Research On Effect Of Constructed Rapid Infiltration Systems For Distributed Rural Sewage Treatment

At present, the majority of rural water is heavily polluted that is causing multiple water crisis of affecting the future China’s security and development.Disorderly discharging of rural sewage is an important cause of water pollution in rural areas,Improving rural water environment must be tackle rural sewage.In this paper, considering the rural economic level, the characteristics of sewage,catchment facilities and other factors,there is a research on Constructed Rapid Infiltration Systems for rural sewage treatment.In this paper,it has an improve measure that replaces river sand at50-90cm of the contrast system which is Constructed Rapid Infiltration System conventional with amount of sawdust mixed with soil.The result of comparative studying on the two systems shows that the new system’s average removal efficiency of COD,TP,NH4-N,TN increases from65.98%to79.50%,71.61%to85.54%,59.42%to80.67%,24.33%to72.69%.The superior of improve measure is verified preliminarily.Soon after, the new system continues to do the further experimental studying about hydraulic loading what is only changed from0.6m/d to0.8m/d.The result shows that the new system’s average removal efficiency of COD,TP,NH4+-N,TN is77.19%,78.01%,78.57%,66.65%,respectively and the concentration of COD,TP,NH4-N,TN is37.61mg/L,0.90mg/L,5.48mg/L,11.05mg/L,respectively.The quality of effluent water can achieve to the senior B standard of 《discharge standard of pollutions for municipal wastewater treatment plant》(GB18918-2002).The superior of improve measure is verified again.The reason is briefly summarized that improvement measures optimize the characteristics of the system and increase the reaction time what make the reaction more fully between sewage and system in favor of removing pollutant indexes;the region filled with water creates a part anaerobic micro-environment conducive to denitrification occurring in the system’s lower part;adding composted sawdust can provide more carbon for system’s lower part which conducive to removal of TN.