Removal of cadmium by microorganisms in a two-stage chemostat.

A two-stage chemostat was used to study removal of cadmium by microorganisms in continuous culture. The medium was contaminated with 0.8 mg of Cd per liter. At 20 degrees C, most of the microbial biomass formed aggregates which settled in the second stage of the chemostat. Effluent was free of bacteria. Up to 80% of the metal contained in the inlet flux was removed by the biomass, with 20% remaining in solution. At 10 degrees C and with a shorter retention time, flocculation was poorer and metal removal by settling biomass did not exceed 35%.