Nitrification Processes in Tehran Wastewater Treatment Plant

Abstract

A wastewater treatment plant is designed to daily treat 450000 m 3 of wastewater collected from the city of Tehran. The wastewater treatment plant is located at the south of Shahr-Ray in southern Tehran with the area of 110 hectares. The treatment plant effluent will be transferred to Varamin agricultural lands to be used for the irrigation of crops. A conventional activated sludge for carbon removal and a high-rate trickling filter for nitrification of ammonia to nitrate are designed and constructed. The treatment plant consists of inlet pumping station, primary treatment, primary sedimentation tanks, selector and aeration tanks, trickling filter, and sludge treatment units. A mass balance analysis method which is a new approach for optimum design is used to achieve cost saving for the construction of south Tehran wastewater treatment plant. The comparison between combined system of activated sludge with trickling filter and an activated sludge alone shows that the combined system is 20% less costly and more efficient for the treatment of Tehran wastewater, the system has low volume demand, maximum biogas yeild, and low process control and is less variable to pH and chemical effects and highly energy-efficient.