INFLUENCE OF SELECTOR TECHNOLOGY ON HEAVY-METAL REMOVAL BY ACTIVATED-SLUDGE - SECONDARY EFFECTS OF SELECTOR TECHNOLOGY

The purpose of this research is to compare the ability of metal remova l between an aerobic selector activated sludge system and a convention al CSTR system. Metal biosorption by sludge harvested from experimenta l systems was determined by a series of batch experiments. Heavy metal s studied in this research were zinc, cadmium and nickel. Results of e xperimental data revealed that metal biosorption by activated sludge w as rapid; about 70% of the soluble metals in solution was removed duri ng the first 30 min. The sorption isotherm showed that at metal equili brium concentrations greater than 0.05 mg/l, the selector sludge had s ignificantly higher sorption capacity than did the CSTR sludge. Metal biosorption behavior closely followed a Freudlich isotherm model for e quilibrium concentrations above 0.05 mg/l. Results of the Freundlich m odel suggested that the adsorption capacity of sludge from the aerobic selector was significantly higher than that of the CSTR system.