Department of Civil and Environmental Engineering and Construction, University of Nevada Las Vegas (UNLV), 4505 Maryland Parkway, Las Vegas, NV, 89154-4015, USA.
Tetra Tech Inc, 720 Coleherne Road, Collierville, TN, 38017, USA.
Biodegradation. 2023 Aug;34(4):301-323. doi: 10.1007/s10532-022-10013-2. Epub 2023 Jan 4.
This research investigates the biodegradation of perchlorate in the presence of the co-contaminants nitrate and chlorate using soluble and slow-release carbon sources. In addition, the impact of bio-augmentation and dilution, which results in lower total dissolved salts (TDS) and contaminant levels, is examined. Laboratory microcosms were conducted using actual groundwater and soils from a contaminated aquifer. The results revealed that both soluble and slow-release carbon sources support biodegradation of contaminants in the sequence nitrate > chlorate > perchlorate. Degradation rates, including and excluding lag times, revealed that the overall impact of the presence of co-contaminants depends on degradation kinetics and the relative concentrations of the contaminants. When the lag time caused by the presence of the co-contaminants is considered, the degradation rates for chlorate and perchlorate were two to three times slower. The results also show that dilution causes lower initial contaminant concentrations, and consequently, slower degradation rates, which is not desirable. On the other hand, the dilution resulting from the injection of amendments to support remediation promotes desirably lower salinity levels. However, the salinity associated with the presence of sulfate does not inhibit biodegradation. The naturally occurring bacteria were able to support the degradation of all contaminants. Bio-augmentation was effective only in diluted microcosms. Proteobacteria and Firmicutes were the dominant phyla identified in the microcosms.
本研究采用可溶和缓释碳源，考察了共存硝酸盐和氯酸盐存在下，过氯酸盐的生物降解。此外，还考察了生物增强和稀释的影响，这会导致总溶解盐（TDS）和污染物水平降低。使用受污染含水层的实际地下水和土壤进行了实验室微宇宙实验。结果表明，可溶和缓释碳源都支持污染物的生物降解，降解顺序为硝酸盐>氯酸盐>高氯酸盐。包括和不包括滞后时间的降解速率表明，共存污染物的整体影响取决于降解动力学和污染物的相对浓度。当考虑共存污染物引起的滞后时间时，氯酸盐和高氯酸盐的降解速率会慢两到三倍。结果还表明，稀释会导致初始污染物浓度降低，从而导致降解速率降低，这是不理想的。另一方面，由于注入改良剂以支持修复而导致的稀释会促进令人期望的低盐度水平。然而，与硫酸盐存在相关的盐度不会抑制生物降解。自然存在的细菌能够支持所有污染物的降解。生物增强仅在稀释的微宇宙中有效。在微宇宙中鉴定到的优势菌门为变形菌门和厚壁菌门。
