Influence of electron donor and toxic materials on the activity of sulfate reducing bacteria for the treatment of electroplating wastewater

Abstract

The effects of electron donor and toxic materials on the activity of SRB (sulfate reducing bacteria) were evaluated to ensure the efficient treatment of electroplating wastewater using an anaerobic batch test. The maximum utilization rate of glucose by SRB was slightly slower than that of lactate and acetate, but the affinity of glucose on the SRB was similar to that of the acetate and the lactate. The concentration of carbon source required to reduce 2,000mg/L of sulfate, that is the common concentration of sulfate in the raw electroplating wastewater, was estimated as about 2,200mg COD/L. The efficiency of carbon source for the reduction of sulfate was the highest at around 0.33 of the COD/SO4−2 ratio, but the rate of sulfate reduction was increased according to the increase of COD/SO4−2 ratio ranged from 0.18 to 1.21. Inhibition of copper on the activity of SRB was able to explain using non-competitive inhibition model, and IC50 for copper, that is the concentration causing 50% inhibition of SRB activity, was about 100mg/L of copper. The inhibition of chromium(VI) on the activity of SRB was observed as a mixed inhibition, but the degree of inhibition on the activity of SRB was only about 15% at 130mg/L of the chromium(VI). The inhibitory effect on the SRB caused by 10mg/L of cyanide compound was over 30% of the control, and it was rapidly increased with the cyanide concentration. That could be explained using uncompetitive inhibition model, and IC50 was estimated as about 20mg/L.