THE INFLUENCE OF CADMIUM ON ACTIVATED-SLUDGE ACTIVITY

The influence of solid retention time, cadmium loading and the effect of the process of acclimation on the activity of activated sludge ill the presence of the metal were studied. Activated sludge was cultivate d in plug-flow and continuous completely mixed lab-scale bioreactors. Respisometric measurements were applied to evaluate the inhibition eff ects of cadmium on activated sludge. Monod's equation and the equation of noncompetitive inbibition were applied to describe the toxicity an d inhibition of cadmium. Maximum inhibition effect of cadmium was obse rved at different time periods of cadmium acting on both acclimated an d nonacclimated sludges. The dependence of the attainment of maximum i nhibition effect on the metal loading as well as solid retention time was observed. Therefore, maximum inhibition should be included in the assessment of metal toxicity.