Betsholtz Alexander, Karlsson Stina, Svahn Ola, Davidsson Åsa, Cimbritz Michael, Falås Per
Department of Chemical Engineering, Lund University, 221 00 Lund, Sweden.
Sweden Water Research AB, Ideon Science Park, Scheelevägen 15, 223 70 Lund, Sweden.
Environ Sci Technol. 2021 Aug 17;55(16):11318-11327. doi: 10.1021/acs.est.1c02728. Epub 2021 Jul 26.
Granular activated carbon (GAC) filters can be used to reduce emissions of organic micropollutants via municipal wastewater, but it is still uncertain to which extent biological degradation contributes to their removal in GAC filters. C-labeled organic micropollutants were therefore used to distinguish degradation from adsorption in a GAC-filter media with associated biofilm. The rates and extents of biological degradation and adsorption were investigated and compared with other biofilm systems, including a moving bed biofilm reactor (MBBR) and a sand filter, by monitoring C activities in the liquid and gas phases. The microbial cleavage of ibuprofen, naproxen, diclofenac, and mecoprop was confirmed for all biofilms, based on the formation of CO, whereas the degradation of C-labeled moieties of sulfamethoxazole and carbamazepine was undetected. Higher degradation rates for diclofenac were observed for the GAC-filter media than for the other biofilms. Degradation of previously adsorbed diclofenac onto GAC could be confirmed by the anaerobic adsorption and subsequent aerobic degradation by the GAC-bound biofilm. This study demonstrates the potential use of C-labeled micropollutants to study interactions and determine the relative contributions of adsorption and degradation in GAC-based treatment systems.
颗粒活性炭（GAC）过滤器可用于减少城市污水中有机微污染物的排放，但生物降解在GAC过滤器中对其去除的贡献程度仍不确定。因此，使用碳-14标记的有机微污染物来区分GAC过滤介质及其相关生物膜中的降解和吸附。通过监测液相和气相中的碳-14活性，研究了生物降解和吸附的速率及程度，并与其他生物膜系统进行了比较，包括移动床生物膜反应器（MBBR）和砂滤器。基于二氧化碳的形成，证实了所有生物膜中布洛芬、萘普生、双氯芬酸和甲草胺的微生物裂解，而未检测到磺胺甲恶唑和卡马西平的碳-14标记部分的降解。观察到GAC过滤介质中双氯芬酸的降解速率高于其他生物膜。通过厌氧吸附以及随后GAC结合生物膜的好氧降解，可以证实先前吸附在GAC上的双氯芬酸的降解。本研究证明了碳-14标记的微污染物在研究相互作用以及确定基于GAC的处理系统中吸附和降解的相对贡献方面的潜在用途。
