Mobility of Organic and Inorganic Constituents from Energy and Combustion-Related Wastes Under Codisposal Conditions

Abstract

AbstractThe criteria for determining toxicity of a solid waste under the Resource Conservation and Recovery Act (RCRA) are the levels of NIPOW contaminants as determined using the extraction procedure (EPA-EP). This procedure is predicated on a scenario of disposal of the solid waste in a municipal landfill, resulting in contact with an acidic leaching medium. The scenario includes a 95/5 municipal waste/industrial waste ratio. The experimental definition of the leaching rates of various contaminants under the conditions of this scenario is the object of this work.The experimental design included the use of large scale lysimeters (1.8 M in diameter × 3.6 M height) packed with 1.5 metric tons of municipal waste. A flow rate of -6.5 1/day of distilled water was added to the lysimeters for the generation of municipal waste leachate (MWL). The MWL was used to leach a variety of industrial wastes, including resource recovery ashes, an API separator sludge/incinerator ash mixture, and a coking plant wastewater treatment sludge. The resulting leachates were analyzed for both inorganic and organic constituents.Inorganic constituents showed two distinct types of leaching behavior. Freely soluble elements (B, Na, Ca, etc.) gave leaching curves which showed exponential declines. Acid-soluble elements (Ni, Zn) eluted as “peaks” as the pH of the leachate decreased. Organic constituents gave leaching curves which were dependent on solubility: either an exponential decline (freely soluble compounds) or a relatively flat curve at or near the solubility limit. The availability of this data base has allowed the development of a laboratory extraction procedure for the prediction of contaminant migration in municipal landfills.