Biological remediation of acid mine drainage: Review of past trends and current outlook

Abstract

Formation of acid mine drainage (AMD) is a widespread environmental issue that has not subsided throughout decades of continuing research. Highly acidic and highly concentrated metallic streams are characteristics of such streams. Humans, plants and surrounding ecosystems that are in proximity to AMD producing sites face immediate threats. Remediation options include active and passive biological treatments which are markedly different in many aspects. Sulfate reducing bacteria (SRB) remove sulfate and heavy metals to generate non-toxic streams. Passive systems are inexpensive to operate but entail fundamental drawbacks such as large land requirements and prolonged treatment period. Active bioreactors offer greater operational predictability and quicker treatment time but require higher investment costs and wide scale usage is limited by lack of expertise. Recent advancements include the use of renewable raw materials for AMD clean up purposes, which will likely achieve much greener mitigation solutions.

Graphical abstract

Highlights

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  Various bio-remediation techniques available for AMD treatment are reviewed.

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  SRB based acidic effluent treatment with necessary information on their metabolism and process parameters are described.

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  Current trends in active and passive biological treatment methods with recent innovations in the field are presented.

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  Future outlook and potential research gaps in bio-remediation of AMD treatment are discussed.