The report describes progress made on a field evaluation project being conducted by the EPA to assess techniques for disposing of power plant flue gas cleaning (FGC) wastes. The evaluation site is at TVA's Shawnee steam plant in Paducah, KY. Two prototype scrubbers, using lime and limestone absorbents and rated at 10 MWe, produced the sludges used in the project. By mid-1978, eight ponds were being evaluated: two untreated, three chemically treated, and three untreated with underdrainage. One underdrained pond contains sulfite sludge which has been oxidized to sulfate (gypsum). Groundwater, supernate, leachate, underdrain, runoff, and sludge and soil cores are being analyzed. After 3 years, the wastes in two of the chemically treated ponds and the untreated ponds with underdrainage are exhibiting the ability to shed water and to control seepage, respectively, and to support construction vehicles. The chemically treated pond under water reduces sludge permeability by about 1 order of magnitude as do the others, and provides strength but not traction for vehicles. Gypsum dewaters and handles easily, but its runoff and leachate must be controlled to prevent discharge to water supplies. It becomes structurally unstable when rewet; however, the disposal site can be managed to prevent these conditions.

"Industrial Environmental Research Laboratory, Office of Environmental Engineering and Technology, Research Triangle Park, N.C." Jan. 1980. "Contract no. 68-02-2633, program element no. EHE624A." Includes bibliographical references.