EFFECT OF AERATION, CADMIUM CONCENTRATION, AND SOLIDS CONTENT ON ACID EXTRACTION OF CADMIUM FROM A MUNICIPAL WASTEWATER SLUDGE.

Recent research has indicated that plant uptake of trace metals from land-applied sludge decreases as the sludge metal content decreases, and restrictions on the use of wastewater sludges because of metal concentrations could increase the feasibility of removing metals from high-metal sludges. While industrial pretreatment remains the most effective means of reducing metals in sludge, several studies have investigated the feasibility of removing metals from sludge. These have all involved acid extraction and most have used aerated or activated sludges. The experiments presented here used an anaerobically digested sludge high in Cd. The emphasis here is on the acid extraction process itself and the factors that affect Cd removal.