March 29, 2011

Combustion Rules and a RCRA Definition

On February 21, 2011, EPA announced four CAA actions and one RCRA action that have significant implications for industrial combustion. Most entities will be affected by the Agency’s final NESHAP emitted at major and area sources of pollution. EPA estimates that compliance will be required for about 200,000 boilers nationwide.

According to EPA, the final boiler NESHAPs differ significantly from those proposed in June 2010 following the Agency’s receipt of substantial amounts of new information from industry. Areas where the proposals were modified include emissions limits, compliance mechanisms, and subcategories. The Agency indicates that these changes will result in more than $1.7 billion in reduced compliance costs compared to costs anticipated in the proposal.

Additional CAA combustion rules were published for commercial/industrial solid waste incinerators and sewage sludge incinerators. The RCRA rule identifies which nonhazardous secondary materials are or are not solid wastes when burned in combustion units.

Following are important elements in each of the actions as well as EPA’s notice that it will reconsider some of those elements as more information is analyzed.

NESHAP for Major Sources: Industrial, Commercial, and Institutional Boilers and Process Heaters. The rule addresses the combustion of nonsolid waste materials in boilers and process heaters located at major sources of HAPs. With several notable exceptions, the NESHAP establishes numeric emissions limits for mercury, dioxin, particulate matter (PM, as a surrogate for nonmercury metals), hydrogen chloride, and carbon monoxide (CO). Emissions limits are established for new and existing sources in 15 subcategories, with the subcategories differing on the basis of unit design.

In the final rule, EPA added a limited-use subcategory that was not contemplated in the proposal. Industry persuaded the Agency that limited-use boilers spend a larger percentage of time in start-up, shutdown, or other reduced-efficiency operating conditions than continuously operated units. Commenters said that making limited-use units subject to numeric emissions limits would be technically infeasible. The rule therefore requires that limited use units comply with work practice standards that include a biennial tune-up. In addition:

• Units that combust only natural gas, refinery gas, or equivalent fuel are subject to a work practice standard in lieu of numeric emissions limits. The work practice standard requires an annual tune-up and other actions to minimize periods of start-up and shutdown.
• Units with a heat input capacity less than 10 MMBtu/hr are subject to a work practice standard that includes a tune-up once every 2 years.
• Existing major source facilities are required to conduct a one-time energy assessment to identify cost-effective energy conservation measures.
• Compliance dates differ for new and existing sources.

NESHAP for Area Sources: Industrial, Commercial, and Institutional Boilers. EPA withdrew its proposed numeric emissions limits for biomass and oil-fired units as well for as small units and replaced these with management or work-practice standards. Emissions limits and work practice standards are imposed as follows:

• New coal-fired boilers with heat input equal to or greater than 10 MMBtu/hr must meet numeric emissions limits for mercury, PM, and CO. New biomass and oil-fired boilers with heat input equal to or greater than 10 MMBtu/hr must meet emissions limits for PM. New boilers with heat input less than 10 MMBtu/hr must meet the work practice standard of a boiler tune-up every 2 years.
• Existing coal-fired boilers with a heat input equal to or greater than 10 MMBtu/hr must meet numeric emissions limits for mercury and CO. Numeric emissions limits are not required for existing biomass boilers, oil-fired boilers, and small coal-fired boilers; instead these units must meet a work practice standard by performing a boiler tune-up every 2 years.
• For numeric emissions limits, compliance will be required 3 years after the rules are published in the FR. Compliance with work practice standards is required 1 year after publication.
• All existing boilers with a heat input equal to or greater than 10 MMBtu/hr are subject to a one-time energy assessment by qualified personnel to identify cost-effective energy conservation measures.

Standards of Performance for New Stationary Sources (NSPS) and Emissions Guidelines (EG) for Existing Sources: Commercial and Industrial Solid Waste Incineration Units (CISWI). This action responds in part to vacatur by the U.S. Court of Appeals for the D.C. Circuit of EPA’s 2005 definitions rule. The applicability of that rule was limited to units that combusted commercial or industrial waste and were not designed to or did not operate to recover thermal energy from the combustion. The court held that solid waste incineration units “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)].” The current action also fulfills EPA’s obligation under the CAA to conduct a 5-year review of EGs for new and existing CISWI. EPA estimates that the rule covers approximately 100 incinerators, cement kilns, and energy recovery units (ERUs).

