Study Of Treating Rural Domestic Sewage By ABR-composite Flow Constructed Rapid Infiltration Bed System

Rural sewage in China is dispersed,and widespread phenomenon such as shortage of funds,lack of technology and long-term effectiveness technology lays restrains on technology of water treatment.Based on this,the practical wastewater treatment technology including less investment,low running cost,low power consumption,stable operation and high water quality of the practical wastewater treatment technology,is the vital approach to solve existing environment problem of rural water in China.This research combined anaerobic baffled reactor?ABR?process and Composite Flow Constructed Rapid Infiltration Bed?CCRI?process to solve rural sewage.In allusion to ABR reactor,the reaserch focused on start up course in underload starting method,which immobilized water concentration and shortenes hydraulic retention time.The research embarked on the relationship between removal rate of COD_Cr and organic load,the change law of the pH and SS.The result showed that when COD_Cr concentrations of inflow water changed from 400 mg/L to 620 mg/L,effluent COD_Cr concentration could get up to 200 mg/L,while COD_Cr removal rate increased gradually to about 65%.Effluent pH values were always above 6.5 and no severe acidification phenomenon.SS concentration of inflow water changes from 150 mg/L to174 mg/L,with the matching,effluent concentration was lower than 20 mg/L,which proved that efficiency of pollutant removal is higher.In allusion to Composite Flow Constructed Rapid Infiltration Bed process,based on traditional rapid infiltration process,the system added water backflow device,nitrogen removal tank and phosphorus removal tank to strengthen denitrification and phosphorus removal,and planted plants in the pool following artificial wetland.Matrix selection,plant selection,backflow,hydraulic loading and w/d ratio research were in consideration.The results showed that anthracite was chosen for filler of coarse filter.Upper formation of rapid infiltration pool was filled with biological ceramsite and local fertile soil,and volcanic were chosen as below formation.Gravel with some corncob was selected as filler of denitrification tank and anthracite and bilological ceramsite were mixed by 1:1 as filler of phosphorus pool.Canna and Lythrum plant are selected as to high removal efficiency.When reflux ratio was 25%,contaminant removal was most efficient for system.COD_Cr,NH₄⁺-N,TN and TP removal rates were 65%,77%,52%and 60%respectively.When the hydraulic loading was 1.0m/d,contaminant removal was most efficient.Concentrations of COD_Cr,NH₄⁺-N,TN and TP are reduced to 15 mg/L,4 mg/L,8-9 mg/L and 0.9 mg/L respectively.When the ratio of w/d ratio was 8h:24h,system for contaminant removal was most efficient.Effluent concentrations of COD_Cr,NH₄⁺-N,TN,TP can reach 15 mg/L,4 mg/L,8-9 mg/L and0.9 mg/L.According to the experiment design,treatment effect was more ideal when combined ABR and Composite Flow Constructed Rapid Infiltration Bed process in one units.Effluent concentration of COD_Cr,SS,TN and TP could reach the"urban sewage treatment plant pollution emission standards"?GB18918-2002?.