Impacts of low-temperature thermal treatment on microbial detoxification of tetrachloroethene under continuous flow conditions

WATER RESEARCH

卷:145

Article

Marcet, Tyler F.¹  Capiro, Natalie L.¹  Yang, Yi²  Loffler, Frank E.^2,3,4,5,6  Pennell, Kurt D.^1,7 

[1] Tufts Univ, Dept Civil & Environm Engn, Medford, MA 02155 USA

[2] Univ Tennessee, Dept Civil & Environm Engn, Knoxville, TN 37996 USA

[3] Univ Tennessee, Dept Microbiol, Knoxville, TN 37996 USA

[4] Univ Tennessee, Dept Biosyst Engn & Soil Sci, Knoxville, TN 37996 USA

[5] Univ Tennessee, Ctr Environm Biotechnol, Knoxville, TN 37996 USA

[6] Oak Ridge Natl Lab, Biosci Div, Oak Ridge, TN 37831 USA

[7] Brown Univ, Sch Engn, Providence, RI 02912 USA

关键词: Chlorinated solvents;    Combined remedies;    Thermal treatment;    Bioremediation;    Microbial reductive dechlorination;    Reductive dehalogenase genes;    Dehalococcoides mccartyi;   

DOI  :  10.1016/j.watres.2018.07.076

来源: Elsevier

【 摘 要 】

Coupling in situ thermal treatment (ISTT) with microbial reductive dechlorination (MRD) has the potential to enhance contaminant degradation and reduce cleanup costs compared to conventional standalone remediation technologies. Impacts of low-temperature ISTT on Dehalococcoides mccartyi (Dhc), a relevant species in the anaerobic degradation of cis-1,2-dichloroethene (cis-DCE) and vinyl chloride (VC) to nontoxic ethene, were assessed in sand-packed columns under dynamic flow conditions. Dissolved tetrachloroethene (PCE; 258 +/- 46 mu M) was introduced to identical columns bioaugmented with the PCE-to-ethene dechlorinating consortium KB-1 (R). Initial column temperatures represented a typical aquifer (15 degrees C) or a site undergoing low-temperature MT (35 degrees C), and were subsequently increased to 35 and 74 degrees C, respectively, to assess temperature impacts on reductive dechlorination activity. In the 15 degrees C column, PCE was transformed primarily to cis-DCE (159 +/- 2 mu M), which was further degraded to VC (164 +/- 3 mu M) and ethene (30 +/- 0 mu M) within 17 pore volumes (PVs) after the temperature was increased to 35 degrees C. Regardless of the initial column temperature, ethene constituted >50 mol% of effluent degradation products in both columns after 73-74 PVs at 35 degrees C, indicating that MRD performance was greatly improved under low-temperature ISTT conditions. Increasing the temperature of the column initially at 35 degrees C resulted in continued VC and ethene production until a temperature of approximately 43 degrees C was reached, at which point Dhc activity substantially decreased. The abundance of the vcrA reductive dehalogenase gene exceeded that of the bvcA gene by 1-2.5 orders of magnitude at 15 degrees C, but this relationship inversed at temperatures >35 degrees C, suggesting Dhc strain-specific responses to temperature. These findings demonstrate improved MRD performance with low-temperature thermal treatment and emphasize potential synergistic effects at sites undergoing ISTT. (C) 2018 Elsevier Ltd. All rights reserved.

【 授权许可】

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