As required by the 1984 Hazardous and Solid Waste Act, EPA began a program to conduct in-depth evaluations of all hazardous wastes to determine applicable restrictions on some or all forms of land disposal. Under Section 3004(m) of the amendments, the EPA was required to develop treatment standards for wastes banned from land disposal. The waste streams that were identified as candidates for the Land-Ban Regulations included solvents, dioxin-containing wastes, halogenated organics, corrosives, metals, cyanides, and other reactives.
This paper presents an overall summary of three field sampling programs conducted by Alliance Technologies Corporation to assess the performance capabilities of offsite solvent recycling facilities. This work was performed under contract to the EPA's Hazardous Waste Engineering Research Laboratory (HWERL) in Cincinnati, OH (Contract 68-03-3243). These field programs resulted in the compilation of extensive data on the operation and performance capability of such waste treatment processes as steam distillation, thin-film evaporation, and still-bottom processing. Samples were taken of all waste feed, still bottoms, and distillate product streams and analyzed for inorganic and organic constituents to satisfy EPA criteria. Analytical results were evaluated to determine the fate of various metals and other solvent constituents among input and effluent streams. The suitability of some of these still-bottom streams for subsequent land-based disposal was addressed by determining characteristics such as EP-Toxicity for metals and the newly proposed Toxicity Characteristic Leaching Procedure (TCLP). Ultimately, each site tested was described in a comprehensive report that delineated all results and procedures used. These reports have become part of the EPA's database to support any treatment standards developed by the Agency.
In general, these field programs have shown that the solvent recycling processes evaluated are very effective in producing high-quality distillate product streams suitable for a variety of uses. In addition, metal contaminants detected in waste feed streams were virtually all transferred to the still-bottoms streams, which were mostly disposed of by offsite fuel supplement users (i.e., asphalt kilns and blast furnaces).