地下渗滤处理村镇生活污水的中试

以红壤土作为填充土壤,在2cm/d的水力负荷下,进行了地下渗滤系统处理村镇生活污水的现场中试.结果表明,地下渗滤系统对COD、氨氮、总磷和总氮有着良好的去除效果,去除率分别达到84.7%、70.0%、98.0%和77.7%,出水COD、氨氮、总磷和总氮的平均浓度分别为11.7mg/L、4.0mg/L、0.04mg/L、4.7mg/L,达到建设部颁发的生活杂用水水质标准对总氮去除机理的分析表明,由硝化/反硝化实现生物脱氮是地下渗滤系统去除总氮的主要途径.在本中试系统中,反硝化效果良好但硝化效果不够理想,改善土壤环境以促进硝化作用是提高总氮去除率的关键.对土壤中氧化还原电位的测定结果表明,土壤内部的还原性质是阻碍硝化反应进行的主要原因.

Pilot Study on Subsurface Wastewater Infiltration System Applied in Rural Sewage Treatment

A pilot plant of subsurface wastewater infiltration system (SWIS) filled with red clay was tested to treat rural sewage with hydraulic loading of 2 cm/d. The experiment results showed that average removal rates of COD, NH₄⁺-N, total phosphorus, and total nitrogen were 84.7%, 70.0%, 98.0% and 77.7%, with average effluent concentrations of COD, NH₄⁺-N, total phosphorus, and total nitrogen being 11.7 mg/L, 4.0 mg/L, 0.04 mg/L and 4.7mg/L respectively, which met the standard for water reuse issued by the Ministry of Construction of China. Nitrogen removal mechanism analysis revealed that nitrogen in the influent was mainly eliminated through biological removal via nitrification/denitrification processes. In the pilot system, denitrification was well proceeded but nitrification was not satisfactory. How to improve nitrification performance through change of soil environment was the key to enhance nitrogen removal rate. The measurement results of redox potential in the filled soil showed that reductive property of soil was main hindrance to nitrification process.