Supplemental data for the paper: Biodegradation and adsorption of micropollutants by biological activated carbon from a drinking water production plant

The presence of micropollutants in surface water is a potential threat for the production of high quality and safe drinking water. Adsorption of micropollutants onto granular activated carbon (GAC) in fixed-bed filters is often applied as a polishing step in the production of drinking water. Activated carbon can act as a carrier material for biofilm, hence biodegradation can be an additional removal mechanism for micropollutants in GAC filters. To assess the potential of biofilm to biodegrade micropollutants, it is necessary to distinguish adsorption from biodegradation as a removal mechanism. We performed experiments at 5 °C and 20 °C with biologically active and autoclaved GAC to assess the biodegradation of micropollutants by the biofilm grown on the GAC surface. Ten micropollutants were selected as model compounds. Three of them, iopromide, iopamidol and metformin, were biodegraded by the GAC biofilm. Additionally, we observed that temperature can increase or decrease adsorption, depending on the micropollutant studied. Finally, we compared the adsorption capacity of GAC used for more than 100,000 bed volumes and fresh GAC. We demonstrated that used GAC shows a higher adsorption capacity for guanylurea, metformin and hexamethylenetetramine and only a limited reduction in adsorption capacity for diclofenac and benzotriazole compared to fresh GAC.

地表水中微污染物（micropollutants）的存在，对高品质安全饮用水的生产构成潜在威胁。在固定床过滤器中，将微污染物吸附于颗粒活性炭（granular activated carbon, GAC）之上，常被用作饮用水生产中的深度净化工序。活性炭可作为生物膜的载体基质，因此生物降解可成为GAC过滤器中微污染物的额外去除机制。为评估生物膜对微污染物的生物降解潜力，有必要将吸附与生物降解这两种去除机制区分开来。我们分别在5℃与20℃条件下，采用生物活性及高压灭菌处理的GAC开展实验，以探究生长于GAC表面的生物膜对微污染物的生物降解效果。本次研究选取10种微污染物作为模型化合物，其中碘普罗胺（iopromide）、碘帕醇（iopamidol）及二甲双胍（metformin）这3种物质可被GAC生物膜降解。此外我们观察到，温度对吸附作用的影响因微污染物种类而异，可表现为促进或抑制吸附。最后，我们对比了累计运行超过10万床体积的老化GAC与全新GAC的吸附性能。结果表明，与全新GAC相比，老化GAC对胍基脲（guanylurea）、二甲双胍及六亚甲基四胺（hexamethylenetetramine）的吸附能力更高，而对双氯芬酸（diclofenac）与苯并三氮唑（benzotriazole）的吸附能力仅出现小幅下降。