Department of Municipal Engineering, Hefei University of Technology, Hefei China, 230009 E-mail:
Power Construction Corporation of China, Hangzhou, China, 310014.
Water Sci Technol. 2020 Dec;82(11):2472-2481. doi: 10.2166/wst.2020.516.
Previous studies on the extraneous water problem (or infiltration/inflow) in sanitary sewer systems assumed that the wastewater flow is mainly composed of foul sewage (FS), groundwater infiltration (GWI) and rainfall-derived inflow and infiltration (RDII). Most existing assessment methods are based on this assumption. In 2018, China initiated the 'Protection of the Yangtze River Program', and the two-year research data showed that it was neither the GWI nor the RDII but the direct surface water intrusion (DSWI), which has rarely been reported in literatures, that serves as the main source of the extraneous water in many local sewer systems. The discovery has enriched the understanding of the extraneous water in sewer systems. Meanwhile, it brings new challenges for the assessment of extraneous water. In this study, starting from the analysis of the low influent concentration of chemical oxygen demand (COD) of the wastewater treatment plant in a southeastern city in China, a river water intrusion point was successfully localized and the volume of river water intrusion was quantified by a series of field experiments. The methodology used in this study can also be applied in other areas with DSWI.
先前有关污水排水系统外来水分（或渗流/流入）问题的研究假设废水主要由污水（FS）、地下水渗流（GWI）和降雨衍生的流入和渗流（RDII）组成。大多数现有的评估方法都是基于这一假设。2018 年，中国启动了“长江保护计划”，为期两年的研究数据表明，造成外来水分的主要原因既不是 GWI 也不是 RDII，而是文献中鲜有报道的直接地表水入侵（DSWI），这一发现丰富了人们对排水系统外来水分的认识。同时，这也给外来水分的评估带来了新的挑战。在本研究中，从中国东南部某城市污水处理厂进水化学需氧量（COD）浓度低的分析入手，通过一系列现场试验成功定位了河水入侵点，并量化了河水入侵的水量。本研究中使用的方法也可以应用于其他有 DSWI 的地区。
