Hazardous waste corrosivity

Pumps for Corrosive or Toxic Applications. For some appHcations, pumpage is not only severely corrosive but also toxic, so that the pumpage must be contained with 2ero leakage (see Waste tee atment, hazardous wastes). One possibiHty is to employ a magnetically driven pump having a nonmetaUic, usually Teflon, liner at the Hquid end. 

A sohd waste is considered hazardous if it is either a Hsted waste or a characteristic waste. Listed wastes include a Hst of specific processes that generate a waste and a Hst of discarded commercial chemical products. There are four hazardous waste characteristics ignitabiHty, corrosivity, reactivity, and toxicity. The last refers to the leachabiHty of a waste and the resultant toxicity in the groundwater using the analytical method referred to as toxicity characteristic leaching procedure (TCLP). A Hst of substances included under TCLP is shown in Table 1. 

Under the Comprehensive Environmental Response, Compensation, and LiabiHty Act (CERCLA)/RCRA regulations in effect at the end of 1986 bromine is regulated as a hazardous waste or material. Therefore, it must be disposed of in an approved hazardous waste faciHty in compliance with EPA and/or other appHcable local, state, and federal regulations and should be handled in a manner acceptable to good waste management practice. The reportable quantity is 45.4 kg for corrosivity (62). 

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. 

In the past, hazardous wastes were often grouped into the following categories (1) radioactive substances, (2) chemicals, (3) biological wastes, (4) flammable wastes, and (5) explosives. The chemical cate-goiy included wastes that were corrosive, reactive, and toxic. The principal sources of hazardous biological wastes are hospitals and biological-research facilities. 

It is unusual to find a hazardous-waste-transfer facility at which wastes are simply transferred to larger transport vehicles. Some processing and storage facihties are often part of the materials-handliug sequence at a transfer sec tion. For example, neutralization of corrosive wastes will resiilt in the use of lower-cost holding tanks on transport vehicles. 

The testing of chemicals/wastes to establish the nature of their hazard capacity/threat in accordance with regulatory requirements falls into four categories (1) reactivity, (2) ignitability/flammability, (3) corrosivity, and (4) EP toxicity. Commercial chemical products, specific wastes, and wastes from specific processes may be listed as hazardous wastes because they are known to present toxic hazards in the manner of the tests above and/or are known to present serious toxic hazards to mammals/humans. In the discussion to follow, various chemical groups will be examined primarily in the context of reactivity, ignitability, and corrosivity. 

Notification to the NRC is required for releases equal to or greater than the reportable quantity of a RCRA hazardous waste. If the waste also is on the CERCLA list, that reportable quantity applies. If not, the reportable quantity is 100 pounds if the waste is ignitable, corrosive, reactive, or toxic. 

Soil Cleanup, or remediation, of hazardous waste sites will often produce contaminated soil. Contaminated soil must be handled as hazardous waste if it contains a listed hazardous waste or if it exhibits a characteristic of hazardous waste. As with hazardous waste, land disposal of hazardous soil is prohibited until the soil has been treated to meet LDR standards. These contaminated soils, due to either their large volume or unique properties, are not always amenable to the waste codespecific treatment standards. Because of this, U.S. EPA promulgated alternative soil treatment standards in 268.49 in May 1998. The alternative soil treatment standards mandate reduction of hazardous constituents in the soil by 90% or 10 times UTS, whichever is higher. Removal of the characteristic is also required if the soil is ignitable, corrosive, or reactive. 

The waste typically exhibits one of the four characteristics of hazardous waste described in the hazardous waste identification regulations (ignitability, corrosivity, reactivity, or toxicity). 

Corrosive wastes are acidic or alkaline (basic) wastes which can readily corrode or dissolve flesh, metal, or other materials. They are also among the most common hazardous wastestreams. Waste sulfuric acid from automotive batteries is an example of a corrosive waste. U.S. EPA uses two criteria to identify corrosive hazardous wastes. The first is a pH test. Aqueous wastes with a pH greater than or equal to 12.5, or less than or equal to 2 are corrosive under U.S. EPA s rules. A waste may also be corrosive if it has the ability to corrode steel in a specific U.S. EPA-approved test protocol. 

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... 

