无砾石微孔管地下渗滤系统对生活污水处理效果的研究

Study on the performance of gravel less perforated pipe leach fields on domestic sewage treatment

以壤土、河砂为填充基质,构建了5个无砾石微孔管地下渗滤系统,在3.3cm/d的水力负荷下,比较了5个系统对生活污水的处理效果。结果表明,无砾石微孔管地下渗滤系统对生活污水具有较好的处理效果,其中以上层填充河砂、下层填充壤土的系统C对生活污水的综合处理效果最好,其对COD、TP、浊度、NH3-N、TN的平均去除率分别为82.4%、74.1%、94.2%、98.4%、59.3%,相比传统的全部填充壤土的系统A分别提高了1.4、21.9、5.1、61.8、18.6百分点,且出水COD、TP、浊度、NH3-N、TN均达到了国家《城镇污水处理厂污染物排放标准》(GB 18918—2002)的一级标准。对系统NH3-N和TN的去除机制分析表明,碳氮比过低可能是导致TN去除效果不理想的主要原因。

Five kinds of gravelless perforated pipe leach fields （GPPLF） experimental devices were established with clay or river sand as padding substrate. The performance of these devices on rural sewage treatment under hydraulic loading of 3.3 cm/d was investigated. Results showed that GPPLF presented perfect sewage treatment performance. Device C, with up- per layer filled with river sand and lower layer filled with clay, had the best comprehensive sewage treatment efficiency. The COD, TP, turbidity, NH3-N, and TN removal efficiency of device C was 82.4%, 74.1 %, 94. 2 %, 98. 4 %, 59.3% respective- ly, which was 1.4,21.9,5.1,61.8,18.6 percent higher than device A （conventional perforated pipe leach fields）. The effluent COD, TP, turbidity, NHa-N, and TN of device C could meet the first degree of integrated wastewater discharge standard （GB 18918-2002）. The NH3-N and TN removal mechanism revealed that lower ratio of carbon to nitrogen was probably the key reason of unsatisfactory TN treatment efficiency.