Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
J Hazard Mater. 2023 Mar 5;445:130637. doi: 10.1016/j.jhazmat.2022.130637. Epub 2022 Dec 23.
Extending the lifetime of granular activated carbon (GAC) filters with no significant loss in their effectiveness is a considerable challenge for drinking water supply utilities. However, the effects of residual Al from coagulants on GAC performance are rarely considered. Herein, in-service GAC samples obtained from full-scale water treatment plants were investigated to evaluate the amount of accumulated Al. Although the Al concentration in water was two to three times lower than the Ca concentration, Al exhibited considerable accumulation (second to Ca accumulation) in in-service GAC samples (0.68-8.63 mg g). Surface characterization results indicated that Al accumulation could have been caused by the co-precipitation of Al with Ca and Si to form CaAlSiO·HO and CaAlOSO, self-precipitation or complexion with -OH/-COOH on the GAC or biofilm surfaces. Correlation analysis of the accumulated Al and GAC properties implied that Al accumulation considerably reduced the surface area of GAC by ∼30%. Lab simulation experiments indicated that the removal of dissolved organic matter was reduced by 6-10% when additional Al was loaded. In addition, results showed that the residual Al (up to 200 μg L) considerably affected the extracellular polymeric substance component and microorganism community structure. In summary, strict control of residual Al is beneficial for maintaining the efficacies of GAC and biologically activated carbon.
延长颗粒活性炭 (GAC) 过滤器的使用寿命而不显著降低其效率，这对饮用水供应设施来说是一个相当大的挑战。然而，很少有人考虑到混凝剂中的残留铝对 GAC 性能的影响。在此，研究了从全规模水处理厂获得的在用 GAC 样品，以评估累积的 Al 量。尽管水中的 Al 浓度比 Ca 浓度低两到三倍，但 Al 在在用 GAC 样品中（0.68-8.63mg g）的积累量相当可观（仅次于 Ca 的积累量）。表面特性结果表明，Al 的积累可能是由于 Al 与 Ca 和 Si 共沉淀形成 CaAlSiO·HO 和 CaAlOSO，或在 GAC 或生物膜表面的自沉淀或络合 -OH/-COOH 造成的。累积 Al 与 GAC 特性的相关分析表明，Al 积累使 GAC 的表面积减少了约 30%。实验室模拟实验表明，当负载额外的 Al 时，溶解有机物的去除率降低了 6-10%。此外，结果表明，残留的 Al（高达 200μg L）会对细胞外聚合物成分和微生物群落结构产生很大的影响。总之，严格控制残留的 Al 有利于维持 GAC 和生物活性炭的效率。