• Numeric emissions limits are established for mercury, lead, cadmium hydrogen chloride PM, CO, dioxins/furans, nitrogen oxides, and sulfur dioxide. The limits vary based on whether the unit is an incinerator, an ERU burning solids, an ERU burning liquid or gas, a waste-burning kiln, or a small remote incinerator.

Additional requirements apply to demonstration of initial compliance with the emissions limits, stack testing, monitoring, inspections of emissions control devices, and annual visible emissions tests of ash handling operations.

Identification of Nonhazardous Secondary Materials that Are Solid Waste. Whether a unit is a boiler subject to either the NESHAP or an incinerator subject to the NSPS depends on what is being combusted. Accordingly, this RCRA rule identifies which nonhazardous secondary materials, when used in a combustion unit, are or are not solid wastes. EPA applies well-established legitimacy criteria to the identification of solid wastes or nonsolid wastes, including whether the material has been discarded; if it has been discarded, has it been sufficiently processed to produce a new nonwaste fuel or ingredient product; if it is managed as a valuable commodity; and if it contains contaminants that are comparable to or lower than contaminants in traditional fuel products. A more recently established criterion is whether the material is used as a fuel and remains within the control of the generator (whether at the site of generation or another site the generator has control over).

Under the final rule, examples of nonhazardous secondary materials designated as solid wastes when burned include:

• Whole scrap tires from waste tire piles
• Off-specification used oil
• Sewage/wastewater treatment sludge
• Contaminated construction and demolition material
• Chromate copper arsenate treated wood

Examples of secondary materials designated not to be solid wastes (if they meet the legitimacy criteria) when burned in combustion units include:

• Clean biofuels/biogas processed from solid waste
• Scrap tires removed from vehicles and managed under established tire collection programs and tire-derived fuel from the processing of scrap tires removed from tire piles (shredded with the steel belts and wire removed)
• Materials, such as cement kiln dust, coal ash, and foundry sand, that are used as ingredients in manufacturing processes (e.g., in cement kilns).

NSPS and EG for Existing Sewage Sludge Incineration (SSI) Units. The final rule sets numeric limits for cadmium, CO, hydrogen chloride, lead, mercury, nitrogen oxides, PM, dioxins/furans, and sulfur dioxide. The specific limits differ based on whether the SSI is a fluidized bed or a multiple hearth operation. Also:

• All new and existing SSI units must demonstrate initial and annual compliance with the emissions limits using EPA-approved emissions test methods.
• Less frequent testing is available for sources that demonstrate that their emissions of regulated pollutants are below the emissions limits.
• For existing units, owners/operators must conduct annual emissions performance tests (or continuous emissions monitoring or continuous sampling as an alternative), bag leak detection for fabric filter controlled units, continuous parameter monitoring, and annual inspections of air pollution control devices.
• Visible emissions testing of ash-handling operations is also required.
• New units must be in compliance with the NSPS within 6 months after the promulgation date of the standards or at start-up, whichever is later.
• Compliance with EGs, which are implemented by the states, is required no later than 3 years after EPA’s approval of a state plan or within 5 years after publication of the EGs in the FR.

Notice of Reconsideration. Finally, EPA announced that it would reconsider certain aspects of the boiler and CISWI rules. According to the Agency, comments on the proposals for these rules raised difficult technical questions, the resolution of which would benefit from additional public comment.

Elements of the rules that EPA intends to reconsider include:

• Subcategories in the major source boilers rule,
• Establishing work practice standards for limited-use major source boilers,
• Establishing standards for biomass and oil-fired area source boilers based on generally available control technology,
• Revising the proposed subcategory for energy recovery units for CISWI units,
• Establishing limitations on fuel switching provisions for CISWI units,
• Revising the proposed definition of CISWI to exclude cyclonic burn barrels, and
• Providing an affirmative defense for malfunction events for major and area source boilers and for CISWI units.

The SSI rule is not part of this reconsideration.

All the above actions are at http://www.epa.gov/airquality/combustion/actions.html#feb11.