Abstract:

Urban stormwater, as a new renewable water source, has received a wide attention. Microbial pollutants present in stormwater is one of the biggest issues threatening stormwater reuse safety. The variability of water quality and bacterial reactivation during the stormwater storage can result in high risk for stormwater reuse safety. However, knowledge of the quality variation of stormwater under different storage conditions is limited. In this context, this study explored the water quality variations, and the regeneration of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) to analyse stormwater reuse safety under two different storage processes, namely, sealed and open storage. The results indicated that though there was a high variability in stormwater quality parameters during both sealed storage and open storage processes, relatively lower variations of water quality were confirmed in sealed storage process due to the limited influence of surrounding environments. For example, compared to open storage, the concentration of stormwater quality indicators such as UV₂₅₄, TOC, turbidity and NH₄⁺-N in sealed storage showed a decreased trend over the storage time. But regarding to the bacterial reactivation rate, higher values were found in sealed storage type. Meanwhile, S. aureus had a higher reactivation rate than E. coli during sealed storage process. Hence, our results indicated that to ensure the safety of stormwater reuse, the attention should be paid to the storage types and bacteria species while effective and appropriate treatment measures should be taken as well.

Key words: stormwater quality, stormwater reuse, stormwater storage, Escherichia coli, Staphylococcus aureus, water quality indicator

摘要：

城市雨水作为一种可回用的新兴水源，近年来受到学者们的广泛关注。雨水在储存过程中存在水质变化和细菌复活的可能性，是保障雨水回用安全面临的最大风险因素之一。但目前关于不同储存方式下，雨水水质变化规律的研究仍十分有限。据此，以屋顶雨水为对象，采用大肠杆菌（E. coli）和金黄色葡萄球菌（S. aureus）作为雨水中典型病原微生物代表，探究了屋顶雨水在密封式和开放式两种不同储存方式下水质变化规律和细菌再生情况，以期为保障储存雨水的回用安全提供科学依据和技术指导。研究结果表明，尽管两种储存方式下的雨水水质参数变异性较大，但密封式储存下的雨水由于受外界环境的干扰低，因此水质波动变化较开放式储存小。具体表现为密封式储存条件下，水质指标如UV₂₅₄、TOC、浊值度及NH₄⁺-N等参数随储存时间的延长呈降低趋势。然而，从细菌复活情况来看，密封式储存下雨水具有更高的细菌复活率，且金黄色葡萄球菌相比大肠杆菌显著复活。因此，为了确保雨水回用安全性，有必要考虑不同储存方式对水质和细菌生长的影响，以及细菌种类对水质变化的影响，以此采取针对性的措施对储存雨水进行再次处理。

关键词: 雨水水质, 雨水回用, 雨水储存, 大肠杆菌, 金黄色葡萄球菌, 水质指标