STIMULATION OF ACTIVATED-SLUDGE CULTURES FOR ENHANCED HEAVY-METAL REMOVAL

The objective of this research was to investigate the feasibility of developing improved activated sludge cultures capable of removing heavy metals present in high concentrations. Bacterial acclimation and stimulation with special chemicals were employed to this end. Thus, cystine, peptone, and beta-glycerophosphate stimulated heavy metal uptake without a drastic reduction in culture viability otherwise experienced in the absence of these special nutrients. Acclimated-stimulated cultures substantially increased metal removal capabilities of aerobic cultures probably because of enhanced synthesis of metal-complexing biopolymers in the presence of precursor chemicals. The lethal effect of heavy metals could also be reduced significantly by culture development in the presence of these nutrients. The peptone-grown culture exhibited the highest removal of copper and cadmium of 0.65 and 0.68 mg/mg protein, respectively. This research shows that substantial improvements in the metal uptake capabilities of activated sludge cultures may be effected by including special nutrients (precursor biochemicals) with the process feed.