Meng Qingling, Shi Fuqiang, Zhong Peng, Fan Wei, Xue Honghai, Jiang Yan
Key Laboratory of Songliao Aquatic Environment, Ministry of Education, Jilin Jianzhu University, Changchun 130118, China E-mail:
Key Laboratory of Songliao Aquatic Environment, Ministry of Education, Jilin Jianzhu University, Changchun 130118, China.
Water Sci Technol. 2023 Jul;88(2):443-453. doi: 10.2166/wst.2023.213.
Artificial groundwater recharge with reclaimed water (secondary effluent from wastewater treatment plants) has become an important approach to solving water scarcity worldwide. Microorganisms in activated sludge can secrete many extracellular polymeric substances (EPS). However, information on the impact of EPS on the movement of heavy metals in porous media and their environmental effects on underground networks is limited. To assess this risk, we extracted EPS from the aerobic section of a wastewater treatment plant using hot sodium hydroxide and conducted experiments using one-dimensional sand columns to investigate how ion composition and strength affect the movement and interaction of cadmium (Cd) and EPS in porous media. The results showed that EPS facilitated Cd migration in porous media. Sodium (Na) and calcium (Ca) ions promoted the migration of Cd in porous media and EPS-Cd complexation. The effect of Ca was more significant than that of Na. As the Na adsorption ratio increased, the migration ability of Cd in porous media and the complexation ability of EPS with Cd decreased. Therefore, when estimating the migration of EPS and Cd in subsurface environments, careful consideration should be given to prevent the risk of groundwater pollution.
利用再生水（污水处理厂的二级出水）进行人工地下水回灌已成为解决全球水资源短缺的重要途径。活性污泥中的微生物能分泌多种胞外聚合物（EPS）。然而，关于EPS对重金属在多孔介质中迁移的影响及其对地下管网的环境效应的信息有限。为评估这种风险，我们用热氢氧化钠从污水处理厂的好氧段提取了EPS，并使用一维砂柱进行实验，以研究离子组成和强度如何影响镉（Cd）和EPS在多孔介质中的迁移及相互作用。结果表明，EPS促进了Cd在多孔介质中的迁移。钠（Na）和钙（Ca）离子促进了Cd在多孔介质中的迁移以及EPS-Cd络合。Ca的作用比Na更显著。随着Na吸附率的增加，Cd在多孔介质中的迁移能力以及EPS与Cd的络合能力下降。因此，在评估EPS和Cd在地下环境中的迁移时，应谨慎考虑以防止地下水污染风险。
