In the U.S more than 3.1 millions tons of hazardous waste were disposed of through combustion in 2005. This figure represents 7.2 percent of the approximately 44 million tons of hazardous waste generated (source: 2005 National Biennial RCRA Hazardous Waste Report, December 2006, EPA530-R-06-006). For additional information, see:
- Types of Hazardous Waste Combustion Units
- Air Emissions Regulations for Hazardous Waste Combustors
- Exclusion of Hazardous Waste-Derived Fuel and Synthesis Gas
- Background Information and Guidance
- Risk Assessment
- Economic Assessment
- Related Topics
Types of Hazardous Waste Combustion Units
There are two categories of combustion units for solid and liquid hazardous wastes:
- Incinerators - used primarily for waste destruction.
- Boilers and Industrial Furnaces (BIFs)- used primarily for energy and material recovery.
Incinerators are used to burn hazardous waste primarily for waste destruction/treatment purposes; however, some energy or material recovery can occur.
When performed properly, incineration destroys the toxic organic constituents in hazardous waste and reduces the volume of the waste. Since metals will not combust, incineration is not an effective method for treating metal-bearing hazardous wastes. There are many types of hazardous waste incinerators including:
- Rotary kilns
- Fluidized bed units
- Liquid injection units
- Fixed hearth units
Boilers and Industrial Furnaces (BIFs)
BIFs are typically used to burn hazardous waste for the significant energy and material recovery potential, with waste treatment being a secondary benefit. Boilers typically combust waste for energy recovery, while industrial furnaces burn waste for both energy and material recovery.
A boiler is defined as an enclosed device that uses controlled flame combustion to recover and export energy in the form of steam, heated fluid, or heated gases.
An industrial furnace is a unit that is an integral part of a manufacturing process and uses thermal treatment to recover materials or energy. The following units are considered industrial furnaces:
- Cement kilns
- Lime kilns
- Aggregate kilns
- Phosphate kilns
- Coke ovens
- Blast furnaces
- Smelting, melting, and refining furnaces
- Titanium dioxide chloride process oxidation reactors
- Methane reforming furnaces
- Halogen acid furnaces
- Pulping liquor recovery furnaces
- Combustion device used in the recovery of sulfur values from spent sulfuric acid
RCRA regulations governing boilers and industrial furnaces can be found at 40 CFR Part 266, Subpart H-Hazardous Waste Burned in Boilers and Industrial Furnaces.
Air Emissions Regulations for Hazardous Waste Combustors
Hazardous waste combustors also are regulated under the Clean Air Act (CAA). The CAA protects human health and the environment from the harmful effects of air pollution by requiring significant reductions in the emissions of the most dangerous air pollutants. These pollutants are known or suspected to cause serious health problems such as cancer or birth defects, and are referred to as hazardous air pollutants (HAPs).
As originally enacted, the CAA required that EPA establish National Emission Standards for Hazardous Air Pollutants (NESHAPs) on a chemical-by-chemical basis. Under this mandate, EPA established NESHAPs for seven HAPs. However, the 1990 amendments to the CAA changed EPA's approach to regulating HAPs, so that NESHAPs are now established based on the "maximum achievable control technology" (MACT) for an industry group or source category (for example, hazardous waste combustors). These standards are based on emission levels that are already being achieved by the better-performing sources within the group.
The NESHAP for hazardous waste combustors was developed in two phases. Phase I, which addresses hazardous waste burning incinerators, cement kilns, and lightweight aggregate kilns, was originally promulgated on September 30, 1999 (64 FR 52828). Hazardous waste burning industrial boilers, process heaters, and hydrochloric acid production furnaces, were addressed in Phase II, which was signed September 14, 2005. Replacement standards for Phase I also were signed on this date.
For more information on implementation of the Hazardous Waste Combustion NESHAP (40 CFR Part 63, Subpart EEE), visit the Hazardous Waste Combustion NESHAP Toolkit.
Comparable Fuel Exclusion (CFE), 1998: Hazardous waste-derived fuels are excluded from the regulatory definition of solid waste if they meet specification levels comparable to fossil fuels for concentrations of hazardous constituents and for physical properties that affect burning. The exclusion applies to the comparable fuel from the point it is generated and is claimed by the person generating the comparable fuel (which person can include a hazardous waste treater). Generators of the comparable fuel must comply with sampling and analysis, notification and certification, and record keeping requirements. The exclusion applies to liquid hazardous waste-derived fuels and synthesis gas derived from hazardous waste. EPA promulgated the comparable fuel exclusion (63 FR 33782) (PDF) (48 pp, 399 K) on June 19, 1998.
Emission Comparable Fuel Expansion (ECF), 2008:
EPA expanded the Comparable Fuels Exclusion to encompass a new category of liquid hazardous secondary materials known as emission-comparable fuel (ECF). By expanding the Comparable Fuels Exclusion, ECF will be handled as a valuable commodity.
ECF is subject to the same regulations that currently apply to the Comparable Fuels Exclusion, with the exception of those for oxygenates and hydrocarbons (constituents which contribute energy value to the fuel). The rule specifies conditions on burning ECF which assure that emissions from industrial boilers burning ECF are comparable to emissions from industrial boilers burning fuel oil. The ECF exclusion also includes conditions for tanks and containers storing ECF to prevent improper disposal.
