Efficiency of Humus Filter for Treatment of Domestic Sewage

A laboratory scale biofilter filled with humus refuse was used to treat domestic sewage,and a demonstration project was conducted.In laboratory research,the average removal rates of COD,NH 4+-N,TP and TN are 85.7%,96.3%,63.5% and 25.6% respectively.The effluent return can improve the removal rate of TN,and it can be increased to 49.8% and 63.8% when the return ratio is 10% and 20% respectively.In the demonstration project of 100 m3 /d in Yangzhong City,Jiangsu Prov-ince,the average removal rates of COD,NH 4+-N,TP and TN are 55.0%,100%,84.5% and 19.2% respectively.Except high TN in the effluent due to insufficient carbon source in denitrification phase,the concentrations of COD and TP in the effluent are less than 40 mg/L and 0.5 mg/L respectively,and NH 4+-N can not be detected.The filling materials used are proved to be safe and non-interfering with the reuse according to the leaching toxicity experiment and concentrations of heavy metals in the effluent.The construction cost for the demonstration project is less than 3 000 RMB/m3,and the operating cost isless than 0.1 RMB/m3.