Commercial and Industrial Solid Waste Incineration Units

(CISWI); Reconsideration and Final Rule Amendments (SAN 5105.1) 4. Removal of the Definition of “Homogeneous Waste” The EPA included in the final 2011 CISWI Rule a definition of homogenous waste and a process for evaluating claims that a particular waste stream is homogenous. The definition was added to the 2011 CISWI rule in response to comment. Because the determination of homogeneity of a waste stream is relevant to applicability of CAA section 129 to qualifying small power producers and qualifying cogeneration facilities, we determined it was reasonable to include a definition of “homogenous waste” and a process by which sources could obtain a determination that a waste stream is homogenous fro m the EPA. In the 2011 CISWI Rule, the EPA stated that a determination concerning whether a waste is homogeneous is made on a case

- by

case basis. The EPA added provisions to the CISWI final rule that require source owners or operators seeking the exemptio n to submit a request for a homogeneous waste determination to the EPA, and that they support their request with information describing the materials to be combusted and why they believe the waste is homogeneous. The 2011 CISWI rule also stated that the de termination of what constitutes a homogeneous waste is not delegable to the state or local agencies. In the December 23, 2011, reconsideration proposal, we proposed for comment thedefinition of “homogeneous waste” and the provisions for making

homogeneous waste determinations that were included in the 2011 CISWI rule. Commenters generally did not agree with the proposed definition and provisions for making a homogeneous waste determination, arguing that the definition and provisions introduced ambiguities and stipulations that would prevent classification of many materials (including fossil fuels) as being “homogeneous.” We reevaluated the definition and provisions in light of the comments and determined that the definition and provisions could be interpre ted in a manner that would be unduly restrictive; however, we also determined that commenters proposed alternative definitions and provisions were equally problematic. Therefore, the final rule does not include a definition of “homogeneous waste”. We are also removing the requirement that qualifying small power producers and qualifying cogeneration facilities that combust solid waste obtain a determination from EPA that such waste is homogenous. Because the final rule does not include a homogenous waste definition or a process to obtain a determination from EPA, we believe that it is appropriate to inform the EPA when a unit qualifies as a small power generator or cogeneration facility as defined under section 129 because the site specific fact patterns f or different types of waste may vary considerably. Therefore, thefinal rule requires qualifying small power producers and

qualifying cogeneration facilities that combust solid waste notify the EPA that such waste is homogeneous. (40 CFR 60.2020 and 40 CFR 60.2555). Section 129 states, in part, that the term “solid waste incineration unit” does not include:

...qualifying small power production facilities, as defined in section 796 (17)(C) of title 16 , or qualifying cogeneration facilit ies, as defined in section 796 (18)(B) of title 16 , which burn homogeneous waste ( such as units which burn tires or used oil, but not including refuse

- derived fuel ) for the production of electric energy or in the case of qualifying cogeneration facilities which burn homogeneous waste for the production of electric energy and steam or forms of useful energy (such as heat) which are used for industrial, commercial, heating or cooling purposes... CAA Section 12 9(g)(1)(B) ( emphasis added ) We believe that the parenthetical contained in the exemption that prohibits refuse derived fuel, which is made from municipal solid waste, from qualifying as homogenous waste and allows tires and used oil to qualify as homoge nous wastes provides guidance on what constitutes a homogenous waste. We donot accept industry’s assertion that any waste from a common

source is homogeneous, or that in all cases combining two homogeneous wastes results in a homogeneous waste, as doing so could result in almost any waste stream being homogenous. We do not believe that is consistent with the statute. Instead, we believe Congress intended this exemption to apply only when the waste stream has a consistent makeup that allows the source and the enforcement authority to predict the range of emissions from the combustion of the waste on an ongoing basis. In keeping with this interpretation, we maintain that the homogeneous wastes are generally material specific (e.g. tires or used oil). We believe this means that a homogeneous waste is of known origin and that it can be identified as a specific material or materials

– using the example in the Act, certain used oils or scrap tires. By contrast, municipal solid waste can be identified as muni cipal solid waste as a general term, but it is not composed of only one or two specific type of waste; e.g. municipal solid waste cannot be identified as one specific material or group of materials. Regarding variability of the composition of homogeneous waste throughout, homogeneous waste may have variations in composition, but it should generally be within the range of operations which produce the waste (e.g. size, contaminant levels, state of matter.) We also believe that off

- spec materials may be homo geneous, even if they are nothomogeneous to the on

- spec material, and that, if combusted

together, both the on

- spec and off

- spec materials may require separate homogenous waste determinations. We also believe that homogeneous waste should have predictabl e known contaminant levels, even if those contaminant levels vary within a range. We may question the homogeneity of a specific material if it is adulterated such that it takes on the characteristics of a different type of waste (e.g. used oil which is so contaminated with PCB’s from a leaking heat exchanger, such that the used oil takes on the characteristics of a waste PCB stream as opposed to a used oil stream) or where the BTU value of a waste is so altered that other fuels must be introduced to ensure combustion and preserve the purpose of combustion under the exemption, i.e. to produce energy.