Study On The Operation Of Phosphorus Removal In SBR System

The organic contamination and eutrophication were the principal character of the water pollution,and with nutrients like nitrogen(N)and phosphorus(P)at levels which exceed growth-limiting concentrations for these photosynthetic organisms,the eutrophication has induced serious deterioration to the quality of water environment.Phosphorus removal from wastewater was one of an effective approach for prevention of eutrophication in closed water systems.With merit of briefness,hily activity,low energy consumption,the sequencing batch reactor was researched extensively in treating municipal sewage.So the research on the performance and influence factor of the phosphorus removal in SBR system would be benefit to the application and spread of this process.The sequencing batch reactor treated the mocking domestic wastewater in the experiment.When anaerobic time was 2h,aerobic time was 6h,temperature was 20℃～25℃,pH value was 7.5～8.0,aeration was 0.15m³/h,and SRT was 20d,the CODcr,NH₃-N,TN,TP removal efficiencies were 74.5%～96.15%,77.49%～95.97%,31.12%～72.39%,80.43%～96.9%,respectively.So this system had the good effectiveness.The anaerobic phosphorus releasing was studied on the anaerobic time,organic substance,concentration of organic matter and nitrate.The anaerobic releasing amount of phosphorus was increasing when anaerobic time was increasing.The subsequence of organic substance on the anaerobic releasing amount of phosphorus was,sodium acetate＞amylum＞peptone.The anaerobic releasing amount of phosphorus was increasing when the CODcr concentration was increasing,however this tendency would be short when the CODcr concentration reached the bigger amout.So the maximal anaerobic releasing amount of phosphorus was about 17mg/L.When there was the nitrate nitrogen in the wastewater,the phenomenon of phosphorus accumulation would occur in the anaerobic course,and the phosphorus accumulation amount was increasing when the concentration of nitrate nitrogen was increasing,but the anaerobic releasing amount of phosphorus was reverse.So it was unfavourable to anaerobic phosphorus releasing with nitrate nitrogen.The phosphorus removal on SBR system was studied on the aeration, temperature,pH value.The effiency of phosphorus removal was increasing when the aeration was increasing.But when the aeration was greater than 0.15m³/h,the efficiency of phosphorus removal was constant.The effect of the hige temperature was bigger than low temperature to the polyphosphate bacterium,and the optimal temperature scope was 20℃～25℃.When pH value was hige or low,the activity of polyphosphate bacterium would reduce,and the good pH value scope was 7.5～8.0.The phosphorus removal on SBR system was studied on the concentration of organic matter and SRT.When the initial CODcr concentration was less than 450mg/L,the effiency of phosphorus removal was increasing that CODcr concentration was increasing.When initial CODcr concentration was 450mg/L,the effiency of phosphorus removal was bigger and it is 93.75%.When the initial CODcr concentration was greater than 450mg/L,the effiency of phosphorus removal would reduce rapidly.It was big to SRT in biological phosphorus removal.The efficiency of the phosphorus removal would reduce with long or short SRT,and the good SRT scope was 15d～20d.It was studied on the denitrifying phosphorus removal.With changing varied operating scheme—anoxia time was increasing form Oh to 2h,and the system optimization,the rate of denitrifying phosphorus accumulation with nitrate was 1.4mg/(L·h).When the anaerobic time was 2h,the anoxia time was 3h,the concentration of nitrite was 25mg/L,the rate of denitrifying phosphorus accumulation was 5.9mg/(L·h).When the concentration of nitrite was low,The anaerobic phosphorus releasing would occure for exhausting of nitrite in advance.When the concentration of nitrite was high, The denitrifying phosphate-accumulating organisms would be repressed since the concentration of nitrite was high,and the anoxia phosphate-accumulating with nitrite can not proceed.