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ACTION PLEASE BY:
June 25, 2010

On April 30, the U.S. Environmental Protection Agency (EPA) proposed National Emission Standards for Hazardous Air Pollutants (NESHAP) for industrial, commercial, and institutional boilers at area sources that may affect the boilers used at publicly owned treatment works (POTWs). This proposed rule , published in the Federal Register on June 4, is part of a suite of proposed rules on the regulation of commercial and industrial incinerators and boilers under the Clean Air Act (CAA), including proposed NESHAP for boilers at major sources and a proposal from EPA’s waste office that defines sewage sludge destined for incineration as a solid waste. See Advocacy Alert 10-11 for more information about the sewage sludge definition proposal.

NACWA plans to submit comments on the proposed NESHAP for boilers by the August 3 deadline and would like members to provide input. This Advocacy Alert provides additional information on EPA’s proposal and asks members to provide input to NACWA’s Cynthia Finley at This e-mail address is being protected from spambots. You need JavaScript enabled to view it by June 25, 2010.

Background Information

Section 112(d) of the Clean Air Act (CAA) requires EPA to establish NESHAP for both major and area sources of hazardous air pollutants (HAP). A major source emits at least 10 tons per year (tpy) of a single HAP or at least 25 tpy of combined HAP, while an area source is a stationary source that emits HAP at levels below a major source. EPA may establish standards for emissions based on maximum achievable control technology (MACT), which for existing sources must be as stringent as the average emission limitation achieved by the best performing 12 percent of sources and for new sources must be as stringent as the emission controls in the best-controlled similar sources. In some cases, EPA may establish a generally available control technology (GACT) instead of a MACT.

EPA originally proposed NESHAP for boilers in 2003 and NACWA submitted comments on this proposal. The final rule was promulgated in 2004, but was vacated in 2007 by the U.S. Court of Appeals for the District of Columbia. This ruling required EPA to revise the NESHAP and its MACT floors for boilers, and to revise its definition of solid waste. Under EPA’s current proposed approach, combustion units burning solid wastes would be regulated under Section 129 of the CAA, while combustion units burning other materials would be regulated under Section 112 of the CAA. EPA believes that the boilers subject to the proposed area source rule combust coal, oil, and biomass.

Requirements of Proposed NESHAP

The proposed rule would amend 40 CFR Part 63 Subpart JJJJJJ and would have different requirements based on various characteristics of the boiler:

• New versus existing boilers
• Boiler size:
  • Large boilers – heat input capacity greater than or equal to 10 million British thermal units per hour (MMBtu/hr)
  • Small boilers – heat input capacity less than 10 MMBtu/hr
• Type of fuel burned:
  • Coal – boiler burns at least 10 percent coal on an annual fuel heat input basis
  • Biomass – boiler burns biomass or biomass in combination with less than 10 percent coal on an annual fuel heat input basis (biomass is defined as wood and plant products and residues, animal manure, and animal litter)
  • Oil – boiler burns oil or oil combined with a gaseous fuel, unless it burns oil only during periods of gas curtailment

Boilers of any size burning natural gas are excluded from the proposed rules because EPA found that they do not emit any of the urban HAP that EPA needs to establish emissions limits for to meet CAA requirements.

Standards are proposed for particulate matter (PM), mercury, and carbon monoxide (CO). PM is used as a surrogate for the individual urban metal HAP other than mercury, and CO is used as a surrogate for organic compounds, including polycyclic organic matter (POM).

Emissions Requirements for Large Boilers
The table below shows the proposed GACT standards proposed for PM and the MACT emission limits for mercury and CO. EPA found that only coal-fired boilers must be regulated for mercury emissions to achieve the regulation of 90 percent of emissions that is required under section 112(c)(6) of the CAA. To meet this requirement for POM, however, CO emissions must be regulated for all three types of boilers, with CO used as the surrogate for POM.

New boilers must comply with the standards upon publication of the final rule or at startup, whichever is later. For existing boilers, initial compliance with these emissions limits must be demonstrated through stack tests or fuel analysis (for mercury) within three years of promulgation of the final rule. If initial compliance is demonstrated through stack tests, then annual stack test must be conducted to demonstrate continuous compliance. Additional monitoring requirements apply for boilers that must comply with the PM and mercury emission limits, depending on whether wet scrubbers or fabric filters are used, and monthly fuel records must be kept to show that no new fuel type or new mixture was used. If initial compliance for mercury emissions is demonstrated by fuel analysis, then a monthly fuel analysis must be conducted and the annual average must be maintained below the appropriate limit.

For boilers with heat input capacities greater than or equal to 100 MMBtu/hr, continuous monitoring for CO must be performed and the daily average CO emissions must be kept at or below the emissions limits.

