Research On The Treatment Of Low Concentration Domestic Wastewater By SBR System And The Design Of The Project Of "Upgrading And Reconstruction"

The treatment of low concentration domestic wastewater is one of the difficult problems in wastewater treatment; its organic load is low. The wastewater treatment plants are operated in this environment for a long time, which will affect the activity of activated sludge and reduce the efficiency of nitrogen and phosphorus removal. In this paper, the SBR system is used to deal with the concentration wastewater of ShaoBo. According to the research results, the suitable depth treatment technology is selected, and the design of "upgrading and reconstruction" is finished.(1) By the orthogonal experimental method, research SBR equipment to the optimum working time for the treatment of low concentration domestic wastewater of ShaoBo:stirring time of input water is 30 min, aeration time is 2 h, stop aeration and stirring for 60 min, sedimentation time is 60 min, decanting and idle time is 2h. Running in the best condition, the concentration of COD and NH3-N can reach A in first grade discharge standard of "Discharge standard of pollutants for municipal wastewater treatment plant"(GB18918-2002),the concentration of TP can only reach B in first grade discharge standard of "Discharge standard of pollutants for municipal wastewater treatment plant"(GB18918-2002).(2)Through the research of sludge concentration:The removal rate of NH3-N, TP and COD were proportional to the sludge concentration, and the removal rate of NH3-N was high when the sludge concentration ranged from 1500 to 2500 mg/L, the removal rate of NH3-N was decreased slightly when the concentration of sludge was 2500 mg/L. Base on the removal rate of CODcr, NH3-N, TP, the 2500 mg/L concentration sludge was used in this study.(3) The effect of COD concentration in influent to Nitrogen and phosphorus removal in SBR system was studied. The removal rate of COD, TN, NH3-N and TP increased with the increase of COD concentration. When the COD concentration was increased in the influent, the removal rate of NH3-N increased from 85% to 88%, so we can make a conclusion that the organic load of the influent are not the main factors by the removal of NH3-N; TN and TP removal rate were 50%, so we can get that the bacteria are competing for organic nutrition in SBR system.(4)When the research that external carbon source enhance biological phosphorus removal under normal temperature conditions, we can get that biological treatment is nice in SBR system; when the dosage of glucose is 60 mg/L, we can get that the effluent index can achieve A in first grade discharge standard of "Discharge standard of pollutants for municipal wastewater treatment plant"(GB18918-2002). When the experimental study on the low temperature in winter (the laboratory temperature lower than 5 ℃), we can get that COD concentration in effluent increased with the increase of glucose; When the dosage of glucose more than 110 mg/L, we can get that COD concentration in effluent beyond A in first grade discharge standard of "Discharge standard of pollutants for municipal wastewater treatment plant"(GB18918-2002), and TP concentration in effluent is still not standard at this moment in time.(5) To improve phosphorus removal efficiency of the SBR system:PAC are added in the initial aeration stage of SBR system, we can get that the increase of PAC has certain inhibition effect of nitrogen removal in SBR system; when the dosage of PAC reach 80 mg/L, we can get that the effluent index can reach A in first grade discharge standard of "Discharge standard of pollutants for municipal wastewater treatment plant"(GB 18918-2002). PAC are added in the effluent of biological treatment, when the dosage of PAC is only 18 mg/L, we can get that TP concentration in effluent was less than 0.5 mg/L.(6) "Densadeg" is employ as chemical phosphorus removal process, "Densadeg" covers a smaller area and has better effluent; In Jiangsu Province, most of the wastewater treatment plants set filtration facilities in "upgrading and reconstruction", choose the height of the equipment of filtering technology-"Vertical cloth media filter"; So the technology of Shaobo’s wastewater plant "upgrading and reconstruction" is "Densadeg and vertical cloth media filter".