened out of the paired data because EPA is unaware of any combustion units ever having a TEQ to total mass basis ratio as high as 0.5. After screening the paired data, the resulting ratios were on average 0.078 times that of the total mass basis. Therefore, to be consistent in establishing the dioxins/furans TEQ limits and to prevent any instances where the TEQ limit exceeds the associated total mass basis limit, we selected MACT floor limits based on the total mass basis limit multiplied by 0.078. EPA requests comment on this approach for establishing the dioxins/furans TEQ basis limits.

New source MACT floors are based on the best performing single source for each regulated pollutant, with an appropriate accounting for emissions variability. In other words, the best performing unit was identified by ranking the units from lowest to highest for each subcategory and pollutant and selecting the unit with the lowest 3-run test average emission test data for each pollutant. The UL was determined for the individual 3-run test run data set for the best performing source for each regulated pollutant. Tables 7 through 9 of this preamble present the analysis summaries and the new source MACT floor limits.

Table 7—Summary of MACT Floor Results for Particulate Matter and Metals for New Sources

Subcategory

Parameter

(mg/dscm)

Incinerators

Avg of top performer

0.0056

0.0001

0.0002

0.0007

99% UL of top (test runs) =

0.00766

0.000123

0.000654

0.00126

Proposed limit =

0.0077

0.00013

0.00066

0.0013

Energy recovery units

Avg of top performer

3.270

0.000032

0.000085

0.000454

99% UL of top (test runs) =

4.37

0.00013

0.000115

0.001189

Proposed limit =

4.4

0.00013

0.00012

0.0012

Waste-burning kilns

Avg of top performer

0.9287

0.00101

0.000038

0.000386

99% UL of top (test runs) =

1.80

0.00077

Proposed limit =

1.8

0.024

0.0003

0.00078

Burn-off ovens

Avg of top performer

6.676

0.0007

0.0008

0.0050

99% UL of top (test runs) =

27.48

0.00329

0.00316

0.02859

Proposed limit =

0.0033

0.0032

0.029

Small, remote incinerators

Avg of top performer

83.53

0.001

0.011

0.448

99% UL of top (test runs) =

268.9

0.00126

0.0564

1.3877

Proposed limit =

240

0.0013

0.057

1.4

—Only one run data point, therefore UL cannot be calculated. The EG limit was selected as the NSPS limit.

—The NSPS UL limit exceeds the EG limit. The EG limit was selected as the NSPS limit.

Table 8—Summary of MACT Floor Results for New Units—HC

, NO

, SO

Subcategory

Parameter

(ppmdv)

Incinerators

Avg of top performer

0.0413

9.033

0.223

99% UL of top (test runs) =

0.0732

18.99

1.47

Proposed limit =

0.074

1.5

Energy recovery units

Avg of top performer

0.06813

52.57

1.049

99% UL of top (test runs) =

0.169

74.52

4.44

Proposed limit =

0.17

4.1

Waste-burning kilns

Avg of top performer

0.13

108.3

1.43

99% UL of top (test runs) =

134.65

3.58

Proposed limit =

1.5

140

3.6

Burn-off ovens

Avg of top performer

7.106

13.16

0.000

99% UL of top (test runs) =

17.56

15.43

Proposed limit =

1.5

Small, remote incinerators

Avg of top performer

45.437

73.66

4.793

99% UL of top (test runs) =

244.01

367.23

42.49

Proposed limit =

150(a)

210

—The NSPS UL limit exceeds the EG limit. The EG limit was selected as the NSPS limit.

—Only one run data point, therefore UL cannot be calculated. The EG limit was selected as the NSPS limit.

—Zero value calculated for the subcategory, which will not allow for data variability. The lowest unit with non-zero data was used to calculate this limit.

Table 9—Summary of MACT Floor Results for New Units—CO and Dioxins/Furans

Subcategory

Parameter

(ppmdv)

Dioxin/Furan (Total mass basis)

(ng/dscm)

Dioxin/Furan (Total TEQ basis)

(ng/dscm)

Incinerators

Avg of top performer

0.600

0.0023

0.0102

99% UL of top (test runs) =

1.39

0.00927

0.035

Proposed limit =

1.4

0.0093

0.00073

Energy recovery units

Avg of top performer

0.650

0.0161

0.0005

99% UL of top (test runs) =

2.95

0.0334

0.00181

Proposed limit =

3.0

0.034

0.0027

Waste-burning kilns

Avg of top performer

16.22

0.00011

0.000000

99% UL of top (test runs) =

35.23

0.000348

0.000000

Proposed limit =

0.00035

0.000028

Burn-off ovens

Avg of top performer

17.51

0.0013

99% UL of top (test runs) =

73.87

0.0101

Proposed limit =

0.011

0.00086

Small, remote incinerators

Avg of top performer

0.447

366.3

99% UL of top (test runs) =

3.96

1,103.3

Proposed limit =

4.0

1,200

—Dioxin/furan TEQ data were not reported for this subcategory.

