Copper Removal by Biofilms

A laboratory scale biofilm reactor will be used to develop biofilm growth on sampling slides by introducing a synthetic feed with a designed COD and copper concentration.The threshold of copper sorption will be determined by measuring the total copper and free copper in the influent, effluent, EPS and biofilms.The surface charge of the biofilm, and the amount of extracellular polysaccharides, extracellular proteins, and uronic acids within the biofilms will be determined to establish the cellular response to copper contamination for concentrations of 100ppb and 200ppb.The COD concentration of the synthetic feed will be adjusted for each of the two copper concentrations to determine the effect of substrate concentration on copper removal.It is believed that microorganisms can sorb positively charged heavy metals by producing negatively charged extracellular polymeric substances (EPS).EPS is comprised of extracellular proteins containing negatively charged amino acids and numerous polyanionic extracellular polysaccharides.A negative surface develops on the EPS, which subsequently provides metal binding sites.However, the presence of heavy metals may influence cellular production of EPS.