Simultaneous anaerobic transformation of tetrachloroethene and carbon tetrachloride in a continuous flow column.
In: Journal of Contaminant Hydrology, Jg. 190 (2016-07-01), S. 58-68
academicJournal
Zugriff:
Tetrachloroethene (PCE) and carbon tetrachloride (CT) were simultaneously transformed in a packed column that was bioaugmented with the Evanite culture (EV). The data presented here have been obtained over a period of 1930 days. Initially the column was continuously fed synthetic groundwater with PCE (0.1 mM), sulfate (SO 4 2 − ) (0.2 mM) and formate (2.1 mM) or lactate (1.1 mM), but not CT. In these early stages of the study the effluent H 2 concentrations ranged from 7 to 19 nM, and PCE was transformed to ethene (ETH) (81 to 85%) and vinyl chloride (VC) (11 to 17%), and SO 4 2 − was completely reduced when using either lactate or formate as electron donors. SO 4 2 − reduction occurred concurrently with cis-DCE and VC dehalogenation. Formate was a more effective substrate for promoting dehalogenation based on electron donor utilization efficiency. Simultaneous PCE and CT tests found CT (0.015 mM) was completely transformed with 20% observed as chloroform (CF) and trace amounts of chloromethane (CM) and dichloromethane (DCM), but no methane (CH 4 ) or carbon disulfide (CS 2 ). PCE transformation to ETH improved with CT addition in response to increases in H 2 concentrations to 160 nM that resulted from acetate formation being inhibited by either CT or CF. Lactate fermentation was negatively impacted after CT transformation tests, with propionate accumulating, and H 2 concentrations being reduced to below 1 nM. Under these conditions both SO 4 2 − reduction and dehalogenation were negatively impacted, with sulfate reduction not occurring and PCE being transformed to cis-dichloroethene (c-DCE) (52%) and VC (41%). Upon switching to formate, H 2 concentrations increased to 40 nM, and complete SO 4 2 − reduction was achieved, while PCE was transformed to ETH (98%) and VC (1%), with no acetate detected. Throughout the study PCE dehalogenation to ethene was positively correlated with the effluent H 2 concentrations. [ABSTRACT FROM AUTHOR]
Titel: |
Simultaneous anaerobic transformation of tetrachloroethene and carbon tetrachloride in a continuous flow column.
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Autor/in / Beteiligte Person: | Azizian, Mohammad F. ; Semprini, Lewis |
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Zeitschrift: | Journal of Contaminant Hydrology, Jg. 190 (2016-07-01), S. 58-68 |
Veröffentlichung: | 2016 |
Medientyp: | academicJournal |
ISSN: | 0169-7722 (print) |
DOI: | 10.1016/j.jconhyd.2016.04.002 |
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