In-situ anaerobic bioremediation of groundwater in Shropshire
Contract period: 12 months
A persistent plume of chlorinated solvents, principally tetrachlorothene (PCE), was present underneath the floor of this busy manufacturing site. The average PCE concentration in the groundwater was 6,900 µg/l with a maximum of 33,000 µg/l. Following small scale laboratory testing, Telluric Land Remediation proposed in-situ anaerobic bioremediation using DCL Biosolv.
DCL Biosolv was first diluted with water, using a mobile dilution / injection unit, and then gravity fed to 34 previously installed boreholes. A total volume of 9,500 litres was injected containing 1,150 kg of DCL Biosolv, over a period of four days.
Following the product injection works, groundwater was monitored and sampled to assess the progress of remediation. Parameters monitored include soil gas concentrations, groundwater level, conductivity, oxidation-reduction potential, dissolved oxygen and pH. Groundwater samples were recovered for analysis by an independent accredited laboratory.
Monitoring results showed rapid onset of conditions required for reductive dehalogenation of PCE and associated chlorinated solvent contaminants. Groundwater sampling 13 weeks after injection of DCL Biosolv showed 98% reduction in PCE and 60% reduction in trichloroethene, to below their respective target concentrations. Further confirmatory groundwater monitoring and sampling were undertaken quarterly for 12 months which proved contaminant concentrations remained well below their required target concentrations.
- Design of bioremediation system
- In situ treatment of tetrachloroethene (PCE) contamination in soil and groundwater
- Design of remediation system
- Injection of 9,500 litres of diluted DCL Biosolv
- Installation of groundwater monitoring boreholes
- Quarterly groundwater sampling and monitoring
- Progress reports and compilation of final validation report
The selected remediation strategy proved to be a cost effective solution with minimal disruption to ongoing activites in the factory.
A pdf version of this in-situ bioremediation case study is available here.