Biofilm concentration of chromium

Removal of chromium from synthetic waste streams was studied using biofilms that developed on disks of a laboratory scale Rotating Biodisk Contactor (RBC). During its development the biofilm was continuously exposed to various concentrations of potassium dichromate. Chromium removal efficiency was about 98% during steady state addition of chromium (VI) at concentrations of 100 or 200 mg l‐1. Analysis of the major soluble chromium ions demonstrated that chromium (VI) was first reduced to chromium (III) which then appeared to be adsorbed by the biofilm. Chromium levels associated with the biofilm were found (by chemical analysis) to be 6.5–7.0% of its dried weight.