As noted in the tables above, there were some instances where there were fewer test runs available for the best performing unit so that the UL could not be calculated. There were also some cases where the calculated UL produced a result that was greater than the existing MACT floor limit for that pollutant in that subcategory. Since the limit for new sources cannot be less stringent than that of existing sources, EPA selected the existing source MACT floor limit as the new source MACT floor limit in these instances. There was also one case where the best-performing source in the burn-off oven subcategory reported zero for each test run for SO

. This yields a calculated UL of zero (since the mean and standard deviation are zero), which does not give any allowance for variability. To address this, EPA used test data for the next best-performing source (

i.e.,

the lowest emitting source with non-zero test data). EPA solicits comment on this approach for setting this limit.

EPA also solicits comment on whether the EPA should use an alternate one-sided statistical interval, the 99 percent UPL instead of the UL. In general, a prediction interval (

e.g.,

a UPL) is useful in determining what future values are likely to be, based upon present or past background samples taken. The 99 percent UPL represents the value which one can expect the mean of future 3-run performance tests from the best-performing 12 percent of sources to fall below with 99 percent confidence, based upon the results of the independent sample of observations from the same best performing sources. The 99 percent UPL value based on the test run data for those units in the best-performing 12 percent can be calculated using one of the following spreadsheet equations depending on the distribution of the data:

Normal distribution: 99% UPL = AVERAGE(Test Runs in Top 12%) + [STDEV(Test Runs in Top 12%) × TINV(2 × probability, n−1 degrees of freedom) × SQRT((1/n) + (1/m))], for a one-tailed upper prediction limit with a probability of 0.01, sample size of n, and number of test runs whose average will be reported to EPA for compliance of m = 3.

Lognormal distribution: 99% UPL = EXP {AVERAGE(Natural Log Values of Test Runs in Top 12%) + [STDEV(Natural Log Values of Test Runs in Top 12%) × TINV(2 × probability, n−1 degrees of freedom) × SQRT((1/n) + (1/m))]}, for a one-tailed upper prediction limit with a probability of 0.01, sample size of n, and number of test runs whose average will be reported to EPA for compliance of m = 3.

In addition to the nine regulated pollutants, EPA is also proposing opacity standards for new and existing

CISWI. We considered how to appropriately account for variability, given the differences in opacity testing versus testing for the nine regulated pollutants. Because opacity can be affected by the amount, type and particle characteristics of PM in the gas stream, as well as process operation, we believe that opacity is an appropriate surrogate for PM emissions. Therefore, using a ratio of PM to opacity would be an appropriate method for determining the opacity that would be associated with a given PM concentration. Using the data available for CISWI units, we identified the best-performing unit with respect to PM for which we have opacity data, and that unit has a ratio of opacity to PM of 0.053. This ratio was then multiplied by each of the MACT floor PM limits, which were determined accounting for variability, for each subcategory to establish an opacity limit. We are requesting comment on whether this is a reasonable approach to establishing opacity limits while accounting for data variability, and request any additional opacity information that we may utilize to establish an opacity limit. We are also requesting comment on the appropriateness of setting opacity limits for this source category.

As explained above, concurrent with this proposal, EPA is also proposing to define the term “solid waste” for non-hazardous secondary materials. That proposal describes two alternative definitions of solid waste, and EPA has in this proposed rule for CISWI units calculated MACT standards based on each solid waste definition. EPA is proposing MACT emissions standards based on the primary proposed definition of solid waste. In addition, EPA has determined the MACT emissions standards that would apply if the alternative proposed definition of solid waste was finalized, and we are taking comment on those standards.

For purposes of the MACT standards based on the primary proposed definition of solid waste, we have considered certain secondary materials (including pulp and paper sludge, wood residuals, and some tire-derived fuel) not to be solid waste, based on available information. Therefore, units combusting those materials have not been included in the proposed CISWI MACT calculations (

i.e.,

the calculations based on the primary proposed definition of solid waste). EPA solicits comment on that conclusion for these and other secondary materials, and will take into account any relevant information that may warrant revising the proposed CISWI MACT floors. Comments relating to the proposed definition of solid waste should be submitted to the EPA docket for that rulemaking, because EPA will not be addressing any such comments in the final CISWI rule.

D. Rationale for Beyond-the-Floor Alternatives

As discussed above, EPA may adopt emissions limitations and requirements that are more stringent than the MACT floor (

i.e.,

beyond-the-floor). Unlike the MACT floor methodology, EPA must consider costs, non-air quality health and environmental impacts and energy requirement when considering beyond-the-floor alternatives.

In developing this proposal, EPA considered for existing units the proposed CISWI NSPS emission limits as a basis for the beyond-the-floor analysis for each subcategory. The CISWI NSPS limits are the MACT limits applicable to new CISWI units that are established through analysis of the best performing single source for each regulated pollutant (

see

earlier discussion in Section IV.C above). There are separate NSPS limits for each of the five CISWI subcategories: Incinerators; energy recovery units; waste-burning kilns; burn-off ovens; and small, remote incinerators. We request public comments on all aspects of the beyond-the-floor analysis, including whether there are combinations of control approaches that would cost-effectively reduce emissions of the Section 129(a)(4) pollutants. We specifically request that the commenter provide cost, technical and other relevant information in support of any beyond-the-floor alternatives. EPA will evaluate the comments and any other additional information and may adopt beyond-the-floor options for the final rule if any that are identified are determined to be reasonable.

