Rapid simultaneous biotransformation of perchloroethylene and chloroform at high groundwater concentrations

Anaerobic bioremediation of chlorinated solvents is a state-of-the-art technology. However, treatment of mixtures of chlorinated solvents at high concentrations is still a challenge. GreenSoil is carrying out an active remediation in the harbour of Tarragona, Spain, to stimulate the anaerobic biotransformation of perchloroethylene (PCE) and chloroform (CF) at concentrations up to 120 (PCE) and 350 mg/L (CF). The Laboratory of Microbiology (WUR) is carrying out research to verify the potential simultaneous biotransformation of PCE and CF at these high concentrations and to further investigate the micro-organisms involved.

Both PCE (81 mg/L) and CF (75 mg/L) were quickly degraded in microcosms set-up with groundwater from the site as apparent from the figure. Also after spiking with CF and PCE (indicated by the arrows), rapid degradation was observed. PCE was dechlorinated via vinyl chloride to ethylene. CF was dechlorinated to dichloromethane which was then further transformed to unidentified products. When the project will be resumed after relief of the Corona lockdown, we intend to further verify the completeness of CF biodegradation and to carry out (meta)genomic research to identify the microbes and enzymatic machinery involved.

Tom Bosma, Sjoerd Engelbertink, John Dijk, Hauke Smidt