Anaerobic treatment of sulphate-rich wastewaters

Until recently, biological treatment of sulphate-rich wastewater was rather unpopular because of the production of H2S under anaerobic conditions. Gas eous and dissolved sulphides cause physical-chemical (corrosion, odour, inc reased effluent chemical oxygen demand) or biological (toxicity) constraint s, which may lead to process failure. Anaerobic treatment of sulphate-rich wastewater can nevertheless be applied successfully provided a proper treat ment strategy is selected. The strategies currently available are discussed in relation to the aim of the treatment: i) removal of organic matter, ii) removal of sulphate or iii) removal of both. Also a whole spectrum of new biotechnological applications (removal of organic chemical oxygen demand, s ulphur, nitrogen and heavy metals), recently developed based on a better in sight in sulphur transformations, are discussed.