The beyond-the-floor analysis for each subcategory is based on an evaluation of the types of control approaches that would be necessary to achieve the NSPS level of control for the same subcategory. Specifically, for purposes of our beyond-the-floor analysis, we evaluated the different combinations of available emission control techniques, including additional add-on controls, that existing units would have to employ were we to require additional emissions reductions beyond the floor levels set forth above. We are unaware of any control approaches other than those discussed below that would result in emissions reductions from CISWI units.

As part of our impacts analysis (discussed in section V. below), we evaluated whether existing facilities would choose to cease burning solid waste in incineration units after promulgation of the final CISWI standards. We have determined that most facilities with units in the incinerators, small remote incinerators or burn-off ovens subcategories will choose to cease operations once the proposed MACT floor limits are promulgated and that all units in these three subcategories will cease combusting waste if beyond-the-floor levels are adopted. We considered this fact in evaluating the beyond-the-floor options for these three subcategories and specifically in our consideration of the costs associated with the beyond-the-floor options, which we found unreasonable.

We analyzed the beyond-the-floor options on a pollutant-by-pollutant basis for each subcategory. We discuss below the possible beyond-the-floor controls and why we rejected them.

• For PM, Cd and Pb, units would add a fabric filter if there were none already, or improve the fabric filter if the unit is already equipped with one but could not meet the beyond-the-floor limit. Units could also be required to add an additional PM control device if existing fabric filters could not be modified to comply with the beyond-the-floor limit.

• For HCl and SO

, units would add a packed-bed wet scrubber if there were none already, or if a wet scrubber already existed on the unit, upgrade to a larger pump to increase the liquid to gas ratio. If the unit was equipped with lime injection or a spray dryer, the beyond-the-floor technology was to add more lime for SO

control. If more control was needed for SO

, but not HCl, and the unit has a wet scrubber already, they would add caustic to the scrubber liquor. Units could also be required to add an additional SO

control device if the existing scrubber could not be modified to comply with the beyond-the-floor limit. The floor limits established above for waste-burning kilns are already at the quantification limits of the test method and we are not aware of alternative methods to quantify additional reductions in HCl emissions. In addition, we are not aware of any control technologies available that would reduce HCl emission from existing waste-burning kilns to levels below the floor levels. Therefore, we could not evaluate a beyond-the-floor option for HCl emissions from waste-burning kilns.

• For Hg and CDD/CDF, activated carbon would be added and the carbon addition rate would be adjusted to meet

the amount of reduction necessary to meet the proposed limit.

• For NO

, no beyond-the-floor options are demonstrated to be achievable, as discussed below.

• For CO, the beyond-the-floor option consists of afterburner retrofits, tune-ups, advanced combustion controls or catalytic oxidation for each subcategory except for waste-burning kilns and energy recovery units. No beyond-the-floor options are available for these two subcategories, as discussed below.

CO.

For CO, we evaluated afterburner retrofits, tune-ups, advanced combustion controls or an oxidation catalyst for incinerators, small remote incinerators and burn-off ovens as being potential beyond-the-floor control technologies that could be applied to these units. Afterburner retrofits are applicable to units that have a secondary combustion chamber or an afterburner chamber installed on the device. Waste-burning kilns and energy recovery units are not designed with secondary chambers or afterburners, so this particular control cannot be applied to these two subcategories.

For waste burning kilns, a significant amount of CO emissions can result from the presence of organic compounds in the raw materials and not only from incomplete combustion, so good combustion controls and practices are not as effective. Oxidation catalysts have not been applied to waste-burning kilns and may not be as effective on waste-burning kilns as they are on other sources due to plugging problems. The only effective beyond-the-floor control we could identify for waste-burning kilns would be a regenerative thermal oxidizer (RTO). In the analysis for the proposed Portland Cement NESHAP, EPA notes that the additional costs and energy requirements associated with an RTO are significant, with an additional annualized cost of $3.8 million per year (

see

74 FR 21153). Under the most cost effective scenario (existing unit emitting at 710 ppmv and a 98 percent CO reduction) the cost per ton of additional CO removal would be approximately $1,500. However, at the CO levels for most facilities, the cost per ton could be much higher. In addition, RTO have significant additional energy requirements, and themselves create secondary emissions of CO, NO

and PM due to their electrical demands (see 74 FR 21153). Given the cost and adverse environmental and energy impacts, we determined that RTO was not a reasonable beyond-the-floor alternative to control CO emissions from waste-burning kilns.

