BALANCE OF HEAVY-METALS THROUGH A SEWAGE-TREATMENT WORKS .2. CHROMIUM, NICKEL AND ZINC

Concentrations of chromium, nickel and zinc have been determined in the sewage sludges, sewages and effluent of a sewage-treatment works. Treatment at this works is by primary sedimentation prior to biological treatment in a diffused air activated sludge plant. By analysis of composite samples corresponding to a 24-h input of raw sewage to the works, a mass balance of these metals through the works has been estimated. The partition of these metals from raw sewage into settled sewage and primary sludge, and from the settled sewage into the activated sludge and final effluent has been quantified. © 1979.