Experimental study on treatment of rural domestic sewage with soil infiltration system

A soil infiltration system is applied for treatment of rural domestic sewage.The removal efficiencies of CODCr,BOD5,NH3-N,TN and TP in the process are investigated.The result shows that when the influent load is 0.05 m3/(m2·d) and hydraulic retention time is 3-day,the removal process may achieve better removal efficiencies of CODCr,BOD5,NH3-N,TN and TP.The average removal efficiencies of CODCr,BOD5,NH3-N,TN and TP in the process are 84.6%,83.3%,64.3%,59.8% and 70% respectively.In the effluent,CODCr is about 18.3～42.1 mg/L,BOD5 is about 8.9～17.3 mg/L,NH3-N is about 11.2～17.7 mg/L,TN is about 21.2～31.3 mg/L and TP is less than 2.0 mg/L.It is better than that of standards for irrigation water quality(GB 5084—2005).Temperature variation and pollutant content in influent have obvious effects on treatment efficiency.In general,when the temperature is higher than 22 ℃,the lower the pollutant content in influent,the better the treatment efficiency is.