Biowin3 model for carbon source and hydraulic retention time on removal performance of nitrogen and phosphorous

Static and dynamic simulation of effect of carbon source and hydraulic retention time (HRT) on removal performance of nitrogen and phosphorous were carried out by using activated sludge model software Biowin3 for typical anaerobic-anoxic-aerobic (A²/O) process in municipal wastewater treatment plant. The static simulation results showed that increasing C/N and C/P could improve obviously removal performance of nitrogen and phosphorous than extending hydraulic retention time (HRT). Under different HRTs, total nitrogen and phosphorus in effluent decrease linearly with increase of C/N and C/P. However, the relation between effect of HRT on nitrogen and phosphorus removal performance and carbon source was complicated. When C/N and C/P was low, extending HRT could improve removal performance of nitrogen; When C/N and C/P was high, removal performance of nitrogen and phosphorus would not change with HRT changing. The simulation results showed that dynamic simulation results were consistent with the static simulation ones, and also the system showed better removal performance for nitrogen and phosphorous by controlling suitable C/N and C/P.