For energy recovery units, we analyzed a beyond-the-floor CO limit of 3 ppm. In comparison, the proposed MACT floor emission limit is 150 ppm. Therefore, the beyond-the-floor CO emission limit is approximately 98 percent less than the MACT floor emission limit. We are unaware of any technology that is able to continuously meet a 3 ppm CO limit for all existing energy recovery units. Variances in fuel composition and condition will have an effect on CO emissions in addition to the controls in place, so this limit may be achievable for the best source based on their particular unit design and fuel inputs, but not demonstrated to be achievable for any other existing units without unreasonable costs associated with modification of the units. As a comparison, the proposed boiler NESHAP limit varies by combustor design, but for biomass boilers, which burn fuels and have combustor designs that are similar in characteristics to some CISWI energy recovery units, the limits are in the order of 200 to 700 ppm. Given the lack of available controls that are demonstrated to achieve the beyond-the-floor emission limits at existing units and the costs associated with making the necessary modifications at existing units, we are not proposing beyond-the-floor limits for CO for energy recovery units.

. For NO

, we evaluated SNCR as the likely control technology that sources would apply to achieve the beyond-the-floor limits. The control option would be to add SNCR if there were none installed to meet the MACT floor, or to increase the reagent injection rate if the unit was already equipped with SNCR technology. We also considered whether selective catalytic reduction (SCR) could be utilized by sources to achieve the beyond-the-floor limits. SNCR is a proven technology for waste-combustion units, with typical effectiveness of 30 to 50 percent. These reductions are within the reach of the levels estimated to meet the MACT floor emission limits. However, to achieve lower reductions (

i.e.,

greater than 50 percent) than the beyond-the-floor limits would require, SNCR may need to be applied in conjunction with combustion controls (Air Pollution Control Technology Fact Sheet, SNCR, EPA-452/F-03-031). Feasibility of these combustion controls, such as low NO

burners or combustion chamber modifications, are unit-specific and are likely not applicable to all existing units; therefore, compliance with the beyond-the-floor would likely require significant modification at considerable cost for some existing units. In contrast, new sources can be designed so that the combustion chamber and air flow characteristics reduce NO

formation, which, in combination with SNCR controls, would be able to meet the new source NO

limits. SCR is typically utilized in combustion units such as industrial boilers and process heaters, gas turbines and reciprocating internal combustion engines (Air Pollution Control Technology Fact Sheet, SCR, EPA-452/F-03-032). We are not aware of any successful applications of SCR technology to waste-combustion units, however. This may be due to difficulties operating SCRs in operations where there is significant PM or sulfur loading in the gas stream. These two gas stream constituents can reduce catalyst activity, and lower the resulting effectiveness of the SCR, through catalyst poisoning and blinding/plugging of active sites by ammonia sulfur salts (formed from sulfur in the flue gas with the ammonia reagent) and PM (Air Pollution Control Technology Fact Sheet, SCR, EPA-452/F-03-032). Therefore, we determined that available controls were not demonstrated adequately for existing CISWI units in any of the five subcategories to meet the beyond-the-floor NO

emission limits.

HCl and SO

. We expect that waste-burning kilns would install scrubbers to meet the proposed MACT floor emission limits for HCl, and the proposed EG and NSPS limits for HCl are the same. As discussed above, the HCl floor level for waste-burning kilns is near the quantification limits of the available test methods, and we are not aware of alternative methods to quantify beyond-the-floor reductions.

The scrubbers needed to meet the CISWI MACT floor limits for HCl would also meet the CISWI MACT floor levels for SO

. However, we are not certain that it is feasible for existing waste-burning kilns to utilize additional caustic in their scrubbers, or in their existing flue gas desulfurization devices, to be able to consistently meet the 3.6 ppm beyond-the-floor emission limit for SO

. There are limits to the amounts of additional caustic or lime that are technically feasible and the SO

content of the flue gas will vary depending on the fuel and the sulfur content of process raw materials that are charged to the waste-burning kiln. The only option for achieving additional SO

control is to add an additional SO

scrubbing device in series with the scrubber required to comply with the MACT floor limit. While we did not quantify the costs, we concluded, based on our review of the cost information, that this level of control would pose unreasonable costs that would result in units ceasing to combust wastes in kilns. Therefore, we determined that

additional controls were not demonstrated to continuously meet the beyond-the-floor SO

emission limits at existing waste-burning kilns. We examined beyond-the-floor options for the other subcategories as discussed below.

PM.

In our analysis, we estimate that waste-burning kilns would install fabric filter controls or improve existing fabric filters to meet the proposed CISWI MACT floor limits for PM and metals. To meet the metals floor limits, highly efficient fabric filters, and possibly membrane bags, would be needed. These controls are the best technology available to control PM, and we have not identified any additional controls that are available that would enable existing waste-burning kilns to continuously meet the beyond-the-floor PM emission limit equivalent to the proposed CISWI NSPS limit (which is considerably lower than the CISWI floor). We analyzed beyond-the-floor controls for the other four subcategories as discussed below.

