Definition of solid waste

Types of Solid Wastes The term solid wastes is aU-inchisive and encompasses all sources, types of classifications, compositions, and properties. As a basis for subsequent discussions, it will be helpful to define the various types of solid wastes that are generated. It is important to note that the definitions of solid-waste terms and the classifications vary greatly in prac tice and in literature. Consequently, the use of published data requires considerable care, judgment, and common sense. The following definitions are intended to serve as a guide. 

Hazardous waste identification begins with an obvious point in order for any material to be a hazardous waste, it must first be a waste. However, deciding whether an item is or is not a waste is not always easy. For example, a material (like an aluminum can) that one person discards could seem valuable to another person who recycles that material. U.S. EPA therefore developed a set of regulations to assist in determining whether a material is a waste. RCRA uses the term solid waste in place of the common term waste. Under RCRA, the term solid waste means any waste, whether it is a solid, semisolid, or liquid. The first section of the RCRA hazardous waste identification regulations focuses on the definition of solid waste. For this chapter, you need only understand in general terms the role that the definition of solid waste plays in the RCRA hazardous waste identification process. 

Materials that are recycled are a special subset of the solid waste universe. When recycled, some materials are not solid wastes, and therefore not hazardous wastes, but others are solid and hazardous waste, but are subject to less-stringent regulatory controls. The level of regulation that applies to recycled materials depends on the material and the type of recycling (Figure 13.2). Because some types of recycling pose threats to human health and the environment, RCRA does not exempt all recycled materials from the definition of solid waste. As a result, the manner in which a material is recycled will determine whether or not the material is a solid waste, and therefore whether it is... 

Wastes used as a product substitute. If a material is directly used as an effective substitute for a commercial product (without first being reclaimed), it is exempt from the definition of solid waste. 

Dioxin-containing wastes considered inherently waste-like. Dioxin-containing wastes are considered inherently waste-like because they pose significant threats to human health and the environment if released or mismanaged. As a result, RCRA does not exempt such wastes from the definition of solid waste even if they are recycled through direct use or reuse without prior reclamation. This is to ensure that such wastes are subject to the most protective regulatory controls. 

A material cannot be a hazardous waste if it does not meet the definition of a solid waste. Thus, wastes that are excluded from the definition of solid waste are not subject to the RCRA Subtitle C hazardous waste regulation. There are 20 exclusions from the definition of solid waste ... 

Irrigation return flows. When farmers irrigate agricultural land, water not absorbed into the ground can flow into reservoirs for reuse. This return flow often picks up pesticide or fertilizer constituents, potentially rendering it hazardous. Because this water may be reused on the fields, it is excluded from the definition of solid waste. 

Pulping liquors. Pulping liquor, also called black liquor, is a corrosive material used to dissolve wood chips for the manufacturing of paper and other materials. To promote waste minimization and recycling, U.S. EPA excluded pulping liquors from the definition of solid waste if they are reclaimed in a recovery furnace and then reused in the pulping process. If the liquors are recycled in another way, or are accumulated speculatively, they are not excluded. 

Spent sulfuric acid. Spent sulfuric acid may be recycled to produce virgin sulfuric acid. To promote waste reduction and recycling, such recycled spent sulfuric acid is excluded from the definition of solid waste, unless the facility accumulates the material speculatively. 

Closed-loop recycling. To further promote waste reduction and recycling, spent materials that are reclaimed and returned to the original process in an enclosed system of pipes and tanks are excluded from the definition of solid waste, provided that the following conditions are met ... 

Coke byproduct wastes. Coke, used in the production of iron, is made by heating coal in high-temperature ovens. Throughout the production process many byproducts are created. The refinement of these coke byproducts generates several listed and characteristic wastestreams. However, to promote recycling of these wastes, U.S. EPA provided an exclusion from the definition of solid waste for certain coke byproduct wastes that are recycled into new products. 

Splash condenser dross residue. The treatment of steel production pollution control sludge generates a zinc-laden residue, called dross. This material, generated from a splash condenser in a high-temperature metal recovery process, is known as a splash condenser dross residue. Because this material contains 50 to 60% zinc, it is often reclaimed, reused, or processed as a valuable recyclable material. Facilities commonly handle this material as a valuable commodity by managing it in a way that is protective of human health and the environment, so U.S. EPA excluded this residue from the definition of solid waste. 

Comparable fuels. In order to promote the recycling of materials with high fuel values, certain materials that are burned as fuels are excluded from the definition of solid waste, provided that they meet certain specifications (i.e., are of a certain degree of purity). This is to ensure that the material does not exceed certain levels of toxic constituents and physical properties that might impede burning. Materials that meet this specification are considered comparable to pure or virgin fuels. 

Processed scrap metal. Scrap metal includes, but is not limited to, pipes, containers, equipment, wire, and other metal items that are no longer of use. To facilitate recycling, scrap metal that has been processed to make it easier to handle or transport and is sent for metals recovery is excluded from the definition of solid waste. Unprocessed scrap metal is still eligible for an exemption from hazardous waste regulation when recycled. 

