基于南方城市化粪池前后水质变化特征的若干思考

Research on the characteristics of water quality changes before and after septic tank in southern cities

在全国普遍污水处理厂进水浓度低、污水系统提质增效持续推进的背景下,对华南地区某市260个生活小区全面监测,以3个不同特征的典型居民小区为研究对象,对化粪池前后水质进行了全时段监测分析,探究化粪池设置对城市生活污水水质变化特征及其原因,为污水收集系统建设改造提供方向.分析结果表明,化粪池对各小区COD、BOD5、TSS平均削减率分别为8.4%~28.3%、5.7%~39.0%、21.7%~55.1%,TN、TP,削减率几乎均不足10%,化粪池未明显改善生活污水可生化性与C/N比,主要原因是在南方城市化粪池前进水污染物基底浓度不高的情况下,小区化粪池停留时间不足导致化粪池未能充分发挥作用,大分子颗粒态污染物水解转变为溶解态污染物后未能进一步消化分解,一定程度上减弱了化粪池削减效果.

In the context of low influent concentration of wastewater treatment plants in general nationwide and the continuous promotion of quality and efficiency of wastewater systems,in order to explore the characteristics of septic tank settings on the changes of urban domestic wastewater quality parameters and to deeply analyze the work direction of wastewater system construction and renovation,the water quality before and after scptic tanks was monitored and analyzed for the whole period of time in a residential district of a city in South China as the research object.The research results show that the average reduction rates of COD,BOD;and TSS of septic tanks for each community are 8.4%~28.3%,5.7%~39.0%and 21.7%~55.1%,respectively,and the reduction rates of TN and TP are almost all less than 10%.Septic tanks have not significantly improved the biochemical properties and C/N ratio of domestic wastewater.The main reason is that under the condition of low concentration of water pollutants at the base before the Septic tank in southern cities,the residence time of the Septic tank in the community is insufficient,which leads to the failure of the Septic tank to give full play to its role.After the particulate pollutants are converted into dissolved pollutants,which may lead to the failure of further digestion and decomposition of dissolved pollutants,carrying out limited reduction effect.