Monash Water for Liveability, Department of Civil Engineering, Monash University, Wellington Rd, Clayton, Victoria, 3800, Australia,
Environ Sci Pollut Res Int. 2014 Apr;21(8):5391-401. doi: 10.1007/s11356-013-2430-2. Epub 2013 Dec 27.
Biofilters are widely adopted in Australia for stormwater treatment, but the reported removal of common faecal indicators (such as Escherichia coli (E. coli)) varies from net removal to net leaching. Currently, the underlying mechanisms that govern the faecal microbial removal in the biofilters are poorly understood. Therefore, it is important to study retention and subsequent survival of faecal microorganisms in the biofilters under different biofilter designs and operational characteristics. The current study investigates how E. coli survival is influenced by temperature, moisture content, sunlight exposure and presence of other microorganisms in filter media and top surface sediment. Soil samples were taken from two different biofilters to investigate E. coli survival under controlled laboratory conditions. Results revealed that the presence of other microorganisms and temperature are vital stressors which govern the survival of E. coli captured either in the top surface sediment or filter media, while sunlight exposure and moisture content are important for the survival of E. coli captured in the top surface sediment compared to that of the filter media. Moreover, increased survival was found in the filter media compared to the top sediment, and sand filter media was found be more hostile than loamy sand filter media towards E. coli survival. Results also suggest that the contribution from the tested environmental stressors on E. coli survival in biofilters will be greatly affected by the seasonality and may vary from one site to another.
生物过滤器在澳大利亚被广泛应用于雨水处理，但据报道，常见粪便指标（如大肠杆菌（E. coli））的去除率从净去除到净浸出不等。目前，控制生物过滤器中粪便微生物去除的潜在机制还不甚清楚。因此，研究在不同生物过滤器设计和操作特性下，粪便微生物在生物过滤器中的保留和随后的生存情况非常重要。本研究探讨了温度、含水量、阳光暴露以及过滤介质和顶部表面沉积物中其他微生物的存在对大肠杆菌存活的影响。从两个不同的生物过滤器中采集土壤样本，在受控的实验室条件下研究大肠杆菌的存活情况。结果表明，其他微生物的存在和温度是控制在顶部表面沉积物或过滤介质中捕获的大肠杆菌存活的重要胁迫因素，而阳光暴露和含水量对在顶部表面沉积物中捕获的大肠杆菌的存活比对过滤介质中的存活更为重要。此外，与顶部沉积物相比，在过滤介质中发现了更多的存活，并且砂质过滤介质比粉质砂质过滤介质对大肠杆菌的存活更具敌意。研究结果还表明，受测试环境胁迫因素对生物过滤器中大肠杆菌存活的影响将受到季节性的极大影响，并且可能因地点而异。
