Department of Mathematical Sciences and Technology, Norwegian University of Life Sciences, 1430 Ås, Norway E-mail:
Water Sci Technol. 2020 Oct;82(7):1312-1326. doi: 10.2166/wst.2020.395.
The Municipality of Asker (Norway) is at risk of not meeting the water quality targets set by the European Union Water Framework Directive within the stipulated timeframe. While there are multiple factors negatively impacting water quality in the municipality, wastewater is likely to be a major contributor. Infiltration and inflow water (I/I-water) leads to a number of unwanted consequences, of which direct discharge of untreated wastewater through overflow points is particularly important. In Aker municipality the portion of I/I-water is about 63%, while the goal is to achieve a level of about 30%. This study utilises a socio-economic cost-effectiveness analysis of measures to prevent sewer overflows into waterbodies. The most effective alternative identified in the analysis is a complete renovation of old pipes in combination with troubleshooting for faulty stormwater connections, when compared to alternatives considering upsizing/retention. I/I-water cost the municipality of Asker NOK34 million in 2017, when using a price of NOK16,434 for each kg of total phosphorus (Tot-P) let into the recipient water bodies. If the phosphorus cost is equal to or less than NOK17,806/kg Tot-P, then it will not be socio-economically justified to reduce I/I-water.
挪威阿斯克市有可能无法在规定时间内达到欧盟水框架指令设定的水质目标。尽管有许多因素对该市的水质产生负面影响，但废水很可能是一个主要因素。渗透和流入水（I/I 水）导致了许多不良后果，其中通过溢流水道直接排放未经处理的废水尤为重要。在阿斯克市，I/I 水的比例约为 63%，而目标是将其降低到 30%左右。本研究利用社会经济成本效益分析方法，对防止污水管溢出到水体中的措施进行了评估。在分析中，确定最有效的替代方案是对旧管道进行全面翻新，并对故障雨水连接进行故障排除，而不是考虑扩大/保留规模的替代方案。2017 年，阿斯克市因 I/I 水而损失了 3400 万挪威克朗，假设每公斤总磷（Tot-P）进入受纳水体的成本为 16434 挪威克朗，则如果磷的成本等于或低于 17806 挪威克朗/公斤 Tot-P，则减少 I/I 水在社会经济上是不合理的。