As with waste-burning kilns, we estimate that existing units in the energy recovery units subcategory would install fabric filter controls or improve existing fabric filters to meet the proposed CISWI MACT floor limits for PM and metals. As with waste-burning kilns, the fabric filters would need to be highly efficient to meet the metals floor limits, and likely would need to be membrane bags. As stated above, membrane fabric filters are the best technology available to control PM and metals. As such, the fabric filters that we believe will be necessary to control the metals will likely achieve a level of performance that is better than the MACT floor limit for PM, resulting in additional PM reductions beyond the existing source floor level of control. For this reason, we believe that the PM emissions reductions associated with going beyond-the-floor to the new source floor limits is less than the 200 tons per year estimated based on an evaluation of the difference in PM emissions under the proposed existing source floor and the proposed new source floor. Furthermore, to achieve PM and metals emissions reductions greater than those achieved using the fabric filters that will be required to meet the MACT floor emission limits, existing sources would likely need to install an additional particulate control device, such as a cartridge filtration system, which would require additional capital and operating expense, as well as require additional energy to power the fans for adequate draft. While we did not quantify the costs, we concluded, based on our review of the cost information, that this level of control would pose unreasonable costs.

We analyzed beyond-the-floor controls for the other three subcategories as discussed below.

Emissions Reduction Analysis Results.

We analyzed the emissions reductions that would be achieved if the beyond-the-floor levels were adopted as MACT for those pollutants and subcategories for which additional control techniques were identified that could achieve beyond-the-floor emission limits. We estimate that the beyond-the-floor levels for existing CISWI units would achieve additional emission reductions (relative to the MACT floor) of 326 tons per year (0.01 tons Cd, 3.5 CO, 113 HCl, 0.07 Pb, 0.03 Hg, −0.1 NO

208 PM, 1.6 SO

and 0.0001 dioxins/furans).

Analysis Results for Incinerator, Small Remote Incinerator and Burn-Off Ovens Subcategories

As was done in the cost analysis for the MACT floor emission limits, we also considered whether units would cease to combust waste and choose an alternative waste disposal method rather than add controls to comply with the beyond-the-floor limits. Based on the high costs of controls relative to the costs of alternative waste disposal methods, we concluded that all units within the incinerators, burn-off ovens and small remote incinerators subcategories would shut down rather than comply with the beyond-the-floor limits. Facilities with incinerator units and small remote incinerator units would use alternative landfill disposal and facilities with burn-off ovens would use abrasive blasting. In comparison, for the MACT floor impacts analysis, we determined there were 17 total units within these three subcategories that would remain open and comply with the MACT floor emission limits. The emission reductions above account for the secondary impacts of landfill gas flare emissions that would result from the incremental waste that is diverted to landfills from existing CISWI units. Once these secondary impacts of the landfill gas flaring are accounted for, the emissions reduction is approximately zero for the incinerator, small remote incinerator and burn-off oven subcategories, mainly due to the increase in emissions from flaring the landfill gases generated by the additional diverted waste, compared to the modest additional stack emissions reductions from shutting these units down.

The cost of the additional emissions reductions associated with going from the MACT floor to the beyond-the-floor level vary by pollutant and subcategory. For the incinerator, small remote incinerator and burn-off oven subcategories, the incremental annualized costs of control or alternative waste disposal is approximately $690,000. As mentioned above, because of the increase in landfill gases, this additional cost would result in no additional emissions reductions for these source categories. The beyond-the-floor limits for these source categories would be achieved at considerable cost, would result in closure of additional units that would not close under the floor alternative, and would result in no additional emissions reduction; therefore, we have determined it is not reasonable to go beyond-the-floor for these source categories.

Analysis Results for Energy Recovery Units and Waste-Burning Kilns.

For the energy recovery units and waste-burning kilns, we analyzed the additional emissions reductions and additional control and monitoring costs of going beyond-the-floor by pollutant groups according to the controls described above. Table 10 of this preamble lists the incremental costs and pollutant emissions reductions relative to the MACT floor level of control.

Table 10—Incremental Costs and Emission Reductions Expected for Existing Units To Comply With Beyond-the-Floor Emission Limits (Relative to the MACT Floor)

Pollutants

Subcategory

Additional

annual costs

($/yr)

Additional

emissions

reductions

(ton/year)

Incremental cost effectiveness

(additional costs/additional emissions reductions, $/ton)

PM, Cd, Pb

Energy recovery unit

2,082,013

202

10,307

Hg, CDD/CDF

Energy recovery unit

18,562,287

0.03

618,742,900

Waste-burning kiln

126,944,291

0.00002

>1 Billion

HCl, SO

Energy recovery unit

15,985,182

207,599

As discussed earlier, we believe that the additional emissions reduction for PM, Cd, and Pb are likely to be much lower than this analysis suggests, because sources will require some of the best PM control devices to meet the MACT floor level of control for metals, and will likely exceed the level of performance for PM needed to meet the MACT floor emission limit. Therefore, we have concluded that the incremental costs of additional control above the MACT floor emission limits are not reasonable relative to the level of emission reduction achieved.

New Units.

No beyond-the-floor option was analyzed for new units because we are not aware of any technologies or methods to achieve emission limits more stringent than the MACT floor limits for new units. As an example, we have discussed potential problems associated with additional SNCR reagent earlier in this section of the preamble. Incremental additions of activated carbon have not been proven to achieve further reductions above the projected flue gas concentration estimated to achieve the limits for new sources. Furthermore, we already estimate no new CISWI sources will be constructed due to the costs associated with the MACT floor limits in the proposed NSPS. For this reason, we do not think it is reasonable to further add to the costs associated with the proposed NSPS.

