Remediation of Cr (VI): soil flushing combined with enhanced bioremediation
04 February 2021
Hexavalent chromium or Cr (VI) is a highly mobile and toxic contaminant that cannot be degraded. However, it can be transformed to the less toxic and less mobile form, Cr (III). By stimulating sulphate reduction, Cr(VI) will be reduced to Cr(III) and forms insoluble precipitates.
Based on the promising laboratory results of a leaching tests, GreenSoil implemented a soil flushing plan, followed by (bio)precipitation, for the remediation of Cr (VI) within an anaerobic enhanced bioremediation system.
Monitoring events, following the flushing of contaminated soil and injection of electron-donor (Dehalo-GS), showed that Cr (VI) and total Cr concentrations were rapidly and strongly reduced (>90%) within 5 months.
It could be demonstrated that Cr (VI) was being reduced to Cr (III) during the process and that, on average, about 82% of the final total Cr concentration consisted of Cr (III) (vs 11% before the field test).