Abstract

Sulphide in limeyard waste-water is generally estimated to be present at levels of the order of 2,000-3,000 mg/l. Oxidation by air in the presence of manganese sulphate as catalyst is a possible removal technique but there is a likelihood of increasing the level of Total Dissolved Solids (TDS) in the effluent. Rice bran based granular activated carbon may be used as a catalyst to oxidise sulphide (up to 90%) by air, irrespective of the initial concentration of sulphide. The efficiency of removal of sulphide increases to 99% when an activated carbon packed counter current reactor is used. During the oxidation of sulphide in limeyard waste-water, 92% of the total oxygen demand and 90% of the dissolved protein were removed.