School of Sustainable Engineering and the Built Environment, Arizona State University , Tempe, Arizona 85287-5306, United States.
Environ Sci Technol. 2013 Oct 1;47(19):11099-105. doi: 10.1021/es402792s. Epub 2013 Sep 18.
De facto wastewater reuse is the incidental presence of treated wastewater in a water supply source. In 1980 the EPA identified drinking water treatment plants (DWTPs) impacted by upstream wastewater treatment plant (WWTP) discharges and found the top 25 most impacted DWTPs contained between 2% and 16% wastewater discharges from upstream locations (i.e., de facto reuse) under average streamflow conditions. This study is the first to provide an update to the 1980 EPA analysis. An ArcGIS model of DWTPs and WWTPs across the U.S. was created to quantify de facto reuse for the top 25 cities in the 1980 EPA study. From 1980 to 2008, de facto reuse increased for 17 of the 25 DWTPs, as municipal flows upstream of the sites increased by 68%. Under low streamflow conditions, de facto reuse in DWTP supplies ranged from 7% to 100%, illustrating the importance of wastewater in sustainable water supplies. Case studies were performed on four cities to analyze the reasons for changes in de facto reuse over time. Three of the four sites have greater than 20% treated wastewater effluent within their drinking water source for streamflow less than the 25th percentile historic flow.
事实上的废水再利用是指经过处理的废水在供水源中偶然存在。1980 年，美国环保署（EPA）确定了受上游废水处理厂（WWTP）排放影响的饮用水处理厂（DWTP），并发现受影响最大的 25 个 DWTP 在平均流量条件下，来自上游地点（即事实上的再利用）的废水排放量在 2%至 16%之间。本研究首次对 1980 年 EPA 的分析进行了更新。创建了一个跨美国的 DWTP 和 WWTP 的 ArcGIS 模型，以量化 1980 年 EPA 研究中前 25 个城市的事实上的再利用情况。从 1980 年到 2008 年，25 个 DWTP 中有 17 个的事实上的再利用率增加，因为这些地点上游的市政流量增加了 68%。在低流量条件下，DWTP 供应中的事实上的再利用率在 7%至 100%之间，这说明了废水在可持续供水方面的重要性。对四个城市进行了案例研究，以分析事实上的再利用率随时间变化的原因。四个地点中有三个在其饮用水源中，其处理后的废水排放量超过其流量小于第 25 个百分位数历史流量的 20%。
