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Region 1: EPA New England

What Kinds of Combustion Units Are There?

There are several types of combustors that may be used to burn waste. These include: 1) large municipal waste combustors; 2) small municipal waste combustors; 3) hospital/medical/infectious waste incinerators; 4) commercial and industrial solid waste incineration units; 5) other solid waste incinerators; 6) sewage sludge incinerators; 7) hazardous waste incinerators and manufacturing waste incinerators; 8) boilers and industrial furnaces that burn solid waste; and 9) industrial, commercial, and institutional boilers that do not burn solid waste. Combustors in categories 1-6 are regulated under Section 129 of the Clean Air Act. Combustors in categories 7 and 8 are regulated under the Resource Conservation Recovery Act (RCRA), and the Toxics Substances Control Act (TSCA). Combustors in category 9 are regulated under the National Emission Standards for Hazardous Air Pollutants (NESHAP) program.

Learn more about EPA's definition of solid waste.

Presently, in New England, there are facilities in all of the above categories except Category 7.

Several recent court decisions may affect the exact definitions of some of these categories.

You may find out more about the regulations affecting each category by clicking on the title.

  1. Large Municipal Waste Incinerators (LMWCs)
    Large municipal waste combustors are incinerators which are capable of burning greater than 250 tons of municipal waste per day and which burn household, commercial, and/or institutional waste. Burning waste reduces its volume before disposal into a landfill. Municipal waste combustors include the subcategory of waste-to-energy plants which generate electricity or steam from burning waste. Presently, there are 14 LMWCs in New England.
  2. Small Municipal Waste Incinerators (SMWCs)
    Smaller communities may be served by incinerators similar to those in Category 1, except that they only burn 35 to 250 tons of waste per day. There are five plants in New England that are classified as SMWCs.
  3. Hospital/Medical/Infectious Waste Incinerators (HMIWIs)
    Hospital/medical/infectious waste incinerators (medical waste incinerators) are incinerators used by the hospitals, health care facilities, and commercial waste disposal companies to burn hospital, medical, and infectious wastes. Burning this waste reduces its volume and kills pathogens/diseases in the waste material. There is one HMIWI unit in New England.
  4. Commercial and Industrial Incinerators (CISWIs)
    EPA has passed regulations and guidelines for the fourth type of incinerator. The regulations and guidelines apply to incinerators used by commercial and industrial facilities to burn non-hazardous solid waste. Presently, there are no CISWIs in New England.
  5. Other Solid Waste Incinerators (OSWIs)
    Presently, two types of incinerator, very small municipal waste combustors (VSMWCs) and institutional waste incinerators (IWIs), fall into this category. Very small municipal waste combustors are municipal waste combustors which burn less than 35 tons per day. Institutional waste incinerators are used by schools, churches, prisons, etc. to burn the waste generated by these facilities. There is one VSMWC in New Hampshire and one facility in Massachusetts which may be classified and an IWI. Several other OSWIs in New England have recently ceased operation.
  6. Sewage Sludge Incinerators (SSIs)
    Sewage Sludge Incinerators (SSIs) are units which combust sewage sludge to reduce its volume and remove materials which might be flammable. SSIs are usually located at waste water treatment plants. Since they are not specifically identified in Section 120(a)(1)(A) thru (D), they were previously considered to be OSWIs. EPA has determined that they are sufficiently unique to make it worthwhile to prepare a separate Rule to regulate them. EPA began this process by publishing a proposed rule in the Federal Register on October 14, 2010. There are 14 SSIs in New England.
  7. Hazardous Waste and Manufacturing Waste Incinerators
    These incinerators are different than those described in the proceeding paragraphs due to kinds of waste that they burn. Manufacturing Waste Incinerators are ones that can burn non-household waste from a given manufacturing process. This type of combustor is regulated under RCRA or the hazardous waste regulations. These units can be either located at a manufacturing facility or at a facility that is permitted by either EPA or the states to treat, store or dispose of hazardous waste. A purpose of the units is to reduce the amount of waste that must be shipped or dispose of from the facility. Hazardous Waste incinerators burn wastes such as PCBs or Polychlorinated Biphenyls which are toxic. These combustors are regulated under TSCA. Although there are a number of these two types of incinerators operating in the US there are no Hazardous Waste or Manufacturing Waste Incinerators in New England.
  8. Boilers and Industrial Furnaces
    There is another class of combustion units that can burn wastes regulated under RCRA, these are boilers and industrial furnaces. These units can be found in industrial settings. The waste must have an energy value, i.e., BTUs before it can be burned in these units. The energy that is recovered is reused in the manufacturing process. There are two such units in New England.
  9. Industrial, Commercial, and Institutional Boilers
    Commercial boilers which do not burn solid waste, as defined by EPA, include those found in stores/malls, laundries, apartments, restaurants, and hotels/motels. Institutional boilers are found in many locations, including medical centers (hospitals, clinics, nursing homes), educational and religious facilities (schools, universities, churches), amusement parks, and municipal buildings (courthouses, prisons). Industrial boilers are found in manufacturing, processing, mining, and refining or any other industry.

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