For more information on the comparable fuel exclusion and the emission comparable fuel expansion , visit Comparable Fuel Exclusion and Technical Information page.
Background Information and Guidance
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Training Module: "Introduction to Hazardous Waste Incinerators" (PDF) (17 pp, 28K) | Text
File (February 2000)
This document provides an overview of the RCRA regulations governing hazardous waste incinerators found in 40 CFR Parts 264 and 265, Subpart O. The document includes an overview of what an incinerator is and how incinerators are regulated.
Training Module: "Introduction to Boilers and Industrial Furnaces" (PDF) (22 pp, 30K | Text
Version (February 2000)
This document provides an overview of the RCRA regulations governing boilers and industrial furnaces (BIFs) found in 40 CFR Part 266, Subpart H. The document includes an overview of the requirements for processing hazardous waste in BIFs, including the distinctions between permitted and interim status units, and explains the requirements for specially regulated BIF units.
on Emergency Incidents at Hazardous Waste Combustion Facilities and Other
Treatment, Storage, and Disposal Facilities (TSDFs) (PDF) (47 pp, 137K) (June 1999)
This report provides a compilation of information on reported emergency incidents at hazardous waste combustion facilities and other TSDFs regulated under the Resource Conservation and Recovery Act (RCRA). It is limited to emergency incidents such as fires, explosions, hazardous waste spills, or unauthorized releases of hazardous waste. The information contained in this report was obtained from Regional and State waste combustion experts and permit writers.
Clarification of the Land Disposal Restrictions' Dilution Prohibition and
Combustion of Inorganic Metal-Bearing Hazardous Wastes(May 1994)
This EPA memo presents a Statement of Policy under the Resource Conservation and Recovery Act (RCRA) clarifying the application of the Land Disposal Restrictions prohibition on dilution (40 CFR Part 268.3) to combustion of certain inorganic metal-bearing hazardous wastes. The memo addresses the question of whether combustion of prohibited inorganic hazardous wastes can be a type of impermissible dilution. Presents distinctions between "adequate treatment" and potential violations of the dilution prohibition. The memo advocates the treatment of metal-bearing hazardous wastes by metal recovery or stabilization techniques over combustion methods. An appendix containing descriptions of wastes affected by the guidelines set forth in this Policy is included.
Risk assessment is the qualitative and quantitative evaluation of the risk posed to human health and/or the environment by the actual or potential presence or use of specific pollutants. Risk assessments relating to hazardous waste combustion examine the potential risk posed by the operations of these facilities. For more information on risk assessment and EPA's risk assessment guidelines, visit EPA's National Center for Environmental Assessment.
For additional information on hazardous waste combustion risk assessment, see the following documents:
- Human Health
Risk Assessment Protocol (HHRAP) for Hazardous Waste Combustion Facilities
- Final (September 2005)
This document primarily focuses on the procedures used to estimate risk resulting from indirect pathways in relation to hazardous waste combustion facilities, but also describes the evaluation of direct inhalation risk. The document updates and replaces the 1998 Peer Review Draft version of the HHRAP (EPA530-D-98-001).
- Human Health Risk Assessment Protocol for Hazardous Waste Combustion Facilities, Support Materials
- Technical Support Documents: Risk TSDs
- Human Health and Ecological Risk Assessment Comment Response Documents
- Risk Burn Guidance for Hazardous Waste Combustion Facilities (PDF) (199 pp, 408K) (July
This document contains EPA's recommendations regarding stack emissions tests which may be performed at hazardous waste combustion facilities for the purpose of supporting multi-pathway, site-specific risk assessments, where such a risk assessment has been determined to be necessary by the permit authority. The guidance recommends combustor operating and feed conditions that should generally be demonstrated during the testing, and identifies stack sampling and analytical techniques for collection of the emissions data. In addition, the relationship between test conditions and potential RCRA permit conditions is discussed.
Level Ecological Risk Assessment Protocol for Hazardous Waste Combustion
Facilities - Peer Review Draft (November 1999)
This document expands on the general guidance regarding the ecological risk assessment process with respect to the ecological screening level procedures, and provides a prescriptive tool to support permitting of hazardous waste burning combustion facilities under the Resource Conservation and Recovery Act (RCRA).
- American Society of Mechanical Engineers
(ASME) Hazardous Waste Incinerator Operator Certification Program
This certification program is intended for individuals directly involved with the operation of hazardous waste incinerators. Note: This program has been sunsetted by ASME as of December 31, 2010. Applications for new certifications are no longer being accepted. Current certificates will remain valid through the expiration date listed on the certificate.
Public Participation and Permitting
This website provides information to help make it easier for citizens to become involved earlier and more often in the process of permitting hazardous waste facilities, including hazardous waste combustion units.
- EPA's Air Pollution Technology Branch (part of EPA's National Risk Management Research Laboratory) conducts research on air pollutant emissions generated during the process of hazardous waste incineration.