IMDEA Water, Avenida Punto Com 2, E-28805 Madrid, Spain; Alcalá University, Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, E-28871 Madrid, Spain.
Carlos III University, Department of Bioengineering, E-28911 Madrid, Spain.
Sci Total Environ. 2023 Apr 20;870:161890. doi: 10.1016/j.scitotenv.2023.161890. Epub 2023 Jan 31.
As non-conventional wastewater treatment, vegetation filters make the most of the natural attenuation processes that occur in soil to remove contaminants, while providing several environmental benefits. However, this practice may introduce contaminants of emerging concern (CECs) and their transformation products (TPs) into the environment. A potential improvement to the system was tested using column experiments containing soil (S) and soil amended with woodchips (SW) or biochar (SB) irrigated with synthetic wastewater that included 11 selected CECs. This study evaluated: i) known CECs attenuation and ii) unknown metabolites formation. Known CECs attenuation was assessed by total mass balance by considering both water and soil media. An untargeted metabolomic strategy was developed to assess the formation of unknown metabolites and to identify them in water samples. The results indicated that SB enhanced CECs attenuation and led to the formation of fewer metabolites. Sorption and biodegradation processes were favored by the bigger surface area of particles in SB column, especially for compounds with negative charges. Incorporating woodchips into soil shortened retention times in the column, which reduced attenuation phenomena and resulted in the formation of significantly more metabolites. Incomplete biodegradation reactions, fostered by shorter retention times in SW column could mainly explain these results.
作为非传统的废水处理方法，植被过滤器充分利用土壤中发生的自然衰减过程来去除污染物，同时提供了多种环境效益。然而，这种做法可能会将新出现的关注污染物（CECs）及其转化产物（TPs）引入环境中。本研究通过含有土壤（S）和用木屑（SW）或生物炭（SB）改良的土壤的柱实验来测试该系统的潜在改进，用含有 11 种选定的 CECs 的合成废水灌溉。本研究评估了：i）已知 CECs 的衰减和 ii）未知代谢物的形成。通过考虑水和土壤介质的总质量平衡来评估已知 CECs 的衰减。开发了一种非靶向代谢组学策略来评估未知代谢物的形成并在水样中识别它们。结果表明，SB 增强了 CECs 的衰减，并导致形成的代谢物更少。SB 柱中颗粒更大的表面积有利于吸附和生物降解过程，尤其是对带负电荷的化合物。将木屑掺入土壤中会缩短柱中的保留时间，从而减少衰减现象，并导致形成的代谢物明显增多。SW 柱中较短的保留时间促进了不完全的生物降解反应，这主要可以解释这些结果。
