The report, the second in a series of economic evaluations of flue gas desulfurization (FGD) waste disposal systems, gives results of a study of two processes that produce a soil-like landfill material without using purchased additives: (1) separately collected flyash is blended with dewatered FGD sludge from a limestone scrubbing system; and (2) air-oxidation modifications to a limestone scrubber, which also collects the flyash, produce a high-sulfate sludge (gypsum) which is dewatered and discarded without further treatment. Both processes are being developed; neither has been fully demonstrated. The sludge/flyash blending process had a higher capital investment ($36.40/kW) than the other (as well as untreated ponding and three of four chemical processes evaluated in an earlier study) primarily because of high electrostatic precipitator and process equipment costs; however, the process had lower annual revenue requirements (1.64 mills/kWh) than three of the four chemical processes. The gypsum process had the lowest capital investment ($15.40/kW) of all processes studied to date because of lower process equipment cost and higher waste bulk density; its annual revenue requirements (1.18 mills/kWh) were lower than all processes studied except untreated ponding. Capital investment costs are for mid-1979; annual revenue requirements are for mid-1980.

"February 1979." "EPA/600-7-79-069." Includes bibliographical references. "EPA interagency agreement D8-E721-B1, program element no. INE624A."