Assessing the Performance of Constructed Wetland for Acid Mine Drainage Treatment Using Sugarcane Molasses as a Carbon Source

Abstract

Acid mine drainage (AMD) is a widespread environmental issue at mining sites globally. AMD is caused by pyrite oxidation which produces an acidic discharge > 2500 mg/L of sulfate, dissolved heavy metals at high amounts and low pH (2 - 4.5). AMD has serious health impact on living organisms. The present study aimed to assess the performance of locally available, high-organic matter containing by-products, specifically sugarcane molasses (SCM), as a carbon source for AMD treatment. In batch experiments containing SCM and control, 99% sulfate and nitrate reductions were reached. Heavy metal removal efficiencies > 94% were achieved for Cu, Fe, Mn, and Zn, in the SCM inoculated columns, while efficiencies > 42% were recorded in the control columns. The column experiments removed 99% of the initial Al concentrations but were not very effective in COD reduction to acceptable limits. The findings reported by this study verify that high carbon containing substrates can be used to remediate metal and sulfate contaminated water in mining areas.