农村生活污水分散式处理现状与问题探讨

农村生活污水治理是改善农村人居环境、实施乡村振兴战略的重要举措和全面建成小康社会的内在要求。基于农村生活污水分散式处理工艺的现状与问题的分析,对广东省农村生活污水处理工艺模式进行了实地调研,选取广州市增城区某村的厌氧+人工湿地工艺、珠海市斗门区某村的土地渗滤工艺、中山市横栏镇某村的MBR工艺和佛山市顺德区某村的A~2O工艺,进行定点检测,分析4种工艺对生活污水COD、NH_4~+-N、TN和TP的处理情况,探讨4种工艺的运行效果及其成因。结果表明,4种工艺总体上污染指标进水浓度波动较大,存在明显的峰值特征,去除率日变化系数较大,大部分污染指标的日均去除率低于60%。4种工艺的COD处理效果基本达标,但是氮磷超标较多,A~2O工艺和厌氧+人工湿地工艺的出水NH_4~+-N、TN和TP浓度未达到国家一级B标准,MBR工艺出水TP浓度未达到国家一级B标准,其原因与C/N过低、处理设施运行维护不善等有关。研究表明,对农村生活污水处理工艺的选择应遵循因地制宜的原则;使用中应加强处理设施维护管理,提高生活污水氮磷处理效率和长期持效性。

Present situation and problems of decentralized treatment of rural domestic sewage

Rural domestic sewage treatment not only severs as critical implication of the living surrounding improvement and the implementation of rural revitalization strategy, but also plays significant role in the comprehensive construction of a well-off society in an all-round way. The study carry out field surveys in Zengcheng district, Guangzhou city with anaerobic+AW technology, Doumen district, Zhuhai city with soil infiltration technology, Henglan district, Zhongshan city with membrane bio-reactor (MBR) technology, and in Shunde district, Foshan city with A2O technology. This paper analyze the discharge efficiencies of the four different technologies mentioned above on COD, NH4+-N, TN and TP, and to investigate the related environmental factors causing the differences. The results show a strong variation of the pollutant concentration with significant peaks in the day and the high varied daily removal coefficients, the average daily discharge efficiencies of most of the pollutants are less than 60% with respective differences among the four technologies. The treated sewage can basically meet the criterion of COD, but still contain excessive nitrogen and phosphorus. The NH4+-N, TN and TP concentrations in the effluence of the A2O and the anaerobic+AW technologies fail to meet the level B of the urban sewage discharge standards, so does the TP concentration for the MBR technology. The main reason is related to the low C/N and poor facilities maintenance, etc. The research suggest the site-specific principle in the suitable technology selection for the rural domestic sewage treatment, and the highlight of the facilities maintenance, to improve the removal efficiency of nitrogen and phosphorus and to acquire long-term effectiveness.