Twenty-eight lime stabilization facilities were visited. None of these plants were originally designed for sludge lime stabilization. Lime stabilization was instituted either as a permanent sludge handling mechanism to replace a more costly process, as an interim sludge handling technique, as a back-up process, or as a seasonal practice. Three general techniques of lime stabilization were observed. Lime addition to a liquid sludge before land application. Lime addition to a liquid sludge before cake dewatering. Lime addition to a dewatered sludge cake. Bacterial analyses performed at some of the facilities demonstrate that liming a sludge to a pH of 12 is an effective means of total and fecal coliform inactivation. The lime stabilized sludge product is either landfilled, land applied as a liquid sludge, applied to land as a cake, or stockpiled prior to landfilling or land application. Stockpiling of sludge has in some cases resulted in odors upon pile breakdown. Indications are that with pH drop in stockpiles regrowth of organisms can occur. Lime stabilized liquid sludge and cake sludge are land applied to farms and to test areas. According to operators at several facilities, farmers willingly accept the product reporting reduced soil liming requirements and satisfactory crop growth. Despite this, some facilities encountered difficulties in acquiring suitable land application sites.

"PB81-198160." "EPA 600-2-82-076."