山西省沁河流域农村生活污水入河水质研究

Research on the rural sewage quality for discharge to river in the Qin River valley of Shanxi

针对农村生活污水管理的需求,在水生态功能区和水环境控制单元的基础上提出了农村生活污水入河水质核算方法.具体步骤包括:①根据地貌类型、降水蒸发量、植被和土壤类型等指标,进行水生态功能区划分;②在水生态功能分区基础上,结合水文单元和行政区边界,划定水环境控制单元;③对控制单元内的水环境容量进行计算,并调查核算各类污染源污染物排放入河量,然后基于水环境容量和污染物入河量确定农村生活污水污染物排放限值.结果表明,沁河流域可划分为2个一级水生态功能区和7个二级水生态功能区,并划分为15个水环境控制单元.以控制单元内沁河上游水质改善区为例,区域内农村生活污水COD排放限值为134.05mg·L^-1,且此标准下河流不满足接纳农村污水进行NH3-N消减的条件.在以上研究成果基础上,提出了农村生活污水分区分级管理措施建议.

According to the demand of rural sewage management,a calculating method for water quality discharge to river was established in this study based on aquatic ecological function region and water environment control unit.The water quality was determined by follow steps.①According to geomorphological types,precipitation,evaporation,vegetation and soil types,the aquatic ecological function region was divided.②Boundary of water environment control unit was identified based on aquatic ecological function region,hydrological unit and administrative area.③The water environment capacity in the control unit was calculated.After that,the pollutants amount of discharge to river from various sources were investigated respectively.Then the discharge standard of pollutants for rural sewage were calculated.The aquatic ecological functional regions were divided into 2 first?grade regions and 7 second?grade regions,and 15 water environment control units were divided in Qin River valley.Taking the water quality improvement area in the upper reaches of the Qinhe River as an example,the COD emission limit of rural sewage was 134.05 mg·L^-1,and the river could not meet the requirement of NH3?N reduction for rural sewage under this standard.Moreover,regionalized management measures for rural sewage were proposed based on the above results.