In light of the technical feasibility, costs, energy and non-air quality health and environmental impacts discussed above, we have determined it is not reasonable to establish beyond-the-floor limits for existing and new CISWI units.

We also calculated potential beyond-the-floor emissions reductions for the “alternative approach” identified for consideration and comment in a parallel proposal under RCRA, which could potentially result in an additional 13,014 tons per year of projected emissions reductions (0.9 Cd, 3.5 CO, 7 HCl, 16.4 Pb, 1.3 Hg, −0.1 NO

, 12,984 PM, 1.6 SO

and 0.001 dioxins/furans). These are the reductions that would be achieved if we adopted the NSPS limits for the alternative approach as the beyond-the-floor limit for existing sources. We considered the same technical considerations and used the same emissions reductions and cost calculation methodologies described above for the proposed approach, which result in very similar cost effectiveness values as presented in Table 10 of this preamble. However, we note that several of the MACT floor limits for energy recovery units and waste-burning kilns under the alternative approach are not as stringent as those for the proposed approach, and the additional emission reductions that can be achieved by going beyond the floor for the alternative approach are much greater than the emission reductions available by going beyond the floor under the primary approach. Therefore, in the case of the alternative approach, there may be intermediate levels of control that would be reasonable. Additional information on floor and beyond-the-floor costs is discussed in “Compliance Cost Analyses for Existing CISWI Units” found in the CISWI docket.

E. Rationale for Other Proposed Amendments

In addition to the proposed emission limits, the following amendments are being proposed in this action.

1. Definitions and Removal of Exemptions

We are revising the definition of CISWI unit to reflect the Court decision that all units burning solid waste as defined by the Administrator under RCRA are to be covered by regulation under CAA Section 129. We are also adding a definition of “solid waste incineration unit” and we are removing the definition of “commercial and industrial waste.” We are also proposing definitions of the five subcategories of CISWI units that will be regulated under the proposed rules.

In the 2000 CISWI rule, there were 15 types of units that were exempted from regulation under CISWI. We are proposing to remove some of the exemptions contained in the 2000 CISWI rule and we are maintaining the statutory exemptions and the exemptions for units included in the scope of other CAA Section 129 standards as discussed below. We believe that the proposed rule is drafted in such a way to avoid the situation where a unit subject to standards under another Section 129(a)(1) standard, would also be subject to this rule. We request comment on the proposed exemptions that address units included in the scope of other CAA Section 129 standards.

To address the vacatur of the CISWI Definitions rule, EPA is proposing to regulate any combustion unit burning any solid waste, as that term is defined by the Administrator under RCRA, at a commercial or industrial facility. The 2000 CISWI rule specifically exempted six types of units that may be CISWI units under this proposed rule: agricultural waste incineration units; cyclonic barrel burners; burn-off ovens; cement kilns; chemical recovery units; and laboratory analysis units. These six types of units would be regulated under the revised proposed CISWI standards if they burn solid waste at a commercial or industrial facility.

The exemptions that would be retained in the proposed rule are either statutory exemptions provided under CAA Section 129, or are for waste combustion units regulated under other Section 129 NSPS or EG. In particular, CAA Section 129(g)(1) specifically exempts:

“* * * incinerators or other units required to have a permit under section 3005 of the Solid Waste Disposal Act. The term `solid waste incineration unit' does not include (A) materials recovery facilities (including primary and secondary smelters) which

combust waste for the primary purpose of recovering metals, (B) qualifying small power production facilities, as defined in section 3(17)(C) of the Federal Power Act (16 U.S.C. 769(17)(C)), or qualifying cogeneration facilities, as defined in section 3(18)(B) of the Federal Power Act (16 U.S.C. 796(18)(B)), which burn homogeneous waste (such as units which burn tires or used oil, but not including refuse-derived fuel) for the production of electric energy or in the case of qualifying cogeneration facilities which burn homogeneous waste for the production of electric energy and steam or forms of useful energy (such as heat) which are used for industrial, commercial, heating or cooling purposes * * *”

Therefore, the proposed CISWI rule retains exemptions for materials recovery facilities, qualifying small power production facilities, qualifying cogeneration facilities and hazardous waste combustors required to have a permit under Section 3005 of the Solid Waste Disposal Act.

EPA is also proposing to exempt from CISWI the waste combustion units that are currently included in the scope of another effective NSPS or EG or that EPA currently intends to regulate in an NSPS or EG. Those waste combustion units are: MWC units; medical waste incineration units; sewage treatment plants; sewage sludge incineration units; and OSWI units, which include pathological waste incineration units and institutional incinerators. There are existing standards for MWC units, medical waste combustion units and sewage treatment plants, but no standards are currently in place for pathological waste incineration units or SSI units. Regulations are currently being developed for SSI under proposed NSPS and EG of part 60. EPA also currently intends to regulate pathological waste incineration units in the revised “Other Solid Waste Incineration (OSWI)” standards under development. EPA's intent in the CISWI rule is to exclude units that are properly regulated as OSWI units. However, additional solid waste incineration units may exist that are OSWI units, which EPA has not identified in this proposed rule. EPA solicits comment on the scope of the proposed exemptions for units subject to CAA Section 129 standards.

