Remediation of heavy metal pollution by sulfate reducing bacteria (SRB) isolated from activated sludge in lead-zinc smelter slag

Abstract:

[Background] A group of microorganisms with sulfate reduction ability were isolated from activated sludge, and their feasibility of heavy metal pollution remediation of lead-zinc smelter slag was also explored. [Objective] To study the solidification of heavy metals in lead-zinc smelter slag by sulfate reducing bacteria (SRB) obtained. [Methods] Sulfate-reducing bacteria isolated from activated sludge were inoculated into lead-zinc smelting slag for remediation. X-ray diffraction, Tessier, inductively coupled plasma optical emission spectrometer and high-throughput sequencing techniques were used in remediation experiments. The mineral composition of lead-zinc smelter slag, the chemical fractions of heavy metals, the concentration of metal ions and the structure of microbial community were detected during the remediation process. [Results] The results of remediation experiments showed that the redox potential decreased, the pH increased, the stable state of heavy metals increased, the ion concentration decreased and the microbial community structure changed significantly. Sulfate reducing bacteria became the main microbial community. [Conclusions] By inoculating sulfate reducing bacteria into lead-zinc smelter slag, the heavy metals could be solidified in situ significantly, thus reducing the bioavailability and improving environment. Sulfate reducing bacteria can be used as solidifying agents for remediation of heavy metal contaminated sites.