Eawag: Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland.
Eawag: Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland; Department of Environmental Systems Science, ETH, Zürich, Switzerland.
Water Res. 2022 Oct 15;225:119119. doi: 10.1016/j.watres.2022.119119. Epub 2022 Sep 14.
Effluents of wastewater treatment plants can impact microbial communities in the receiving streams. However, little is known about the role of microorganisms in wastewater as opposed to other wastewater constituents, such as nutrients and micropollutants. We aimed therefore at determining the impact of wastewater microorganisms on the microbial diversity and function of periphyton, key microbial communities in streams. We used a flow-through channel system to grow periphyton upon exposure to a mixture of stream water and unfiltered or ultra-filtered wastewater. Impacts were assessed on periphyton biomass, activities and tolerance to micropollutants, as well as on microbial diversity. Our results showed that wastewater microorganisms colonized periphyton and modified its community composition, resulting for instance in an increased abundance of Chloroflexi and a decreased abundance of diatoms and green algae. This led to shifts towards heterotrophy, as suggested by the changes in nutrient stoichiometry and the increased mineralization potential of carbon substrates. An increased tolerance towards micropollutants was only found for periphyton exposed to unfiltered wastewater but not to ultra-filtered wastewater, suggesting that wastewater microorganisms were responsible for this increased tolerance. Overall, our results highlight the need to consider the role of wastewater microorganisms when studying potential impacts of wastewater on the receiving water body.
污水处理厂的废水会对受纳河流中的微生物群落产生影响。然而，人们对微生物在废水中的作用知之甚少，而对营养物和微污染物等其他废水成分的作用却了解较多。因此，我们旨在确定废水微生物对溪流中关键微生物群落——周丛生物多样性和功能的影响。我们使用流动通道系统，在暴露于混合的溪流水和未经过滤或超滤的废水的情况下，使周丛生物生长。我们评估了废水微生物对周丛生物生物量、活性和对微污染物的耐受性以及微生物多样性的影响。我们的结果表明，废水微生物会在周丛生物上定殖并改变其群落组成，例如增加绿弯菌门（Chloroflexi）的丰度和减少硅藻和绿藻的丰度。这导致了向异养的转变，这可以从营养化学计量的变化和碳基质的矿化潜力的增加中得到证明。仅在暴露于未经过滤的废水中的周丛生物中发现对微污染物的耐受性增加，而在暴露于超滤的废水中的周丛生物中没有发现，这表明是废水微生物导致了这种增加的耐受性。总的来说，我们的研究结果强调了在研究废水对受纳水体的潜在影响时，需要考虑废水微生物的作用。
