Study On The Enhanced Simultaneous Phosphorus And Nitrogen Removal Strategies Of The A~2/O Process Based On ASM2D

In view of the issues such as unstable operation existed in Chinese WWTPs, combined with the excessive effluent amounts of nitrogen and phosphorus and shock load of the A~2/O process in Shenzhen Binhe sewage treatment plant. The numerical simulation optimization was carried out to provide recommendations for process optimization and control of Shenzhen Binhe sewage treatment plant.Based on the GPS-X biochemical simulation software, the biochemical model of A~2/O was builded. static simulation and dynamic simulation. Based on the verified model, univariate simulation、multivariable simulation、varieties of A~2/O process effect、shock load simulation was carried out to obtain the optimal control measures for strengthen denitrification and phosphorus removal of A~2/O process. In univariate simulation, the internal return ratio, sludge recycle ratio, aerobic DO, SRT was investigated to impact of the effluent concentration to respectively investigate the impact of these factors on the water pollutant concentration. Based on the univariate simulation, multivariable simulation showed that the best control measures: MLR350% 、 RAS60% 、 DO1.3mg/L 、 SRT16 d 。 The effect on the effluent TN concentration : MLR> SRT >RAS> DO,The results showed that the effect on the effluent TP concentration: MLR> SRT> DO >RAS. The COD concentration is stable up to standard, The average concentration of effluent TN, NH4+-N, and TP were 14.2mg/L, 1.3mg/L, 2.45mg/L, respectively. The average removal rates of effluent TN,NH4+-N, and TP were 70%, 96.5% and 45%, respectively. Effluent TN and NH4+-N of conventional A~2 O process was better than section water A~2 /O process, when the influent flow of anaerobic and anoxic is equal, Effluent TP of conventional A~2 O process is worse than section water A~2/O process. The bese control mose for the convert A~2/O process is RAS180%~210%,DO2mg/L. when only adjust the volume of anaerobic and oxic, the anaerobic HRT is positively related with TP removal and negative related with TN and NH4+-N removal.In order to obtain optimal control strategy, the situation of the shock load was also examined in the plant. This results the efflue nt of pollutions were not met the discharge standard during the operation. The TN concentration mainly exceeded the discharge standard, by analysis the water data of 2015. This article divided shock load into two classes: continuous shock load; discrete sh ock load. The results showed that compared with air control, DO control will reduce the air flow, then reduce the operation cost in WWTPs in continuous shock load. Control measures for this is DO 4mg/L、 MLR 350%、 adding external carbon source; the control me ssure for discrete shock load is ―adjust the air、adjust MLR、 add external source‖.