Passive treatment of acid mine drainage with sulphate reducing bacteria

Abstract

This research was completed to assess passive treatment methods for mitigation of acid mine drainage (AMD) at a former mine site in British Columbia. The objectives were to determine if suitable passive treatment methods were available, and if concentrations of Cd, Zn, and other key contaminants in groundwater could be reduced to below regulatory standards during bench-scale testing. Biological treatment with sulphate reducing bacteria (SRB) was selected, and bench-scale treatment testing was conducted using columns amended with low cost organic sources. Removal of more than 99% Cd, 93% Co, 96 % Cu, 86% Ni and 98% Zn was observed, resulting in metals concentrations in treated effluent consistently lower than applicable groundwater standards. Sustainability attributes of treatment with SRB and the potential to recover valuable metals are discussed, and recommendations for further testing and implementation are provided.