Improvement of anaerobic treatment of tannery beamhouse wastewater by an integrated sulphide elimination process

Sulphide, and especially the undissociated form, hydrogen sulphide, is inhi bitory to anaerobic wastewater treatment processes. Tannery beamhouse waste water contains high concentrations of organic material which make an anaero bic treatment favourable, but it also contains high concentrations of sulph ide which cause difficulties for anaerobic treatment. The success of an ana erobic treatment will depend on reliable elimination bf the sulphide. In ba tch tests stripping was the most effective process for sulphide removal com pared to precipitation. The chemical-physical COD removal caused by the str ipping was negligible, while precipitation caused a GOD-removal of 26%. Als o, anaerobic degradation velocity was higher if sulphide was removed by str ipping. In fixed bed reactors operated continuously, stripping was shown to be a reliable method for eliminating hydrogen sulphide toxicity. Hydrogen sulphide caused an inhibition of 0.2% per mg l(-1) for methanogenic bacteri a. Acidogenic bacteria were not inhibited by hydrogen sulphide. The gas-liq uid equilibrium was shown to deviate from theoretical values taken: from li terature. (C) 1999 IAWQ Published by Elsevier Science Ltd. All rights reser ved.