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What’s a Solid Waste? U.S. EPA Finalizes the Definition of Solid Waste (DSW) Rule

Posted: March 6th, 2011

Author: All4 Staff 

The final Definition of Solid Waste (DSW) rule was signed by U.S. EPA on February 21, 2011 and is expected to be published in the Federal Register in March 2011. The purpose of the DSW rule is to clarify which non-hazardous secondary materials are, or are not, Resource Conservation and Recovery Act (RCRA) Subtitle D solid wastes when burned as fuel or ingredients in combustion units. U.S. EPA recognizes that the DSW rule will significantly narrow the current universe of non-hazardous fuels allowed to be burned in combustion units. Many materials that have been historically combusted as alternate fuels or used as alternate ingredients will not likely meet the non-waste determination requirements of the DSW rule. As a result, such materials will be reclassified as solid waste, and in accordance with Section 129 of the Clean Air Act, may only be combusted in a unit that is regulated under the Standards of Performance for New Stationary Sources and Emission Guidelines for Existing Sources: Commercial and Industrial Solid Waste Incineration Units (CISWI) rule. Both the DSW and CISWI rules were finalized with the infamous National Emission Standards for Hazardous Air Pollutants for Major Sources: Industrial, Commercial, and Institutional Boilers and Process Heaters (Major Source Boiler Rule) and National Emission Standards for Hazardous Air Pollutants for Area Sources: Industrial, Commercial, and Institutional Boilers (Area Source Boiler Rule). Based on U.S. EPA data, ALL4 anticipates that over 200,000 sources may be affected by these “4 Rules.” 

While portions of the Major Source Boiler Rule, Area Source Boiler Rule, and CISWI Rule may be reconsidered by U.S. EPA, the DSW rule, as-is, will likely remain intact and will become effective 60 days after its publication in the Federal Register. The DSW Rule is anticipated to have an immediate impact on facilities that are currently using, or considering the use of, secondary materials as alternate fuels since there is no multi-year compliance timeline associated with the DSW rule. Permitting authorities may be hesitant to authorize the use of secondary materials as alternate fuels, even on a trial basis, if those materials do not meet the non-waste criteria of the DSW rule. 

The final DSW Rule defines the criteria used to determine which non-hazardous secondary materials are, or are not, solid wastes when utilized in combustion units or kilns as alternate fuels. The significance of utilizing alternate fuels that are characterized as “waste” versus “non-waste” is:

    • Non-hazardous secondary materials that are considered solid wastesunder RCRA would subject a combustor (e.g., boiler, cement kiln, etc.) to the section 129 Clean Air Act (CAA) CISWI Rule requirements.

    • Non-hazardous secondary materials that are not considered solid wastesunder RCRA would subject a boiler or industrial furnace to the section 112 CAA Major Source Boiler or Area Source Boiler Rule requirements.
  • Cement kilns that utilize non-wastes as alternate fuel would remain subject to the existing Portland Cement NESHAP requirements.

The final DSW Rule maintains the basic framework of the June 2010 proposed rule, specifying that non-hazardous secondary materials that are burned in combustion units are solid waste unless:

  • The material is used as fuel and remains within control of the generator and meets the legitimacy criteria of the DSW rule;
  • The material is used as an ingredient in a manufacturing process and meets the legitimacy criteria;
  • Discarded material has been sufficiently processed to produce a fuel or ingredient that meets the legitimacy criteria; or
  • The material, that has not been discarded and handled outside the control of the generator, has been determined through a case-by-case petition process to be indistinguishable in all relevant aspects from a fuel product.

In response to comments and additional information received, U.S. EPA included several significant changes in the final rule which are favorable to combustors of select secondary materials as alternate fuels. Specifically,

  • Scrap Tires – Under the 2010 proposed DSW rule, scrap tires were considered solid waste when combusted unless they were sufficiently processed (e.g., shredded and metal removal). The final rule specifically exempts tires that have been removed from vehicles that have been managed under an established tire collection program. Tires meeting this standard are considered to be non-waste and can continue to be utilized as alternate fuels in cement kilns and other tire derived fuel (TDF) combustion devices, with or without processing.
  • Resinated Wood Residuals – Under the 2010 proposed DSW rule, resinated wood residuals that were transferred to another facility and not controlled by the generator were considered solid waste when combusted, unless they were sufficiently processed. In the final rule, U.S. EPA has concluded that resinated wood residuals, when burned in a combustion unit, whether in control of the generator or not, would not be a solid waste, provided it meets the legitimacy criteria.
  • Coal Refuse – Under the 2010 proposed DSW rule, abandoned coal refuse which was processed was considered solid waste when combusted. In the final DSW rule, U.S. EPA has determined that coal refuse that is processed the same as coal, which serves to both increase energy value and reduce contaminants, is not a solid waste.
  • Traditional Fuels – In response to comments, the definition of traditional fuels has been expanded to include an “alternative traditional fuel” category. Alternative traditional fuels include: specification used oil, mined coal refuse, and clean cellulosic biomass. The new definition of traditional fuels also clarifies that traditional fuels are not secondary materials and are not solid waste unless discarded.


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