Proposal and Testing of Multi-Step Process for Acid Mine Drainage Treatment

Abstract

The mining represents one the most common human activities that fundamentally impact not only the country itself but also have adverse effects on the fauna, flora and human beings. The negative impacts also include acid mine drainage which is formed by the dissolution of products resulting from the oxidation (chemically and microbiologically mediated) of sulphide minerals, mainly pyrite or iron disulphide. According to stringent European Union effluent discharge regulations it is necessary to look into innovative technologies to remove considerable amount of effluent rather than discharging into surface water. Resulting from previous partial achievements, the article is focused on the combination of chemical precipitation, ion exchange and biosorption techniques for the acid mine drainage treatment. Concentrations of four different metal cations (copper, iron, manganese, aluminium) and sulphates were observed. First stage of treatment included chemical precipitation by combination of oxidation using 31% hydrogen peroxide and subsequent precipitation with 0.1 M sodium hydroxide. After the first stage, the ion exchange using two different exchangers (PUROLITE MB400 resin and AMBERLITE MB20 resin) took place. The last stage of the experiments was focused of the biosorption study. Low – cost sorbents included in this case natural non – modified peat “PEAT - SORB” and hemp shives in modified state. Overall, the best results were observed after combination of MB20 resin in the second stage and subsequent using of modified hemp shives in the third stage of the treatment.