Institute of Environmental Assessment and Water Research, IDAEA-CSIC, Barcelona, Catalunya 08034, Spain.
Associated Unit: Hydrogeology Group (UPC-CSIC), Spain; Dept. of Civil and Environmental Engineering, Universitat Politècnica de Catalunya, Barcelona, Spain.
Sci Total Environ. 2024 Nov 25;953:176078. doi: 10.1016/j.scitotenv.2024.176078. Epub 2024 Sep 5.
Soil Aquifer Treatment (SAT) is a robust technology to increase groundwater recharge and to improve reclaimed water quality. SAT reduces dissolved organic carbon, contaminants of emerging concern, nutrients, and colloidal matter, including pathogen indicators, but little is known about its ability to reduce loads of antibiotic resistance genes (ARGs) from reclaimed waters. Here we test six pilot SAT systems to eliminate various biological hazards from the secondary effluents of a wastewater treatment plant (WWTP), equipped with reactive barriers (RBs) including different sorptive materials. Using flow cytometry, qPCR and 16S rRNA gene amplicon sequencing methods, we determined that all six SAT systems reduced total loads of bacteria by 80 to 95 % and of clinically relevant ARGs by 85 to 99.9 %. These efficiencies are similar to those reported for UV/oxidation or membrane-based tertiary treatments, which require much more energy and resources. The presence and composition of reactive barriers, the season of sampling (June 2020, October 2020, and September 2021), or the flow regime (continuous versus pulsating) did not affect ARG removal efficiency, although they did alter the microbial community composition. This suggests that an adequate design of the SAT reactive barriers may significantly increase their performance. Under a mechanistic point of view, we observed an ecological succession of bacterial groups, linked to the changing physical-chemical conditions along the SAT, and likely correlated to the removal of ARGs. We concluded that SAT is as cost-efficient technology able to dramatically reduce ARG loads and other biological hazards from WWTP secondary effluents.
土壤含水层处理（Soil Aquifer Treatment，SAT）是一种增加地下水补给和改善再生水水质的强大技术。SAT 可降低溶解有机碳、新兴关注污染物、营养物质和胶体物质，包括病原体指标，但对于其降低再生水中抗生素抗性基因（Antibiotic Resistance Genes，ARGs）负荷的能力知之甚少。在这里，我们测试了六个试点 SAT 系统，以从污水处理厂（Wastewater Treatment Plant，WWTP）的二级出水去除各种生物危害，这些系统配备了包括不同吸附材料在内的反应性屏障（Reactive Barriers，RBs）。使用流式细胞术、qPCR 和 16S rRNA 基因扩增子测序方法，我们确定所有六个 SAT 系统将细菌总负荷降低了 80%至 95%，将临床相关 ARGs 降低了 85%至 99.9%。这些效率与紫外线/氧化或基于膜的三级处理相当，后者需要更多的能源和资源。反应性屏障的存在和组成、采样季节（2020 年 6 月、2020 年 10 月和 2021 年 9 月）或流动模式（连续与脉动）均不影响 ARG 去除效率，尽管它们确实改变了微生物群落组成。这表明，适当设计 SAT 反应性屏障可能会显著提高其性能。从机制角度来看，我们观察到细菌群体的生态演替，这与 SAT 沿程物理化学条件的变化有关，并且可能与 ARGs 的去除有关。我们得出结论，SAT 是一种具有成本效益的技术，能够显著降低 WWTP 二级出水中的 ARG 负荷和其他生物危害。