A waste is a hazardous waste if it is listed or is identified for ignitability, corrosivity, or both. 

The physical properties of lead and several of its compounds are listed in Table 3-2. Lead readily tarnishes in the atmosphere but is one of the most stable fabricated metals because of its corrosive resistance to air, water, and soil (Howe 1981). A waste that contains lead or lead compounds may (or may not) be characterized a hazardous waste following testing by the Toxicity Characteristic Leaching Procedure (TCLP) as prescribed by the Resource Conservation and Recovery Act (RCRA) regulations. 

Under the authority of the RCRA, a solid waste would be defined as hazardous if it exhibits any of the four (ignitability, corrosivity, reactivity, and toxicity) characteristics used to identify hazardous wastes. 

WASTE DISPOSAL METHOD Disposal methods for waste DS2 and accumulated spill cleanup residues must comply with RCRA, state, and local hazardous waste regulations and procedures. If the wastes are corrosive, they have the EPA Hazardous Waste Number... 

The liquid effluent, which consists of water from the evaporator/crystallizer used to produce the solid filter cake produced by the brine-recovery operation, should not pose a significant hazard to human health or to the environment. While the evaporator/crystallizer system has not been tested yet, the composition of the water and solid filter cake can be readily determined from an analysis of the SCWO liquid effluent. As shown in Table 5-10, the liquid effluent is essentially free of organics. The source of the chromium and nickel that were found in some of the effluents is generally believed to be corrosion products from the SCWO reactor components. These elevated levels of metals indicate that the solid filter cake will need to be treated (e.g., by stabilization) prior to disposal in a hazardous waste landfill. 7... 

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. 

Corrosivity. A liquid waste that has a pH of less than or equal to 2 or greater than or equal to 12.5 is considered to be a corrosive hazardous waste (40 CFR 261.22). Sodium hydroxide, a caustic solution with a high pH, is often used... 

Reactivity. A material is considered to be a reactive hazardous waste if it is normally unstable, reacts violently with water, generates toxic gases when exposed to water or corrosive materials, or if it is capable of detonation or explosion when exposed to heat or a flame (40 CFR 261.23). Materials that are defined as forbidden explosives or class A or B explosives by the Department of Transportation are also considered reactive hazardous waste. 

The first step to be taken by a generator of waste is to determine whether that waste is hazardous. Waste may be hazardous by being listed in the regulations, or by meeting any of four characteristics ignitability, corrosivity, reactivity, and extraction procedure (EP) 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). 

A waste stream may be defined as hazardous under RCRA if it meets certain criteria for ignitability, corrosivity, reactivity, or toxicity, or if the waste stream is specifically identified by EPA as a hazardous waste. An individual waste stream is subject to being classified as hazardous (listed) if it contains any one of approximately 375 chemicals identified by EPA as hazardous constituents. These designated chemicals are frequently referred to as Appendix Vlll compounds because of where they are listed in the published regulation. 

The hazardous waste identification regulations that define the characteristics of toxicity, ignitability, corrosivity, reactivity, and the tests for these characteristics, differ from state to state. In addition, concentration limits may be set out by a state for selected persistent and bioaccumulative toxic substances that commonly occur in hazardous substances. For example, the California Hazardous Waste Control Act requires the California State Department of Health Services (CDHS) to develop and adopt by regulation criteria and guidelines for the identification of hazardous wastes and extremely hazardous wastes. 

California criteria for defining hazardous wastes that are ignitable and reactive are identical to Federal criteria for hazardous wastes under RCRA defined at 40 CFR, Part 261. The California corrosivity criteria differ from the Federal criteria only in the addition of a pH test for nonaqueous wastes. 

Household Hazardous Waste (HHW) is defined by the U.S. EPA as solid wastes, discarded from homes or similar sources, that are either hazardous wastes or wastes that exhibit any of the following characteristics ignitabiUty, corrosivity, reactivity, or toxicity. A significant fraction of HHW is generated by home mechanics who use such products as motor oil, cleaners and solvents, refrigerants, and batteries. The results indicate that most of the survey respondents perceive automotive products to pose significant health and environmental risks, and they tend to dispose of these wastes in an environmentally conscious manner. There is qnite often a discrepancy between human perception and scientific reality (see table 8.2) (Shorten et al., 1995). 

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