Strengthening Of Denitrification And Phosphorus Removal Rate In SBR Process With Microaerobic Hydrolysis Acidification Products Of Sludge As Carbon

The deficiency of carbon source existed in the process of nitrogen and phosphorus removal from municipal wastewater universally,which seriously restricted the efficiency of nitrogen and phosphorus removal.Sludge treatment and disposal has also been a hot topic nowadays.The sludge micro aerobic hydrolysis and acidification products could offer external carbon source for the city sewage treatment process in SBR,supplying an effective way to solve the factory sewage non-compliance and sludge treatment problems.Human beings could realize the minimization and resource utilization of sludge,and reduce the cost of sewage and sludge treatment at the same time.As a result,sewage plant would achieve the aim of energy-saving and emission reduction in this way.In this paper,sludge micro-aerobic hydrolysis acidification products was used as carbon source for the treatment of low C/N ratio municipal wastewater in AOA-SBR technology system,researching the influence of the dosage of sludge micro-aerobic hydrolysis acidification products,sludge age(SRT)and aeration rate on the nitrogen and phosphorus removal.The COD aerobicdegradation dynamics in aerobic period,material balance and microbial community structure were studied in the SBR system.The conclusions are drawn as follows:(1)The treatment effect of p H and molar ratio of Mg/P in the removal of nitrogen and phosphorus from sludge micro-aerobic hydrolysis acidification products achieved optimal condition when the process was pH 10.0,ratio of Mg/P 1.8.The removal rate of phosphate,ammonia nitrogen and COD in SBR system was 93.08%,32.91% and 14% respectively.(2)Under the conditions of 25?,aeration rate of 48L/h and SRT25 d,the effect of different dosage of supernatant on the removal efficiency of nitrogen and phosphorus in AOA-SBR system was studied.The results showed that the removal rate of COD,total nitrogen and total phosphorus was 90%,68% and64% separately when the dosage of the supernatant was equivalent to COD 220mg/L.Because of the existence of ammonia nitrogen and phosphorus in the supernatant,the removal rate was not high.(3)Under the conditions of 25?,aeration rate of 48L/h and SRT25 d,the effect of different dosage of supernatant after the removal of phosphorus and nitrogen on the removal efficiency of nitrogen and phosphorus in AOA-SBR system was studied.The results showed that the removal rate of COD,ammonia nitrogen,total nitrogen and total phosphorus was 93%,99%,85% and 96%when the dosage of the supernatant was equivalent to COD 220 mg/L.The effluent quality reached first and A standard of pollutant discharge standard ofcity sewage treatment plant(GB18918-2002).Denitrifying phosphorus removal occurred in SBR system,and the proportion of denitrifying phosphorus removing bacteria was 15.98% and 18.41%,while the dosage of the supernatant was equivalent to COD 180mg/L and 220 mg/L respectively.(4)Under the conditions of 25?,SRT25 d and the dosage of supernatant after the removal of phosphorus and nitrogen was equivalent to COD 220mg/L,the effect of aeration rate on the removal efficiency of nitrogen and phosphorus in AOA-SBR system was studied.The optimal aeration rate was 48L/h.(5)Under the conditions of 25?,aeration rate of 48L/h and the dosage of supernatant after the removal of phosphorus and nitrogen was equivalent to COD 220mg/L,the effect of SRT on the removal efficiency of nitrogen and phosphorus in AOA-SBR system was studied.The suitable SRT was 20d~25d.(6)Under the conditions of 25?,aeration rate of 48L/h and SRT25 d the effect of different dosage of supernatant after the removal of phosphorus and nitrogen on the COD aerobic degradation dynamics in AOA-SBR system was studied.Obtained the degradation of COD in aerobic phase obeys the first-order kinetics,and the degradation rate constant of COD accelerated with the increase of the dosage of liquid supernatant.(7)Under the conditions of 25?,aeration rate of 48L/h,SRT25 d and the dosage of supernatant after the removal of phosphorus and nitrogen was equivalent to COD 220mg/L,the material balance in the A/O/A-SBR system was analyzed.The results showed that the equilibrium percentage of COD,nitrogen and phosphorus was 80.47%,94.71% and 94.4%.(8)In SBR system with A/O/A mode,large amounts of Ottowia,Comamonas and Thauera which were asserted denitrification bacteria were founded.The leading bacteria of nitrification was Nitrospira.The main phosphorus accumulating bacteria and typical denitrifying phosphorus removing bacteria were Acinetobacter and Dechloromonas respectively.