Treatment of Hazardous Wastes

Membrane processes have many plications in the treatment of contaminated waste streams. The most common applications involve the removal and concentration of organic and inorganic contaminants from liquid waste streams. The waste steams can originate from industrial processes, contaminated groundwater, contaminated surface water bodies, or as by-products of other treatment processes. 

Membrane and filtration processes have historically been utilized for the treatment and purification of drinking water. For this application, filtration is used to remove a wide variety of constituents, ranging from visible particulates (sand filters, refer to Chapter 5) to ionic species (reverse osmosis, refer to Chapter 4). From these conventional applications, new uses of membrane separations have recently been applied to the treatment of hazardous waste streams. 

Containment and/or remediation of contaminated aquifers typically utilizes pump and treat technologies to control contaminant plume migration and ultimately restore the 

The contaminants of concern can be isolated and concentrated into a reduced volume which can be more easily handled. Another potential benefit of the concentration process is that additional destructive treatment alternatives may become feasible. For example, the concentration of hydrocarbons from a contaminated groundwater can produce a reduced volume waste with a high BTU value allowing for fuel blending as a disposal alternative. This not only reduces the quantity of groundwater that must be treated, but also produces a more easily treatable final waste product. As another example, heavy metals can be concentrated from an aqueous stream by membrane processes and immobilized by solidification/stabilization technologies. 

Membrane processes can be potentially used to recover organic and inorganic constituents for recycle/reuse. In these applications, the separation scheme must be developed to produce a high quality concentrate. 

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Aeration basins can be constmcted as concrete or steel tanks or earthen impoundments, although tanks are more common in the United States now because of ground water problems with leakage from impoundments and stringent regulation of impoundments for the treatment of hazardous waste. 

Adsorption — An important physico-chemical phenomenon used in treatment of hazardous wastes or in predicting the behavior of hazardous materials in natural systems is adsorption. Adsorption is the concentration or accumulation of substances at a surface or interface between media. Hazardous materials are often removed from water or air by adsorption onto activated carbon. Adsorption of organic hazardous materials onto soils or sediments is an important factor affecting their mobility in the environment. Adsorption may be predicted by use of a number of equations most commonly relating the concentration of a chemical at the surface or interface to the concentration in air or in solution, at equilibrium. These equations may be solved graphically using laboratory data to plot "isotherms." The most common application of adsorption is for the removal of organic compounds from water by activated carbon. 

Solidification/Stabilization technologies are techniques designed to be used as final waste treatment. A major role of these processes is posttreatment of residuals produced by other processes such as incineration or chemical treatment. In some cases, solidification/ stabilization processes can serve as the principal treatment of hazardous wastes for which other detoxification techniques are not appropriate. High volume, low toxicity wastes (such as contaminated soils) are an example of this application. 

Chaney R.L. Potential effects of waste constituents on the food chain. In Land Treatment of Hazardous Wastes, Parr J.F., ed. Park Ridge, New Jersey Noyes Data Corp, 1983. 

Mondello F.J., D.A. Abramowicz, J.R. Rhea, Natural Restoration of PCB-Contaminate Hudson River Sediments in Biological Treatment of Hazardous Wastes, (1998), John Wiley Sons, pp.303-326. 

Johanson, J. G. Yosim, S. J. Kellogg, L. G. Sudar, S. "Elimination of Hazardous Wastes by the Molten Salt Destruction Process," Proc. 8th Annu. Res. Symp. Incineration and Treatment of Hazardous Waste, EPA-600/9-83-003,... 

Egg, R.P. Redell, D.L. Avant, R. In "Treatment of Hazardous Waste Proceedings of the 6th Annual Research Symposium" Shultz, D., Ed. PB80-175094, National Technical Information Service Springfield, VA, 1980 pp. 88-93. 

Cases When Biotechnology is Most Applicable for the Treatment of Hazardous Wastes... 

Several key factors are critical for the successful application of biotechnology for the treatment of hazardous wastes (a) environmental factors, such as pH, temperature, and dissolved oxygen concentration, must be optimized (b) contaminants and nutrients must be available for action or assimilation by microorganisms (c) content and activity of essential microorganisms in the treated waste must be sufficient for the treatment. 

J. W. Blackburn. 1988. Problems in and potential for biological treatment of hazardous wastes. Proc. 81st Annual AWMA Meeting. Air and Waste Management Assodatioa Pittsburgh. 

Cesium hydroxide is used as electrolyte in alkahne storage batteries. Other apphcations of this compound involve catalytic use in polymerization of cyclic siloxane and treatment of hazardous wastes. 

Cement-based stabiUzation/solidification (S/S) is a technology for the in situ or ex situ treatment of hazardous wastes and hazardous waste sites. It is a process that uses cement and other additives or processes to physically and/or chemically immobilize the hazardous constituents of contaminated soils, sludges, sediments, or liquid wastes. The objective is to prevent the migration of contaminants in the environment by forming a solid mass. 

EM C Engineering Associates markets the Vitriflux vitrification system for the treatment of hazardous wastes. The vendor claims that the unique feature of this vitrification system is that fluxing material is added to achieve vitrification at relatively low temperatures. Although this technology has only been tested as an ex situ process, the developer claims that in situ treatment is possible. 

OnSite Technology, L.L.C. (OnSite) has developed the portable indirect thermal desorption (ITD) system for the treatment of hazardous wastes. The ITD 6000 uses a rotating, heat-jacketed closed barrel to vaporize hydrocarbons from contaminated soils and drilling mud, allowing the hydrocarbons to be recovered while cleaning the contaminated sediment. The technology is commercially available. 

Refranco Corporation (Refranco) has developed sustained shock thermal plasma (SSP) technology for the ex situ treatment of hazardous wastes. The technology uses a combination of electrodes to form a nonequUibrium plasma that distributes the thermal load between the waste particles during treatment. A commercial pilot facility treat municipal solid waste, ashes, oil, and sewage sludge has been built in Singapore. The technology is commercially available. 

Itkonen, A. O. Jantunen, M. J. 1989. The properties of fly ash and fly ash mutagenicity. In Cheremisinoff, P. N. (ed) Encyclopedia of Environmental Control Technology. Volume 1 Thermal Treatment of Hazardous Wastes. Butter-worth-Heinemann, Burlington, MA. 

Nadim, L., Schocken, M.J., Higson, F.J., Gibson, D. T., Bedard, D. L., Bopp, L. H. Mondello, F. J. (1987). Bacterial oxidation of polychlorinated biphenyls. In Proceedings of the 13th Annual Research Symposium on Land Disposal, Remedial Action, Incineration, and Treatment of Hazardous Waste, pp. 395—402. U.S. Environmental Protection Agency, Cincinnati, OH (EPA/600/9-87/015). 

Requires incineration or equivalent treatment of hazardous wastes with greater than 3000 Btu/lb. Existing law becomes effective postponed to 1990. 

Membrane Separation Processes for Treatment of Hazardous Waste... 

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