For existing large boilers, the proposed NESHAP also requires that “qualified personnel” perform of an energy assessment on the boiler and the facility to identify cost-effective energy conservation measures, which could result in further decreases of mercury and POM emissions. A “cost-effective energy conservation measure” is defined as any measure that has a return of investment period of two years or less. EPA estimates that the energy assessment will cost between $2,500 and $55,000 per facility, depending on the size of the facility. EPA did not have enough information to determine if it would be economically feasible for facilities to implement the energy conservation measures identified in the assessment, and therefore the proposed rule does not contain any requirements for implementation. EPA is seeking comment regarding the economic feasibility of these measures.

The mercury and CO MACT standards for existing boilers were based on data collected by EPA on emissions from area source boilers, with the MACT floors set as the emission level from the top-performing 12 percent of boilers. For coal boilers, the mercury MACT was based on two boilers and the CO MACT was based on three boilers. The CO MACTs for biomass and oil boilers were based on eight boilers and 15 boilers, respectively.

Requirements for Small Boilers
For small boilers, the proposed NESHAP only requires implementation of a tune-up program to improve and maintain the combustion efficiency of the boiler. A tune-up must be conducted for initial compliance, followed by tune-ups every two years for continued compliance.

EPA established this work standard, rather than emissions limits, based on a technical and economic analysis of the impacts of emissions limits. The standard methods for measuring emissions of mercury, CO, and PM are not applicable to stacks with a diameter less than 12 inches, which are typically found on small boilers. Also, many area source boilers would require expensive modification to install sampling ports and a platform to access the stack. The results of an economic analysis showed that compliance costs would have a significant adverse economic impact on a majority of facilities with small boilers. EPA is seeking comment on whether 10 MMBtu/hr is the appropriate threshold for this work standard, or if a higher threshold could be used.

Startup, Shutdown, and Malfunction Periods
The proposed NESHAP does not contain different standards for periods of startup, shutdown, and malfunction (SSM). The 2008 decision of the U.S. Court of Appeals for the District of Columbia in Sierra Club v. EPA vacated the exemption for SSM events in emissions standards, and EPA believes that the proposed NESHAP must apply at all times. EPA states in the proposed rule that since the standards are daily or monthly averages, “over long averaging periods, startups and shutdowns will not affect the achievability of the standards.” EPA also believes “that malfunctions should not be viewed as a distinct operating mode” and that emissions during malfunctions do not need to be factored into the NESHAP.

Potential Alternative Requirements

As stated above, EPA currently does not believe that MACT-based requirements are necessary for biomass and oil boilers in order to meet CAA requirements for control of mercury emissions. If comments and further analysis cause EPA to change this decision, however, the proposed rule presents potential MACT standards for these large boilers as follows:

• Existing biomass boilers – 4 x 10^-7 lb/MMBtu (based on one area source boiler)
• Existing oil boilers – 4 x 10^-6 lb/MMBtu (the major source MACT, since no area source information is available)
• New biomass boilers – 4 x 10^-7 lb/MMBtu (based on one boiler)
• New oil boilers – 3 x 10^-7 lb/MMBtu (the major source MACT, since no area source information is available)

EPA is requesting comments on these potential MACT requirements, if they are determined to be necessary.

Input Needed

NACWA members are asked to provide input about the impacts of the proposed boiler NESHAP on POTWs. We would like to comment on the reasonableness of the proposed requirements, and address some of the specific requests for comments made by EPA in the proposed rule, including the following:

1. Are the MACT-based emissions limits for mercury and CO for large boilers appropriate and reasonable? Are the GACT-based emission limits for PM for large boilers appropriate and reasonable?
   
   
2. For the energy assessment requirement for large existing boilers are the estimates for conducting an assessment reasonable and is there adequate access to certified assessors? Is the definition of “cost-effective” appropriate since it refers to rate of return of energy saving investments without regard to the impact on HAP reduction? What rate of return should be used in this definition?
   
   
3. Is the threshold of 10 MMBtu/hr appropriate for differentiating between large and small boilers? Or would a higher threshold meet the technical and economic limitations specified in section 112(h) of the CAA?
   
   
4. Are the GACT- based standards for small boilers appropriate?
   
   
5. Are there any provisions related to SSM events that should be added to the regulatory text in light of the absence of an SSM exemption? Can the proposed emissions limits be met during SSM events?
   
   
6. Should a MACT-based mercury emission limit be established for large biomass and oil boilers as well as coal boilers? If the decision is made to do this, are the proposed MACT emission limits appropriate?
   
   

Please send your responses to Cynthia Finley at This e-mail address is being protected from spambots. You need JavaScript enabled to view it by June 25.