Shenandoah River Accumulated Wastewater Ratio

De facto wastewater reuse from Waste Water Treatment Facilities (WWTF) has the potential to be a significant contributor of Endocrine Disrupting Chemicals. An ArcGIS model of WWTFs, NHDPlus Version 2 stream networks (USGS and EPA 2012), and gage stations across the Shenandoah River watershed was created to calculate accumulated wastewater ratio. Virginia Pollutant Discharge Elimination System (VPDES) discharge facilities, VPDES outfall locations, and stream gages were spatially joined to the nearest river segment. Waste Water inputs from VPDES outfall locations were summarized by river segment COMIDs (Common identifier). All VPDES wastewater discharge facility locations were verified with VPDES outfall locations and United States Environmental Protection Agency (EPA) Facility Registry Service's facilities. WWTFs were categorized as industrial or municipal based on the type of permit they were granted. Accumulated wastewater and accumulated wastewater ratio were calculated using a python script. Maximum facility-capacity permitted wastewater discharge and 2015 average-annual wastewater discharge were used to calculate accumulated wastewater ratios for mean-annual and mean-August streamflow conditions.

污水处理厂（Waste Water Treatment Facilities, WWTF）产生的实际回用废水，有可能成为内分泌干扰物（Endocrine Disrupting Chemicals）的重要排放来源。本研究构建了一套ArcGIS模型，整合污水处理厂点位、2012年美国地质调查局（USGS）与美国环境保护署（EPA）发布的NHDPlus第二版河网，以及谢南多厄河流域内的所有河道水文测站，用于计算累积废水比率。将弗吉尼亚污染物排放消除系统（Virginia Pollutant Discharge Elimination System, VPDES）的排放设施、VPDES排放口位置与河道水文测站，空间连接至最近的河道河段。基于河段通用标识码（Common identifier, COMIDs），汇总各河道河段来自VPDES排放口的废水输入总量。所有VPDES废水排放设施的点位，均通过VPDES排放口数据与美国环境保护署设施登记服务的设施信息完成了交叉验证。根据所持许可类型，将污水处理厂划分为工业类与市政类两类。通过Python脚本计算得到累积废水总量与累积废水比率。分别以设施许可最大废水排放量，以及2015年年度平均废水排放量为基准，计算了年平均径流量与8月平均径流量条件下的累积废水比率。