The Research On Biological Nutrients Removal In Sequencing Batch Reactor (SOA-SBR) Operated As Static/Aerobic/Anoxic Regime

Nowadays, eutrophication caused by excess discharge of nutrients (nitrogen (N) andphosphorus (P)) has been increasingly serious and become one of the important problemspaid attention to throughout the world. Scholars at home and abroad have developed ormodified various biological nutrient removal (BNR) processes to achieve excellent removalefficiencies, many of which, however, have complex treatment procedure and thus highexpense for construction and operation. In this work a novel BNR regime operated asstatic/aerobic/anoxic sequencing batch reactor (SOA-SBR) was proposed to investigate theBNR performance. Anaerobic phase was replaced by static phase without stirring besidespost-anoxic format in this BNR system with simple operation and low cost. The BNRperformance of static/aerobic/anoxic SBR (R1) was compared to that ofanaerobic/aerobic/anoxic SBR (R2) and then the effect of influent ammonia concentration onBNR efficiencies of static/aerobic/anoxic SBR was explored.The experimental results between R1and R2demonstrated that the P removal efficiencyin R1(92.4%) was comparative to R2(92.1%). However, total nitrogen (TN) removalefficiency of R1(83.5%) was higher than that of R2(77.0%). Static phase in R1still workedas anaerobic phase without stirring, which contributed to rapid P uptake in aerobic phase. Theeffluent P of0.91mg/L was achieved through denitrifying P removal in anoxic phase.Simultaneous nitrification and denitrification (SND) happening in aerobic phase realized18.0%of TN elimination in R1, much higher than that of R2(9.8%). In the post-anoxic phase,microorganisms utilized glycogen as carbon source to drive denitrification, exhibitingdenitrification rates (DNRs) of0.98,0.84mg-N/(g-VSS·h) and6.62,9.21mg/L of effluentTN in R1and R2, respectively. Better nitrogen removal efficiency was obtained withanaerobic phase replaced by static phase, and the configuration was further simplified.Four SBRs (R1, R2, R3and R4) were operated with influent ammonia concentration of20,30,40and50mg/L respectively. The results demonstrated that82.3%,92.8%,92.6%and89.1%of phosphorus (P) removal efficiencies and97.2%,88.6%,84.5%and72.6%of totalnitrogen (TN) elimination efficiencies were respectively obtained in R1, R2, R3and R4during the long-term operation. It could be concluded that static phase without stirring couldfunction as anaerobic phase in this process, and thus enhanced the biological phosphorusremoval. Simultaneous nitrification-denitrification (SND) was observed in the four systemsand achieved respective14.7%,16.6%,17.8%and14.8%of TN elimination. Post-denitrification was driven by glycogen, achieving0.57,4.43,6.61and13.70mg/L ofeffluent TN in R1, R2, R3and R4respectively. The research indicated that different influentammonia loadings had impacts on P release in static phase, aerobic P uptake and denitrifyingP uptake in anoxic period, but the BNR efficiencies of the four reactors were satisfied.