Study On Domestication And Denitrification And Phosphorus Removal Of Denitrifying Phosphorus Accumulation

Denitrifying Phosphorus Removing Bacteria (DPB) is a microorganism that has function of "a carbon dual-use" and can improve wastewater carbon carbon utilization efficiency. Base on new denitrification and phosphorus removal technology, DPB shows good prospects on low-carbon wastewater treatment.The contents of this paper contained three parts. DPB acclimation and the optimum reaction time in the anaerobic phase and the anoxic phase; In different C/N flow conditions, researching COD removal efficiency and nitrogen and phosphorus removal capacity in denitrification and phosphorus removal system to find the C/N value that nitrogen and phosphorus removal can reach best; When excess nitrate in the anoxic phase, researching the effect of nitrogen and phosphorus removal capacity by adding external carbon source to find the carbon optimal dosage and time, and researching the effect of nitrogen and phosphorus removal capacity in short aeration phase after anoxic phase.Experimental results show:l.The experiment acclimated denitrifying phosphorus removal system by the way of simulated wastewater. COD concentration was controlled in 300mg/L and MLSS was controlled in 300mg/L. The first step was anaerobic-aerobic mode, After 13d, aerobic phase effluent TP removal rate reached 71.38%. PAOs in the system had a lot of enrichment. The second step was anaerobic-anoxic mode, After 25d, anoxic influent nitrate concentration was 50mg/L, anoxic phase effluent nitrate removal rate reached 98.35% and TP removal rate reached 61.13%. This shows that the acclimation of denitrifying phosphorus removal system has been basically completed. The reaction time in anaerobic phase and anoxic phase controlled in 120min and 150min was appropriate.2.Based on the DPB denitrification phosphorus removal in the anaerobic phase carbon conversion has significant limit (is saturated carbon source), when MLSS was controlled in 300mg/L, the saturated concentration of carbon source in the anaerobic phase was 250mg/L. Different conditions of influent COD concentration, NO3-N removal is proportional to the concentration of COD in the denitrification and phosphorus removal system. When excess NO3--N can not be completely removed, the system will incomplete denitrification and lead to the accumulation of NO2-N in the anoxic phase. When the influent C/N is stable at about 3.3, TP removal in system works best.3.Through adding external carbon source in the anoxic phase can remove nitrate, but it will inhibit TP removal. By delaying the time of adding external carbon source in the anoxic phase can slow down the Inhibition of TP removal. When the concentrations of COD was controlled in 250mg/L, the concentrations of NO3--N was controlled in 100mg/L, Adding in 100mg/L carbon source after 150min when anoxic reaction started can incresase the effluent TP removal rate from 19.08% to 44.25%. Adding a short aerobic phase after the anoxic phase can remove the remaining effluent TP, When the system still remaining TP after the anoxic phase, add a short aerobic phase and adding external carbon source in the short aerobic phase can improve effluent TP removal. When adding 100mg/L carbon source in the short aerobic phase, TP removal rate increased from 36.08% that never added carbon source to 59.17%.