University of Maryland, Department of Civil and Environmental Engineering, 1153 Glenn L. Martin Hall, College Park, MD, 20740, USA.
Resphera Biosciences LLC, Baltimore, MD, USA.
Chemosphere. 2023 May;323:138059. doi: 10.1016/j.chemosphere.2023.138059. Epub 2023 Feb 18.
Many groundwater aquifers around the world are contaminated with trichloroethene (TCE), which can be harmful to human and ecosystem health. Permeable Reactive Barriers (PRB) are commonly used to remediate TCE-contaminated groundwaters especially when a point source is ill defined. Using biosolids from wastewater treatment plants as a PRB filling material can provide a source of carbon and nutrients for dechlorinating bacterial activity. However, under the anaerobic conditions of the PRB, methanogenesis can also occur which can adversely affect reductive dechlorination. We conducted bench scale experiments to evaluate the effect of biosolids on TCE reductive dechlorination and found that methanogenesis was significantly higher in the reactors amended with biosolids, but that reductive dechlorination did not decrease. Furthermore, the microbial communities in the biosolid-enhanced reactors were more abundant with obligate dechlorinators, such as Dehalobacter and Dehalogenimonas, than the reactors amended only with the dechlorinating culture. The biosolids enhanced the presence and abundance of methanogens and acetogens, which had a positive effect on maintaining an efficient dechlorinating microbial community and provided the necessary enzymes, cofactors, and electron donors. These results indicate that waste materials such as biosolids can be turned into a valuable resource for bioremediation of TCE and likely other contaminants.
世界上许多地下水含水层都受到三氯乙烯（TCE）的污染，这可能对人类和生态系统健康造成危害。可渗透反应屏障（PRB）通常用于修复 TCE 污染的地下水，特别是当污染源不明确时。利用废水处理厂的生物固体作为 PRB 填充材料，可以为脱氯细菌的活动提供碳源和营养物质。然而，在 PRB 的厌氧条件下，产甲烷作用也可能发生，这会对还原脱氯产生不利影响。我们进行了台架规模的实验来评估生物固体对 TCE 还原脱氯的影响，结果发现，添加生物固体的反应器中产甲烷作用明显更高，但还原脱氯并没有减少。此外，与仅添加脱氯培养物的反应器相比，生物固体增强反应器中的微生物群落中具有强制性脱氯菌，如脱硫弧菌属和脱硫单胞菌属的数量更多。生物固体增强了产甲烷菌和产乙酸菌的存在和丰度，这对维持高效的脱氯微生物群落具有积极作用，并提供了必要的酶、辅助因子和电子供体。这些结果表明，像生物固体这样的废物可以转化为 TCE 和可能其他污染物生物修复的有价值资源。
