Evaluation of nitrogen removal efficiencies for predenitrification and alternating system

Predenitrification is commonly regarded as one of the most efficient activated sludge systems in terms of organic carbon utilization and nutrient removal balance. This paper outlines comparative evaluation of predenitrification with alternating activated sludge system for total nitrogen removal. Performance evaluation is made on the basis of model simulation using AQUASIM computer program and the general characterization of Istanbul sewage. The alternating system is observed to provide a higher nutrient removal efficiency at the same volume and sludge age through appropriate manipulation of control parameters.