Biocatalytic dechlorination of trichloroethylene with bio-palladium in a pilot-scale membrane reactor

Trichloroethylene (TCE) is a toxic and recalcitrant groundwater pollutant. An innovative technology using microbial produced Pd(0) nanoparticles for the remediation of TCE contaminated groundwater was developed. The nanoscale bio-Pd particles were precipitated on the biomass of Shewanella oneidensis and hydrogen gas, formate, or formic acid were used as hydrogen donors. Ethane turned out to be the only organic degradation product and no intermediate chlorinated reaction products were detected. Subsequently bio-Pd was implemented in a plate membrane reactor (MR) for the treatment of water containing TCE. In a continuous MR system, containing 50 mg L(-1) bio-Pd, removal rates up to 2,515 mg TCE day(-1) g(-1) Pd were achieved with H(2) gas as hydrogen donor. The measured chloride mass balance confirmed the removal rates. This work shows that a complete, efficient and rapid removal of TCE was achieved with bio-Pd and that a MR system containing bio-Pd and supplied with hydrogen gas offers an alternative for the current remediation technologies of water contaminated with TCE.