Wet weather behavior of unregulated pollutants and pathogens in combined sewer network

本研究的目的是揭示潮湿的天气行为的不受管制的微污染物和病原体来自合流污水溢流（CSO）。详细的现场调查进行了表征的污染物负荷的日变化，粒径分布，醌剖面悬浮微生物，健康相关的微生物，包括病毒和微污染物，如抗生素。日变化分为几种模式依赖于污染源。抗生素浓度的变化似乎反映了每种抗生素的代谢和排泄特性。为了研究潮湿天气条件下管道沉积物的再悬浮现象，通过将清水从水车注入上游检修孔来模拟雨水径流。针对下游管道中细菌负荷与病毒负荷变化规律不同的问题，建立了合流制管网中泥沙分布的数学模型，并提出了优先清洗管道的方案。模型模拟结果表明，通过对沉积物集中的管道进行清洗，可以有效降低CSO污染负荷，并提出了使CSO污染负荷最小化的污水系统运行算法。通过参考上游管道的实测水质值，对一个简单的自回归水质在线预测模型进行了修正。改进了水流预报模型，以更好地模拟中小尺度降雨过程中CSO的发生。讨论了该算法在真实的时间控制系统中的应用前景。

The aim of this research project was to unveil the wet weather behavior of unregulated micropollutants and pathogens derived from combined sewer overflow (CSO). Detailed field survey was conducted to characterize the diurnal variation of the pollutant loads, particle size distribution, quinone profile of suspended microbes, health related microorganisms including viruses and micropollutants such as antibiotics. The diurnal variation was categorized into several patterns dependent on the pollutant source. The variation of antibiotics concentration seemed to reflect the metabolism and excretion characteristics of each antibiotic.To investigate the phenomenon of resuspension of pipe sediment under wet weather condition, the rainwater runoff was simulated by pouring clean water into an upstream manhole from a water wagon. Loads of bacteria in the downstream pipe exhibited a different varying pattern from that of viruses.A mathematical modeling was conducted to evaluate the sediment distribution in a combined sewer network and then a protocol to distinguish the priority pipes for cleaning was proposed. A model simulation revealed that cleaning of pipes which specifically accumulated sediments was effective for reducing the CSO pollutant load.Algorithm of sewer system operation to minimize the CSO pollutant load was developed. A simple auto-regression model for on-line water quality prediction was modified with referring a measured water quality value in an upstream pipe. Water flow prediction model was refined to provide a better simulation of CSO occurrence at medium- and small-size rainfall events. Future application of the algorithm to a real time control system for CSO management was discussed.