Study On The Performance And Kinetics Of Nitrogen And Phosphorus Removal In Humic Activated Sludge A~2/O System

Excess nitrogen and phosphorus discharged into natural water bodies isconsidered to be the most important reason for "eutrophication". From sustainabilityand cost-effective aspect of wastewater treatment, BNR technology is the bestoption. With increasingly stringent effluent standards of national urban sewage,many sewage treatment plants cannot meet the latest emissions requirements fornitrogen and phosphorus. The main problems that most of the sewage treatmentplants are facing in the actual operation are insufficient carbon, biological nitrogenand phosphorus removal efficiency instability and high sludge production.Therefore, research and development a BNR technology to solve these problems hasbecome particularly urgent. Humic activated sludge technique is a new biologicalwastewater treatment technology could improving activated sludge process nutrientand phosphorus removal efficiency and reduce sludge production, had substantialadvantages to solve the problems mentioned aboved.In this study, by coupling of humic activated sludge technique and A2/Oprocess developing a humic activated sludge A2/O system(HS-A2/O). This papersystematically studied the mechanism of humic activated sludge strengthening A2/Oprocess nitrogen and phosphorus removing efficiency. By dynamics analysis ofHS-A2/O system, explored the operating mechanism of HS-A2/O system.Investigated the effects of humic activated sludge reactor operating parameters onpollutant removal efficiency of A2/O process and optimized.Test results of HS-A2/O system treating domestic wastewater showed thathumic activated sludge can effectively enhance A2/O process10%TN removalefficiency, but COD and TP removal efficiency slightly improved. Compared sludgeproduction of HS-A2/O system and A2/O process, HS-A2/O system is lower about30%, residual sludge organic matter content of HS-A2/O system is18.5%lowerthan A2/O process, humic acid content is20.4%higher, resulting in a more stable.sludge. Compared biological phosphorus and nitrogen removal efficiency in lowC/N ratio domestic sewage treatment, HS-A2/O system TN and TP are higher about10%than A2/O process. When sludge retention time (SRT) extended to24d, HS-A2/O system showed a good performance on contaminant removal, COD, TNand TP removal efficiency maintained at about95.3%,87.0%and90.5%.Operation parameters of humic activated sludge reactor(HSR) have asignificant effect on contaminants removal efficiency of HS-A2/O system, testresults showed that: Absorption of humic acid by activated sludge conformed toFreundlich isotherm adsorption equation, adsorption process compliespseudo-second-order kinetic equation, adsorption kinetic constants has a goodlinear relationship with microbial biomass. Dissolved oxygen has little influence onactivated sludge adsorption of humic acid. Prolonged HSR-HRT, increasing HSR-R,elevated temperatures and reduced HSR-DO could improve HSR reducing humicacid capacity. HSR optimum HSR-R, HSR-DO, HSR-HRT and temperature are10%,0mg/L,24h and20℃. HS-A2/O system COD, TN, TP removal efficiency werestable at91%,83%,93%under optimum operational parameters.Test results of humic activated sludge promote biological nutrient removalshowed that:Humic activated sludge significantly enhance biological denitrificationrate, rapidly reduced ORP and improved pH value in the denitrification process. Byenhancing anaerobic hydrolysis generation amount of VFAs to promote PAOsinternal carbon source synthesis to realize humic activated sludge promotingbiological phosphorus removal.Kinetic analysis of HS-A2/O system showed thathumic activated sludge increased besides anoxic tank1denitrification constantsentire A2/O process kinetic constants...