Aarhus University, Dept. Environmental Science, Section for Environmental Microbiology & Biotechnology, Roskilde, Denmark.
Aalborg University, Dept. of Chemistry and Bioscience/Section of Chemical Engineering, Esbjerg, Denmark.
Sci Total Environ. 2019 Dec 1;694:133710. doi: 10.1016/j.scitotenv.2019.133710. Epub 2019 Aug 1.
Groundwater extracted for drinking water production is commonly treated by aeration and sand filtration. However, this simple treatment is typically unable to remove pesticide residues. As a solution, bioaugmentation of sand filter units (i.e., the addition of specific degrader strains) has been proposed as an alternative "green" technology for targeted pesticide removal. However, the introduced degraders are challenged by (i) micropollutant levels of target residue, (ii) the oligotrophic environment and (iii) competition and predation by the native microorganisms, leading to loss of population and degradation potential. To overcome these challenges, we propose the introduction of a novel hybrid treatment step to the overall treatment process in which reverse osmosis filtration and biodegradation are combined to remove a target micropollutant. Here, the reverse osmosis produces a concentrated retentate that will act as a feed to a dedicated biofilter unit, intended to promote biodegradation potential and stability of an introduced degrader. Subsequently, the purified retentate will be re-mixed with the permeate from reverse osmosis, for re-mineralization and downstream consumption. In our study, we investigated the effect of reverse osmosis retentates on the degradation potential of an introduced degrader. This paper provides the first promising results of this hybrid concept using the 2,6-dichlorobenzamide (BAM)-degrading bacteria Aminobacter sp. MSH1 in batch experiments, spiked with radiolabeled BAM. The results showed an increased degradation potential of MSH1 in retentate waters versus untreated water. Colony-forming units and qPCR showed a stable MSH1 population, despite higher concentrations of salts and metals, and increased growth of native bacteria.
地下水通常经过曝气和砂滤处理后用于饮用水生产。然而，这种简单的处理方法通常无法去除农药残留。作为一种解决方案，砂滤单元的生物增强（即添加特定的降解菌株）已被提议作为一种替代的“绿色”技术，用于有针对性地去除农药。然而，引入的降解菌面临着以下挑战：(i)目标残留的微量污染物水平；(ii)贫营养环境；(iii)土著微生物的竞争和捕食，导致种群和降解潜力的丧失。为了克服这些挑战，我们提出在整个处理过程中引入一种新的混合处理步骤，即将反渗透过滤和生物降解结合起来去除目标微量污染物。在这里，反渗透会产生浓缩的截留物，作为专用生物滤池单元的进料，旨在促进引入的降解菌的生物降解潜力和稳定性。随后，净化后的截留物将与反渗透的渗透物重新混合，用于再矿化和下游消费。在我们的研究中，我们研究了反渗透截留物对引入的降解菌降解潜力的影响。本文首次提供了使用 2,6-二氯苯甲酰胺（BAM）降解菌 Aminobacter sp. MSH1 进行批处理实验的混合概念的有希望的结果，实验中用放射性标记的 BAM 进行了处理。结果表明，与未处理水相比，MSH1 在截留物水中的降解潜力增加。尽管盐度和金属浓度较高，以及土著细菌的生长增加，但菌落形成单位和 qPCR 显示 MSH1 种群稳定。
