Experimental Study On The Treatment Of Rural Domestic Wastewater With An Improved C-CBR Integrated Bioreactorr

The governance of rural water environment in China lags behind.The characteristics of domestic sewage in different rural areas vary greatly,and the level of economic development between urban and rural areas is uneven,resulting in backward design,construction,and operation of rural sewage treatment facilities.C-CBR integrated bioreactor,also known as continuous flow continuous biochemical reactor,is a new and practical activated sludge treatment process developed for rural domestic sewage treatment that can be promoted.By utilizing a combination of water pumps and jet pumps,continuous water inlet and outlet as well as continuous biochemical reactions are achieved,achieving a three-in-one function of nitrification liquid reflux,jet aeration,and hydraulic stirring.There were problems in the initial experiment:insufficient dissolved oxygen mass concentration and uneven distribution;There is a hydraulic dead corner in the reaction zone,and the sludge accumulates and turns black;The operation is complex and inflexible.Make improvements to the existing problems in the reactor.Add a set of"water pump+jet reactor"to add an aerobic aerobic cycle to the reactor,providing more dissolved oxygen to the aerobic zone;Another combination of anaerobic and aerobic"water pumps+jets"is used to control the reflux of nitrification liquid and supply oxygen to the aerobic zone;By improving the pipeline,the sewage in the outer and inner reaction zones can circulate and flow,playing a stirring role.Finally,an improved C-CBR integrated bioreactor was proposed to improve the removal rate of pollutants.Using the effluent from the sedimentation tank of the second sewage plant in Lankao County as the raw water,the quality of the effluent is determined according to the methods specified in national standards.By adjusting the flow rate of two sets of water pumps to change the operating conditions of the reactor,the removal efficiency of COD,ammonia nitrogen,TP,and TN in wastewater by the improved C-CBR integrated bioreactor was studied under different aeration rates,nitrification reflux ratios,and hydraulic loads,and the optimal operating conditions of the reactor were obtained.Adjust the internal circulation flow rate to change the dissolved oxygen concentration in the aerobic zone.Maintain internal circulation flow rates of 0.10 m~3/h,0.25 m~3/h,and 0.40m~3/h.At a reflux ratio of 400%for the nitration solution,when the internal circulation flow rate is 0.25 m~3/h,all four pollution indicators achieve the best removal effect.The removal rates of COD,ammonia nitrogen,TN,and TP were 85.0%,71.6%,64.0%,and 73.7%,respectively;Except for TP,which can only meet the second level standard of the"Water Pollutant Discharge Standard for Rural Domestic Sewage Treatment Facilities"in Henan Province,all others can meet the first level standard.Maintain an internal circulation flow rate of 0.25 m~3/h,adjust the reflux ratio of the mixture to 300%and 500%,respectively.Except for TP,which achieved the best removal rate at a reflux ratio of 300%,the removal rates of the other three pollution indicators all decreased.After the dissolved oxygen concentration in the aerobic zone increases to 3.0 mg/L,the COD removal rate decreases,and the majority of COD removal relies on the uptake of heterotrophic bacteria in the hypoxic/anaerobic zone.The optimal operating conditions for the reactor were determined to be an"internal circulation"flow rate of 0.25 m~3/h and a reflux ratio of 400%for the nitration liquid.During high load operation,the removal rates of COD,ammonia nitrogen,TN,and TP were 76.1%,67.3%,58.0%,and 60.2%,respectively,and the removal rates of each reaction zone decreased.TN effluent can still meet the provincial first level standards,COD and ammonia nitrogen can meet the second level standards,while the TP mass concentration in the effluent exceeds the second level standards.