Definition Corrosivity, hazardous wastes

Potential environmental hazards from wastewater sludges are associated with trace constituents (e.g., chlorinated organic compounds) that partition from the effluent into the sludge. It should be noted, however, that recent trends away from elemental chlorine bleaching have reduced these hazards. A continuing concern is the very high pH (>12.5) of most residual wastes. When these wastes are disposed of in an aqueous form, they may meet the RCRA definition of a corrosive hazardous waste.24... 

Hazardous chemical waste is defined in RCRA regulations as a solid waste that exhibits the characteristic of ignitability, corrosivity, reactivity, or toxicity, or is a specifically listed waste. The definition of hazardous waste specifically excludes radioactive material (source, special nuclear, or byproduct material) defined in AEA. 

UK law imposes a system controlling the management of hazardous wastes, which places requirements on producers and carriers of the waste as well as owners and operators of storage and disposal facilities. There are many possible definitions of hazardous waste , but the term usually includes any solid, liquid or contained gas which is either ignitable, corrosive, reactive or toxic (or any combination of these) and which is at the end of its useful life. 

Hazardous Wastes The U.S. EPA has defined hazardous waste in RCRA regulations, CFR Parts 260 and 261. A waste may be hazardous if it exhibits one or more of the following characteristics (1) ignitability, (2) corrosivity, (3) reactivity, and (4) toxicity. A detailed definition of these terms was first published in the Federal Register on May 19, 1980, pages 33, 121-122. A waste may be hazardous if listed in Appendix Wll. 

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. 

There are four lists of hazardous wastes in the regulations wastes from nonspecific sources (F list), wastes from specific sources (K list), acutely toxic wastes (P list), and toxic wastes (U list) there are also the four characteristics mentioned before ignitability, corrosivity, reactivity, and extraction procedure toxicity. Certain waste materials are excluded from regulation under the RCRA. The various definitions and situations that allow waste to be exempted can be confusing and difficult to interpret. One such case is the interpretation of the mixture and derived-from rules. According to the mixture rule, mixtures of solid waste and listed hazardous wastes are, by definition, considered hazardous. Similarly, the derived-from rule defines solid waste resulting from the management of hazardous waste to be hazardous (40 CFR 261.3a and 40 CFR 261.1c). 

This definition is further amplified by Section 3001(a) of RCRA (1976), which specifies that EPA shall develop and promulgate criteria for identifying the characteristics of hazardous waste and for listing hazardous waste, taking into account its toxicity, persistence, and degradability in nature, potential for accumulation in tissue, and other related factors such as flammability, corrosiveness, and other hazardous characteristics. 

Operationally, a waste is classified as hazardous based on three criteria (1) it is listed as a hazardous waste (40 CFR 261 subpart D) (2) it has one of the following four characteristics ignitability, corrosivity, reactivity, and toxicity (see 40 CFR 261 subpart C for the specific definition of these characteristics) or (3) it falls into the category of "other" hazardous waste (primarily mixtures of non-hazardous materials with hazardous waste). 

N.B., this value is of particular significance in the USA, where the definition of hazardous corrosive wastes specifically excludes lime sludges, by defining a liquid as hazardous when it has a pH of 12.5, or greater, at the standard reference temperature of 25 °C.)... 

For solid wastes to warrant management as hazardous wastes, they must meet one of four characteristics (flammability, corrosivity, reactivity, and toxicity) or be listed on one of four lists, although some otherwise hazardous wastes by these definitions are excluded. Hazardous wastes carry one or more identifying waste codes four digits comprised of a letter (D, F, K, P, or U) followed by three numbers. For example, a flammable hazardous waste, possibly waste naphtha, carries the waste code DOOL... 

Hazardous wastes are either listed wastes (40 CFR 261.30-.33) or characteristic wastes (40 CFR 261.21-.24). The U.S. EPA defines four characteristics for hazardous waste ignitability (40 CFR 260.21) corrosivity (40 CFR 260.22) reactivity (40 CFR 260.23) and toxicity (40 CFR 260.24). Any waste that exhibits one or more of these characteristics is classified as hazardous under RCRA. The ignitability definition includes a liquid that has a flash point less than 60 C (140 F) the EPA included ignitability to identify wastes that could cause fires during transport, storage, or disposal (e.g., used solvents). All of the solvents in Table 14.10.5 have flashpoints less than 60 C, so all could be a RCRA ignitability waste. 

Because the EPA regulates hazardous wastes in order to protect the environment (not to prevent human exposures), they define hazardous properties differently than agencies such as OSHA, whose purpose is to protect humans. According to the EPA, hazardous waste is chemical material that has been or will be discarded and it has one or more hazardous characteristics or is on one of four lists (called F, K, P, and U Lists). The characteristics regulated are flammability, corrosivity, reactivity, or toxicity. Toxicity is defined as a liquid with concentrations above those listed on the Toxicity Characteristic Leaching Procedure (TCLP) list or< > a solid that when extracted by the TCLP, has a resultant concentration about listed concentrations. This definition has little to do with the human exposure definition of toxicity that you will find in the toxicology sections of this book. 

All nonproduct hazardous outputs into all environmental media, even though they may be within permitted or licensed limits. This is much broader than the legal definition of hazardous solid waste in the Resource Conversation and Recovery Act, its amendments, and subsequent regulations. Hazardous refers to harm to human health or the environment as is broader than the term toxicity. For example, wastes that are hazardous because of their corrosive, flammability, explosiveness, or infectiousness are not normally considered toxic. [p. 31]... 

Wastes are considered hazardous according to the Resource Conservation and Recovery Act (RCRA) when they meet one or more criteria including ignitability, corrosivity, reactivity or toxicity as per EPA definitions (see Glossary of Terms). Additionally, wastes are also considered hazardous when they are included in one of the following lists ... 

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