Lead removal enhancement by an indigenous consortium of sulfate-reducing bacteria cultivated from the lead-contaminated wastewate

Abstract

Biological production of sulfide using sulfate-reducing bacteria (SRB) and high affinity of sulfide to react with divalent metallic cations have important potential in treatment of heavy metal contaminated wastewater. The feed COD/SO₄^2- ratio is an important parameter has been proposed to control the hydrogen sulfide production by SRB. The effect of the feed COD/SO₄^2- ratio on the sulfide production and removal of dissolved lead of a consortium of sulfate-reducing bacteria (DM10) cultivated from Dong Mai, Hung Yen was investigated in this study. The results showed that among 11 investigated consortiums, DM10 has highest tolerant capacities for lead. A maximum sulfide concentration of 425-456 mg/l was observed at a feed COD/SO₄^2- ratio of 3, with sulfate conversions of 91-92% after 6 days. The DM10 was able to remove up to 98-100% of the initial dissolved lead (50 and 100 mg/l) with a feed COD/SO₄^2- ratio of 2 and 3.

Keywords: Lead contaminated wastewater, lead precipitation, sulfate removal, sulfate-reducing bacteria, sulfide production