A Pilot-Scale Passive System for the Treatment of Acid Mine Drainage

Abstract

Acidic drainage water from mines, with different composition and containing sulphuric acid, sulphates, toxic heavy metals, (Cu, Zn, Cd, Mn, and Fe), arsenic and solid iron precipitates as well as radioactive elements (U, Ra and Th) as the main pollutants, were treated using a pilot-scale passive system. The system consisted of an anaerobic cell, filled with a mixture of spent mushroom compost, cattle manure and sawdust, was inhabited by a microbial community consisting of sulphate-reducing bacteria and other metabolically inter-dependent micro-organisms.

An efficient removal of the pollutants mentioned above was achieved in the cell under continuous flow conditions. Removal was linked mainly to processes such as those of microbial dissimilatory sulphate reduction and sorption on the organic matter. Effluents from the anaerobic cell were enriched in dissolved organic compounds that were degraded in the model wetland were foung to contain none of the pollutants in concentrations higher than the relevant permissible levels for waters intended for use in agriculture and/or industry.

The passive system described in this paper is found to be efficient, effective and relatively simple in its configuration. It has much to recomment itself for the treatment of mine wastewaters containing a wide range of pollutants.