Constructed Wetlands for Industrial Wastewater Treatment

12A Review on the Use of Constructed Wetlands for the Treatment of Acid Mine Drainage

C. Sheridan¹, A. Akcil², U. Kappelmeyer³ and I. Moodley¹

¹Industrial Mine Water Research Unit (IMWaRU), Centre in Water Research Development (CIWaRD), School of Chemical and Metallurgical Engineering (CHMT), University of the Witwatersrand, Johannesburg, South Africa

²Mineral-Metal Recovery and Recycling (MMR&R) Research Group, Mineral Processing Division, Department of Mining Engineering, Suleyman Demiral University, Isparta, Turkey

³Helmholtz Centre for Environmental Research-UFZ, Department of Environmental Biotechnology, Leipzig, Germany

12.1 What is Acid Mine Drainage?

Acid mine drainage (AMD) or acid rock drainage (ARD) is an environmental pollutant that is associated with mining activities. The production of AMD is actually a natural occurrence but mining activities have, however, accelerated this process, resulting in negative impacts to the environment [1–3].

In a natural environment small amounts of acid are produced when sulfide ore is exposed to an oxidizing environment and this occurs through the natural weathering of rocks that enclose sulfide. Subsequently, naturally occurring processes neutralize the acid, with surrounding alkaline rocks providing the most alkalinity [1]. These neutralization processes (shown below) include dissolution of carbonate substrates like calcite and dolomite [equations (12.1), (12.2)]; reduction of iron hydroxides within sediment [equation (12.3)]; and dissimilatory ...