基于三角分析法的城市污水管网入流入渗量评估

Quantification of Inflow and Infiltration in Urban Sewer Systems Based on Triangle Method

摘要: 平原河网地区分流制污水系统普遍存在外来水入流入渗现象，管网输送能力和污水厂处理效能均受到负面影响。本研究采用三角分析法解析特定时间段内的污水管网出口流量，根据逐日水量平衡和降雨数据评估外来水量的规模与构成。对2014~2017年期间苏州市中心城区污水管网系统开展评估，结果表明，每年外来水总量占管网收集总水量的27%~33%；旱天和雨天的外来水量日均占比分别为22%和43%，其中雨天管网平均入渗率16%、平均入流率27%，降雨对入流入渗的驱动作用明显。本研究识别了案例区污水管网入流入渗特征，验证了入流入渗给系统运行带来的压力，解析结果可为制定管网修复方案提供依据。

Abstract: Inflow and infiltration of external water into sewer systems exist generally in the plain river net-work area, which weakens the transmission capacity of pipelines and the efficiency of the wastewater treatment plants. In this study, triangle method is applied to analyze the outlet flow of sewage pipelines in a specific time period. The scale and composition of the external water volume are evaluated according to the principle of water balance using daily wastewater treatment plant inflow data and rainfall data. The assessment of the sewer system in Suzhou central district during the period of 2014-2017 shows that the amount of external water accounts for 27% - 33% of the total flow collected annually. Average daily external flow accounts for 22% in dry days and 43% in rainy days, among which the average infiltration and inflow rates are separately 16% and 27%. The severity of inflow and infiltration in wet weather is derived and intensified by the rain. This study identified the inflow and infiltration characteristics of the sewer systems in the case area, and verified the adverse effects of external water on the operation of the systems. The analytical results can provide a basis for the development of the pipeline repair program.