Hazardous waste landfill

LandtiUing of Hazardous Wastes In many states, the only disposal option available for most hazardous wastes is landfilling. The basis for the management of hazardous-wastes landfills is set forth in the Resource Conservation and Recovery Act of 1976. In general, disposal sites for hazardous wastes shoiild be separate from sites for municipal solid wastes. If separate sites are not possible, great care must be taken to ensure that separate disposal operations are maintained. 

Requirements The requirements for a hazardous-waste landfill are detailed in RCRA and the regulations developed to implement the act. From a design standpoint, two of the most important requirements are (1) complete leachate containment, and (2) control of the surface water on and around the site. 

Many but not all hazardous wastes can be disposed of on land in properly designed landfills. To minimize potentially adverse environmental effects from wastes deposited at hazardous-waste landfill sites, the U.S. Environmental Protection Agency (EPA) has developed specific regulations regarding the characteristics of wastes suitable for landfilling. These regulations (40 CFR 265) include a prohibition on the placement of ... 

Veiy small containers, such as ampules, and containers holding liquids for use other than storage, such as batteries, which may be disposed directly in a hazardous-waste landfill. 

Likewise, fly ash from power plant combustors often contains small amounts of metals or their oxides, which require costly disposal in the ever-shrinking number of approved hazardous waste landfills. Thus, there are economic incentives to recover the metal values as well as to reduce the costs of ultimate disposal. Here, too, the metal content is low, and research is needed to develop economical separation processes. In principle, advances in this area could be translated into recovery of metal values from mine tailings. 

Air, soil, and water are vital to life on this planet. We mnst protect these resonrces and nse them wisely— onr snrvival as a species depends on them. Despite recent impressive strides in improving the environment, evidence is overwhelming that more effective action mnst be taken to address snch critical issnes as acid rain, hazardons waste disposal, hazardous waste landfills, and groundwater contamination. It is also vital that we assess realistically the potential health and enviromnental impacts of emerging chemical products and technologies. The problems are clearly complex and demand a broad array of new research initiatives. 

The exact composition and proportion of these additives in a certain type of fluid depends on the intended use. Hydraulic fluids are compounded to conform to performance-based standards such as Military or ASTM (American Society for Testing and Materials) specifications. Some examples of Military specifications are shown in Table 3-2. Many different formulations can be compounded to conform to one performance standard. It should be noted that the variability among these products or even within products with the same trade names may confuse efforts to determine environmental and health effects of hydraulic fluids at hazardous waste landfills since hydraulic fluids that are currently used may or may not contain the same components present in old products of the same name. 

Ghassemi, M., Quintara, S., and BachMare, J., Characteristics of leachates from hazardous waste landfills, J. Environ. Sci. Health. A, 19, 679-620, 1984. 

The site conditions for an on-site landfill, such as location, geology, hydrogeology, physiography, climate, and so on, should also be suitable. Landfill should meet the minimum technology requirements and regulations for hazardous waste landfills such as double liners and leachate collection and removal systems, leak detection systems, closure procedures and final cover, and construction quality assurance.59... 

There is some uncertainty about the potential presence of metal in the TCE-contaminated soil of Area 2. If metal concentrations of concern are present, only Alternatives 2 and 5 would protect against direct contact and further groundwater contamination through a cap and incineration, respectively. Incineration of metal-contaminated soil may result in a hazardous waste residue, which would have to be disposed of in a hazardous waste landfill. Alternatives 3 and 4 rely on vapor extraction and would not lower risks from metal to human health or the environment. 

Alternative final cover systems, such as the innovative evapotranspiration (ET) cover systems, are increasingly being considered for use at waste disposal sites, including municipal solid waste (MSW) and hazardous waste landfills when equivalent performance to conventional final cover systems can be demonstrated. Unlike conventional cover system designs that use materials with low hydraulic permeability (barrier layers) to minimize the downward migration of water from the cover to the waste (percolation), ET cover systems use water balance components to minimize percolation. These cover systems rely on the properties of soil to store water until it is either transpired through vegetation or evaporated from the soil surface. 

For hazardous waste landfills, RCRA Subtitle C provides certain performance criteria for final cover systems. While RCRA does not specify minimum design requirements, U.S. EPA has issued guidance for the minimum design of these final cover systems. Figure 25.1b shows an example of an RCRA Subtitle C cover at a hazardous waste landfill.30... 

FIGURE 25.1 Examples of final cover systems, (a) MSW landfill and (b) hazardous waste landfill.15... 

Hill Air Force Base, Ogden, UT Hazardous waste landfill Operational 1994... 

Uranium Mill Tailings Repository, UT (ACAP project) Hazardous waste landfill Operational July 2000... 

Warren, R.W., Hakonson, T.E., and Bostik, K.V., The hydrologic evaluation of four cover designs for hazardous waste landfills, in Landfill Capping in the Semi-Arid West Problems, Perspectives, and Solutions, Reynolds, T.D. and Morris, R.C., Eds, Environmental Science and Research Foundation, Idaho Falls, ID, 1997. 

U.S. EPA, Technical Guidance Document Final Covers on Hazardous Waste Landfills and Surface Impoundments, EPA/530-SW-89-047, U.S. Environmental Protection Agency, Washington, DC, July 1991. 

FIGURE 26.2 Double-liner designs. (Adapted from U.S. EPA, Requirements for Hazardous Waste Landfill Design, Construction, and Closure, EPA/625/4-89/022, U.S. Environmental Protection Agency, Cincinnati, OH, August 1989.)... 

The final component of the regulatory/guidance summary discusses the construction of a hazardous waste landfill. The following section summarizes U.S. EPA s CQA program.1314... 

Regulatory requirements for hazardous waste landfill double-liner systems are given in 40 CFR 264.3 The minimum liner system design standard generally considered to meet these requirements includes, from top to bottom4 ... 

Final cover systems are another important component of waste containment systems used at landfills. While liner systems are installed beneath the waste, final cover (or closure) systems are installed over the completed solid waste mass. For hazardous waste landfills, 40 CFR 264 requires that the landfill be closed with a final cover system that meets certain performance criteria, most notably, that they have a permeability less than or equal to the permeability of any bottom liner system or natural subsoils present. U.S. EPA guidance documents517 recommend that final cover systems for hazardous waste landfills consist of at least the following, from top to bottom ... 

This section discusses soil liners and their use in hazardous waste landfills. The section focuses primarily on hydraulic conductivity testing, both in the laboratory and in the field. It also covers materials used to construct soil liners, mechanisms of contaminant transport through soil liners, and the effects of chemicals and waste leachates on compacted soil liners. 

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