城镇污水处理厂低浓度进水原因分析及提升措施

城镇污水处理厂进水浓度偏低是污水治理提质增效的难题之一。以无锡市某污水处理厂为例,基于水质分析和调研资料,采用水量平衡三角法分析了进水浓度偏低的原因分析,提出了整治措施。分析结果表明:该厂进水中地下水或河水渗入量和雨水混入量比例分别为28.9%和9.8%;晴天时进水浓度偏低的原因为污水管网渗漏和低浓度工业废水纳管,雨天时进水浓度偏低的主要原因是小区管网雨水混入,COD和BOD₅降幅分别可达到65.4%和52.9%。针对上述问题,提出了完善排水管理体制、工业企业排水实行三管分设整改、细化管网渗漏的检测排查和有效修复、加强管网验收和质量监管、尽量降低管网水位4项整治措施。

REASON ANALYSIS AND IMPROVEMENT MEASURES FOR LOW POLLUTANTS CONCENTRATION OF INFLUENT WATER OF URBAN SEWAGE TREATMENT PLANTS

The low pollutants concentration of influent water from urban wastewater treatment plants is one of the key problems to be solved for improving quality and efficiency of sewage treatment. Taking a sewage treatment plant in Wuxi City as an example, based on water quality analysis and research data, the cause of low concentration of influent water was analyzed by water balance triangle method and remedial measures were put forward. The results showed that 28.9% and 9.8% of groundwater or river water infiltration and rainwater infiltration were respectively in the inflow of sewage treatment plant. Leakage of sewage pipeline network and dilution of low concentration industrial wastewater were the main reasons for low concentration of water inflow in sunny days, while the main reasons for low concentration of water inflow in rainy days were mixed rainwater in pipeline network of residential quarter, then COD and BOD₅ decreased by 65.4% and 52.9% respectively. In view of the above problems, this paper put forward four improvement measures, such as improving the drainage management system and mechanism, implementing the three pipe separation rectification for industrial enterprise drainage, refining the detection, investigation and effective repair of pipe network leakage, strengthening the acceptance and quality supervision of the pipe network, and reducing the water level of the pipe network to enhance influent concentrations of the urban wastewater treatment plant.