We are also proposing the removal of the 2000 CISWI rule exemption for units burning greater than 30 percent MSW and with the capacity to burn less than 35 tons per day of MSW or refuse derived fuel. We are proposing to remove this exemption to ensure that any CISWI unit combusting any solid waste is subject to these standards. Therefore, commercial and industrial units that were previously exempt pursuant to this provision would be required to meet the emission limits and operating requirements of the proposed rule.

The 2000 CISWI rule also defined CISWI units such that industrial and commercial waste combustion units recovering energy (

e.g.

units that would be boilers and process heaters if they did not combust solid waste) were not subject to regulation as CISWI units. This definition is not consistent with the statute and, as discussed above, the definitions are being revised to address the CISWI Definitions Rule vacatur so that any unit at a commercial or industrial facility combusting any solid waste, as defined by the Administrator under RCRA, will be subject to the CISWI NSPS or EG. Therefore, the proposed definitions would no longer make a distinction between those units that recover energy and those units that do not recover energy. As discussed earlier, those energy recovery units that burn solid waste but were previously subject to the boilers rule are now CISWI units and are addressed under the energy recovery units subcategory.

Cement kilns and rack, part and drum reclamation units (

i.e.

burn-off ovens) were exempt from the 2000 CISWI standards and, as stated above, we are proposing to create subcategories for those units and subject them to this proposed rule in light of the CISWI Definitions Rule vacatur. We note that other Section 129 standards may contain an exemption for cement kilns. Those exemptions do not excuse waste burning kilns as defined in this proposed rule from compliance with the proposed CISWI standards. As those other Section 129 rules are amended, we will clarify that cement kilns that meet the proposed definition of waste-burning kiln are exempt from those standards because they are subject to the CISWI standards.

For one type of unit that is exempt by statute from the definition of solid waste incineration unit, air curtain incinerators combusting “clean wood”, we are requesting comment on the requirement for those units to obtain title V permits.

In addition, we are considering amending the exemption provisions at 40 CFR 60.2020 and 60.2555 to remove all references to units that are statutorily exempt from the definition of solid waste incineration unit. If we took such action, we would develop a new section to retain the notification requirements contained in those sections and applicable to such statutorily exempt units. We request comment on this proposed approach.

2. Performance Testing and Monitoring Requirements

We are proposing some adjustments to the performance testing and monitoring requirements that were promulgated in 2000. For existing CISWI units, we are proposing retaining the current performance testing and monitoring requirements of the rule and adding the following requirements:

• Annual inspections of scrubbers, fabric filters and other air pollution control devices that may be used to meet the emission limits.

• Annual visual emissions test of ash handling procedures (for all subcategories except waste-burning kilns).

• Control device parameter monitoring for activated carbon injection, electrostatic precipitators and SNCR controls.

• For energy recovery units: CO CEMS monitoring, continuous opacity monitoring (COMS) for units that are not equipped with wet scrubbers and PM CEMS for units greater than 250 MMBtu/hr capacity.

• For waste-burning kilns, Hg CEMS monitoring.

• Monitoring of bypass stack use if installed at an affected unit.

These proposed requirements were selected to provide additional assurance that sources continue to operate at the levels established during their initial performance test. For the waste-burning kiln and energy recovery unit subcategories, the proposed CEMS requirements are consistent with the CAA Section 112(d) standards proposed for their non-waste burning counterparts, but adjusted to reflect the pollutants subject to CAA Section 129 regulations. For example, the proposed Portland Cement NESHAP (74 FR 21136) requires monitoring of Hg with a Hg CEMS. Likewise, the energy recovery unit monitoring requirements are similar to the Boiler NESHAP being proposed concurrently with the CISWI proposal. In doing so, we are not only reflecting the improvements in monitoring technology and practices for these subcategories made since 2000, but are also providing consistency in monitoring, recordkeeping and reporting, where appropriate. Likewise, the visual emissions test of ash handling procedures and annual control device inspections have been adopted for HMIWI, another CAA Section 129 source category. HMIWI standards (74 FR 51367) contain these requirements to ensure that the ash, which may contain metals, is not emitted to the atmosphere through fugitive emissions and that control devices are maintained properly.

The large and small MWC standards also have similar fugitive ash monitoring requirements. We propose to require the fugitive ash monitoring provisions that are contained in the HMIWI and MWC rules.

The proposed amendments would allow sources to use the results of emissions tests conducted within the previous two years to demonstrate initial compliance with the revised emission limits as long as the sources certify that the previous test results are representative of current operations. Such tests must have been conducted using the test methods specified in the CISWI rules and must be the most recent tests performed on the unit. Those sources, whose previous emissions tests do not demonstrate compliance with one or more of the revised emission limits, would be required to conduct another emissions test for those pollutants. This allowance to use previous tests would minimize the burden to affected sources, especially since most sources performed recent emissions tests in support of the development of the CISWI standards (

i.e.,

the CISWI Phase 2 ICR) and sources subject to the 2000 CISWI EG already test for HCl, PM and opacity on an annual basis. We seek comment on the appropriateness of the use of previously conducted performance tests.

