Evaluation of nitrogen removal efficiencies for predenitrification and alternating system

Predenitrification is commonly regarded as one of the most efficient activa ted sludge systems in terms of organic carbon utilization and nutrient remo val balance. This paper outlines comparative evaluation of predenitrificati on with alternating activated sludge system for total nitrogen removal. Per formance evaluation is made on the basis of model simulation using AQUASIM computer program and the general characterization of Istanbul sewage. The a lternating system is observed to provide a higher nutrient removal efficien cy at the same volume and sludge age through appropriate manipulation of co ntrol parameters.