Shredded circuit boards. Circuit boards are metal boards that hold computer chips, thermostats, batteries, and other electronic components. Circuit boards can be found in computers, televisions, radios, and other electronic equipment. When this equipment is thrown away, these boards can be removed and recycled. Whole circuit boards meet the definition of scrap metal, and are therefore exempt from hazardous waste regulation when recycled. On the other hand, some recycling processes involve shredding the board. Such shredded boards do not meet the exclusion for recycled scrap metal. In order to facilitate the recycling of such materials, U.S. EPA excluded recycled shredded circuit boards from the definition of solid waste, provided that they are stored in containers sufficient to prevent release to the environment, and are free of potentially dangerous components, such as mercury switches, mercury relays, nickel-cadmium batteries, and lithium batteries. 

Mineral processing spent materials. Mineral processing generates spent materials that may exhibit hazardous waste characteristics. Common industry practice is to recycle these mineral processing wastes back into the processing operations to recover mineral value. U.S. EPA created a conditional exclusion from the definition of solid waste for these spent materials when recycled in the mineral processing industry, provided the materials are stored in certain types of units and are not accumulated speculatively. 

Petrochemical recovered oil. Organic chemical manufacturing facilities sometimes recover oil from their organic chemical industry operations. U.S. EPA excluded petrochemical recovered oil from the definition of solid waste when the facility inserts the material into the petroleum-refining process of an associated or adjacent petroleum refinery. Only petrochemical recovered oil that is hazardous because it exhibits the characteristic of ignitability or exhibits the toxicity characteristic for benzene (or both) is eligible for the exclusion. 

Spent caustic solutions from petroleum refining. Petrochemical refineries use caustics to remove acidic compounds such as mercaptans from liquid petroleum streams to reduce produced odor and corrosivity as well as to meet product sulfur specifications. Spent liquid treating caustics from petroleum refineries are excluded from the definition of solid waste if they are used as a feedstock in the manufacture of napthenic and cresylic acid products. U.S. EPA believes that spent caustic, when used in this manner, is a valuable commercial feedstock in the production of these particular products, and is therefore eligible for exclusion. 

Zinc fertilizers made from recycled hazardous secondary materials. U.S. EPA promulgated a conditional exclusion from the definition of solid waste for hazardous secondary materials that are recycled to make zinc fertilizers or zinc fertilizer ingredients. Zinc, an important micronutrient for plants and animals, can be removed from zinc-rich manufacturing residue and used to produce zinc micronutrient fertilizer. A second conditional exclusion applies to the zinc fertilizer products made from these secondary materials. 

U.S. EPA, Definition of Solid Waste and Hazardous Waste Recycling Module, U.S. EPA, Washington, DC, April 2006. 

This statutory definition of solid waste is pursuant to the regulations of the EPA insofar as a solid waste is a hazardous waste if it exhibits any one of four specific characteristics ignitability, reactivity, corrosivity, and toxicity. 

However, before a refinery can determine if its waste is hazardous, it must determine that the waste is indeed a solid waste. In 40 CFR 261.2, the definition of solid waste can be found. If a waste material is considered a solid waste, it may be a hazardous waste in accordance with 40 CFR 261.3. There are two ways to determine whether a waste is hazardous. These are to see if the waste is listed in the regulations or to test the waste to see if it exhibits one of the characteristics (40 CFR 261). 

The Resource Conservation and Recovery Act (RCRA) was enacted in 1976 and was revised substantially by the Hazardous and Solid Waste Amendment (HSWA) of 1984 (40 CFR pts. 260-280). The RCRA regulates the management of solid wastes that are hazardous. The definition of solid wastes in these regulations generally encompasses all discarded materials (including solid, liquid, semisolid, and contained gaseous materials) and many secondary materials (e.g., spent solvents, byproducts) that are recycled or reused rather than discarded [3]. Products such as commercial pesticides are not ordinarily solid wastes, but they become solid wastes if and when they are discarded or stored, treated, or transported prior to such disposal. 

The definition of solid waste in RCRA specifically excludes source, special nuclear, and byproduct materials as defined in AEA. Therefore, radioactive constituents of wastes that arise from operations of the nuclear fuel cycle are excluded from regulation as hazardous waste under RCRA. 

Given the definition of solid waste described above, Section 1004(5) of RCRA (1976) then defines hazardous waste as follows ... 

The United States EPA, in implementing RCRA, has further clarified and broadened the definition of solid waste in a series of definitions and sub-definitions [21,26], as follows ... 

EPA. 1985a. Identification and listing of hazardous waste. Definition of solid waste. U.S. Environmental Protection Agency. Code of Federal Regulations. 40 CFR 261.2. 

This definition of solid waste has caused great confusion. The expression and sometimes is discarded has led to ambiguities in deciding if a by-product which is reused by a segment of the regulated community and discarded by others is to be considered a solid waste. 

As this Chapter goes to press a new definition of solid waste and new standards for recycled hazardous wastes have been proposed. See 48FR 144T2, April 4, 1983. 

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