The proposed amendments also would allow for reduced testing of PM, HCl, and opacity as were allowed in the rule promulgated in 2000, but we are proposing amending these reduced testing allowances to provide a compliance margin of 75 percent of the standard to be able to qualify for testing for these pollutants once every three years. The reduced testing allowance and compliance margin provides flexibility and incentive to sources that operate well within the emissions standard, and to provide more timely follow-through, on assuring that sources that are marginally in compliance, will remain in compliance.

Additional requirements also are proposed for new CISWI. For new sources, we are proposing retaining the current requirements and adding the requirements for existing units as listed above, plus requiring CO CEMS for all subcategories of CISWI. These CEMS would be relatively simple to install for a new CISWI unit, and would help ensure that the sources are operated well using good combustion practices. Low CO levels are an indicator of complete combustion and that the unit is being operated in a manner that minimizes not only CO emissions, but also emissions of other pollutants.

We also are clarifying that the rule allows for the following optional CEMS use: CO CEMS, NO

CEMS, and SO

CEMS for existing sources; and NO

CEMS, SO

CEMS, PM CEMS, HCl CEMS, multi-metals CEMS, Hg CEMS, integrated sorbent trap Hg monitoring and integrated sorbent trap dioxin monitoring for existing and new sources. Some of the subcategories may have CO CEMS, NO

CEMS, or SO

CEMS already to meet other regulatory or permit requirements and we propose to would allow them to continue to use these monitors to demonstrate continuous compliance with the CISWI standards. The optional use of HCl CEMS, multi-metals CEMS, integrated sorbent trap Hg monitoring and integrated sorbent trap dioxin monitoring will be available on the date a final performance specification for these monitoring systems is published in the

Federal Register

or the date of approval of a site-specific monitoring plan. The proposed monitoring provisions are discussed in more detail below.

Monitoring Provisions for SNCR.

The proposed amendments would require monitoring of secondary chamber temperature (if applicable to the CISWI unit, since certain subcategories may not have a secondary chamber or afterburner) and reagent (

e.g.,

ammonia or urea) injection rate for CISWI that install SNCR as a method of reducing NO

emissions. These are easily measured parameters that will ensure the SNCR continues to be well operated and able to achieve the desired emissions reductions.

Monitoring Provisions for Activated Carbon Injection (Hg sorbent injection).

The proposed amendments would require monitoring of activated carbon sorbent injection rate to ensure that the minimum sorbent injection rate measured during the compliance test is continually maintained.

Monitoring Provisions for ESP.

The proposed amendments would require monitoring of the voltage and amperage of the collection plates to ensure that the ESP operating parameters measured during the compliance test are maintained on a continuous basis.

CO CEMS.

The proposed amendments would require the use of CO CEMS for new sources and allow the use of CO CEMS on existing sources, except energy recovery units, where a CO CEMS is also required for existing sources. Owners and operators who use CO CEMS would be able to discontinue their annual CO compliance test. The continuous monitoring of CO emissions is an effective way of ensuring that the combustion unit is operating properly. The proposed amendments incorporate the use of performance specification (PS)-4B (Specifications and Test Procedures for Carbon Monoxide and Oxygen Continuous Monitoring Systems in Stationary Sources) of appendix B of 40 CFR part 60.

The proposed CO emission limits are based on data from infrequent (normally annual) stack tests and compliance would be demonstrated by stack tests. The change to use of CO CEMS for measurement and enforcement of the same emission limits must be carefully considered in relation to an appropriate averaging period for data reduction. In past EPA rulemakings for incineration units, EPA has selected averaging times between four hours and 24 hours based on statistical analysis of long-term CEMS data for a particular subcategory. Because sufficient CO CEMS data are unavailable for CISWI to perform such an analysis and determine an emission level that would correspond to a shorter averaging period, EPA concluded that the use of a 24-hour block average was appropriate to address potential changes in CO emissions. The 24-hour block average would be calculated following procedures in EPA Method 19 of appendix A-7 of 40 CFR part 60. Facilities electing to use CO CEMS as an optional method would be required to notify EPA one month before starting use of CO CEMS and one month before stopping use of the CO CEMS. In addition, EPA specifically requests comment on whether continuous monitoring of CO emissions should be required for all existing CISWI.

PM CEMS.

The proposed amendments would allow the use of PM CEMS as an alternative testing and monitoring method (except for energy recovery units with a heat input capacity greater than 250 MMBtu/hr which are required to use them). Owners or operators who are required to use, or choose to rely on, PM CEMS would be able to discontinue their annual PM compliance test. In addition, because units that demonstrate compliance with the PM emission limits with a PM CEMS would also be meeting the opacit

This text is long and has been trimmed here. Open the source document for the complete record.

This is a copy of a public record, reproduced as it was published. It is not legal advice, and it may not be the version a court would rely on. Check the official source before you cite it.