Enhanced biotreatment of acid mine drainage in the presence of zero-valent iron and zero-valent copper

Biaosheng Lin,Fengqing Gao,Xiaobing Hu

doi:10.2166/wrd.2018.014

Abstract

Abstract Batch laboratorial experiments were conducted to evaluate the potential of Fe0, Cu0 and sulfate-reducing bacteria (SRB) for reduction and removal of sulfate and heavy metals from synthetic acid mine drainage. The variation in solution pH indicates that the Fe0/Cu0 bimetallic system provided favorable conditions for SRB growth and sulfate reduction. When the SO42− concentration of wastewater was 3,000 mg/L, the SO42− removal efficiency was 51.6% for the SRB system, 76.3% for the Fe + SRB system, and 92.0% for the Fe/Cu + SRB system. Moreover, Pb2+, Cu2+ and Zn2+ ions were completely removed. The results demonstrate that the Fe/Cu + SRB system had apparent advantages over the SRB system, especially at low pH. This study demonstrates that an Fe/Cu + SRB system could be a promising technology for treating wastewater containing high concentrations of sulfate and heavy metals.

Highlights

Acid mine drainage (AMD), generated by the biological oxidation of metal sulfides to metal sulfates in mine wastes, is characterized by low pH and high concentrations of dissolved metals and sulfates (Peng et al )
The sulfates can be reduced to sulfides by sulfate-reducing bacteria (SRB) under anaerobic conditions, leading to air pollution and corrosion of metal pipes
Sulfates are non-toxic to organisms, but their reduction products have a highly poisonous effect on microbes including SRB (Singh et al )

Summary

INTRODUCTION

Acid mine drainage (AMD), generated by the biological oxidation of metal sulfides to metal sulfates in mine wastes, is characterized by low pH and high concentrations of dissolved metals and sulfates (Peng et al ). The sulfates can be reduced to sulfides by sulfate-reducing bacteria (SRB) under anaerobic conditions, leading to air pollution and corrosion of metal pipes. Biological processes have been employed as an alternative to treat sulfate-containing wastewater (Singh et al ; Rodriguez et al ). Sulfates are non-toxic to organisms, but their reduction products (namely sulfides) have a highly poisonous effect on microbes including SRB (Singh et al ). Fe0 packed anaerobic bioreactors have been developed to improve the treatment performance of sulfate-containing wastewater, resulting in better sulfate reduction and metal removal (Singh et al ; Zhang et al ; Ayala-Parra et al ). The validity and applicability of the system is tested and compared under different conditions

MATERIALS AND METHODS

Experimental procedures

Analysis methods

RESULTS AND DISCUSSION

CONCLUSIONS