Key Laboratory of Marine Environment Science and Ecology, Ministry of Education and College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China; Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering, Ocean University of China, Qingdao, 266100, China; Key Laboratory of Groundwater Conservation of MWR, China University of Geosciences, Beijing, 100083, China.
Key Laboratory of Marine Environment Science and Ecology, Ministry of Education and College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China; Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering, Ocean University of China, Qingdao, 266100, China.
J Environ Manage. 2023 Nov 1;345:118635. doi: 10.1016/j.jenvman.2023.118635. Epub 2023 Jul 26.
The prevention and treatment of bioclogging is of great significance to the application of Managed Aquifer Recharge (MAR). This study investigated the alleviating effect of biosurfactant rhamnolipid (RL) on bioclogging by laboratory-scale percolation experiments. The results show that the addition of RL greatly reduced bioclogging. Compared with the group without RL, the relative hydraulic conductivity (K') of the 100 mg/L RL group increased 5 times at the end of the experiment (23 h), while the bacterial cell amount and extracellular polymeric substances (EPS) content on the sand column surface (0-2 cm) decreased by 60.8% and 85.7%, respectively. In addition, the richness and diversity of the microbial communities within the clogging matter decreased after the addition of RL. A variety of bacterial phyla were found, among which Proteobacteria were predominant in all groups. At the genus level, RL reduced the relative abundance of Acinetobacter, Bacillus, Klebsiella, and Pseudomonas. These microbes are known as strong adhesion, large size, and easy to form biofilms, therefore playing a critical role during MAR bioclogging. Moreover, RL changed the surface properties of bacteria and porous media, which results in the increase of electrostatic repulsion and decrease of hydrophobic interaction between them. Therefore, RL mediated the bacteria-porous media interaction to reduce biomass in porous media, thereby alleviating bioclogging. This study implies that RL's addition is an environmentally friendly and effective method to alleviate the bioclogging in MAR.
生物堵塞的防治对含水层人工补给（MAR）的应用具有重要意义。本研究通过实验室规模的渗流实验，研究了生物表面活性剂鼠李糖脂（RL）对生物堵塞的缓解作用。结果表明，RL 的添加大大减轻了生物堵塞。与未添加 RL 的组相比，在实验结束时（23 小时），添加 100mg/L RL 的组的相对水力传导率（K'）增加了 5 倍，而沙柱表面（0-2cm）上的细菌数量和胞外聚合物（EPS）含量分别减少了 60.8%和 85.7%。此外，添加 RL 后，堵塞物内微生物群落的丰富度和多样性降低。发现了多种细菌门，其中所有组都以变形菌门为主。在属水平上，RL 降低了不动杆菌属、芽孢杆菌属、克雷伯氏菌属和假单胞菌属的相对丰度。这些微生物由于具有较强的粘附性、较大的尺寸和易于形成生物膜而著称，因此在 MAR 生物堵塞中起着关键作用。此外，RL 改变了细菌和多孔介质的表面性质，导致它们之间的静电排斥增加，疏水性相互作用减少。因此，RL 介导了细菌-多孔介质相互作用，减少了多孔介质中的生物量，从而缓解了生物堵塞。本研究表明，添加 RL 是一种缓解 MAR 中生物堵塞的环保且有效的方法。
