An examination of the characteristics of an activated sludge operating under low-level salinity conditions

The effect of chlorides, bromides and iodides on the biochemical and physicochemical properties of activated sludge was examined. The properties studied were the oxygen uptake rate, the settlement and dewatering properties and the particle size distribution. The concentrations of halide ions used ranged from 500-10,000 mg l(-1). None of the ion types or concentrations altered the settlement of the sludge (measured as the sludge volume index) or the dewatering characteristics (measured as the capillary suction time). Iodide's, in particular, caused a change in the specific oxygen uptake rate. The halide ions also had an effect on the size distributions of the sludge.