Sustainable remediation: electrochemically assisted microbial dechlorination of tetrachloroethene‐contaminated groundwater

Abstract

Summary Microbial electric systems ( MESs ) hold significant promise for the sustainable remediation of chlorinated solvents such as tetrachlorethene (perchloroethylene, PCE ). Although the bio‐electrochemical potential of some specific bacterial species such as D ehalcoccoides and G eobacteraceae have been exploited, this ability in other undefined microorganisms has not been extensively assessed. Hence, the focus of this study was to investigate indigenous and potentially bio‐electrochemically active microorganisms in PCE ‐contaminated groundwater. Lab‐scale MESs were fed with acetate and carbon electrode/ PCE as electron donors and acceptors, respectively, under biostimulation ( BS ) and BS ‐bioaugmentation ( BS‐BA ) regimes. Molecular analysis of the indigenous groundwater community identified mainly S pirochaetes , F irmicutes , B acteroidetes , and γ and δ ‐ P roteobacteria . Environmental scanning electron photomicrographs of the anode surfaces showed extensive indigenous microbial colonization under both regimes. This colonization and BS resulted in 100% dechlorination in both treatments with complete dechlorination occurring 4 weeks earlier in BS‐BA samples and up to 11.5 μ A of current being generated. The indigenous non‐ D ehalococcoides community was found to contribute significantly to electron transfer with ∼61% of the current generated due to their activities. This study therefore shows the potential of the indigenous non‐ D ehalococcoides bacterial community in bio‐electrochemically reducing PCE that could prove to be a cost‐effective and sustainable bioremediation practice.

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Identifiers

DOI

10.1111/1751-7915.12089

Journal

Microbial Biotechnology

Year

2014