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

The objective of this research was to investigate the feasibility of d eveloping improved activated sludge cultures capable of removing heavy metals present in high concentrations. Bacterial acclimation and stim ulation with special chemicals were employed to this end. Thus, cystin e, peptone, and beta-glycerophosphate stimulated heavy metal uptake wi thout a drastic reduction in culture viability otherwise experienced i n the absence of these special nutrients. Acclimated-stimulated cultur es substantially increased metal removal capabilities of aerobic cultu res probably because of enhanced synthesis of metal-complexing biopoly mers in the presence of precursor chemicals. The lethal effect of heav y 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 prote in, respectively. This research shows that substantial improvements in the metal uptake capabilities of activated sludge cultures may be eff ected by including special nutrients (precursor biochemicals) with the process feed.