Modelling performance of oxidation ditch in wastewater treatment plant by STOAT software

Abstract

This paper adopted the IAWQ# 1 model based on ASM in STOAT software to model the treating performance of oxidation ditch. STOAT software is a free modeling package for numerical modeling and simulation of wastewater treatment plants (WWTP). The dynamic model evaluates the effects of influent water qualities (TN, TP and COD) and water flow rate on the pollutant removal efficiency. The model was able to predict the changing trend in terms of TN, TP and COD concentrations. The effluent TN and TP concentrations did not greatly affected by the change of influent TN and TP concentrations. The removal efficiency of TN was clearly stronger than that of TP. However, the COD removal performance of oxidation ditch was outstanding. Meanwhile, the water flow rate was of importance for the COD biodegradation efficiency. The increase of water flow rate was likely to decrease COD removal efficiency. The flow rate varied between 1000 and 10000 m3/h, and the effluent COD concentration varied from 118.98 to 501.49 mg/L. Overall, STOAT software is a useful and reliable tool for the prediction and optimization of oxidation ditch process.