Electro-biochemical reactor (EBR) technology for selenium removal from British Columbia’s coal-mining waste waters
Minerals & Metallurgical Processing
, 2014, Vol. 31, No. 4, pp. 209-214
Opara, A.; Peoples, M.J.; Adams, D.J.; Martin, A.J.
The weathering of coal mine waste rock releases iron, calcium, sulfate and associated trace elements like selenium (Se). Nitrogen species are also found in association with coal-mining drainages mainly due to the leaching of residual blasting compounds. Elevated concentrations of Se are a ubiquitous occurrence in coal-mining environments in British Columbia. A major concern with waterborne Se in British Columbia is the potential for its bioaccumulation in aquatic food chains.
Treatment to remove Se from coal-mining waste waters has proven to be challenging for conventional water-treatment technologies. Compounding this challenge, many streams are characterized by high flows and low selenium concentrations. Conventional membrane and ion exchange treatments produce concentrated brine streams that are difficult to treat or require disposal. Conventional biotreatment systems use excess nutrients to provide the required electrons to compensate for inefficient and variable electron availability, as well as to adjust reactor chemistry.