The conditions of oxic-settling-anoxic process on sludge reduction in the active sludge system

This paper studied the effect of microbial species grow speed(MPGS), soluble microbial populations(SMPs) on the excess sludge production in the oxic-settling-anoxic process (OSA process), a modification of conventional activated sludge process by inserting a sludge holding tank in a sludge return line. The OSA process may provide a cost-effective way to reduce excess sludge production in activated sludge processes. The system was operated using synthetic wastewater for 4 months. The results showed that MPGS and SMP did not affect the sludge reduction. It was also found that the OSA system performed better than the traditional system in terms of the chemical oxygen demand removal efficiency and sludge settle ability.