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Development site remediation in Staffordshire using air sparging, soil vapour extraction and in-situ chemical oxidation

Client: Commercial developer
Location: Burton upon Trent
Contract Period: 24 months

Historic use of the site had resulted in significant contamination of the groundwater with chlorinated solvents, particularly trichloroethene.  Specialist contaminated land contractorTelluric Land Remediation proposed intensive air sparging to strip the dissolved phase solvents from the groundwater, with simultaneous soil vapour extraction to remove the stripped solvent vapours from the unsaturated zone. 

The affected area was divided into four zones to allow localised treatment via an arrangement of actuated valves operating automatically with PLC control and telemetric links.  Collected vapours were captured on granular activated carbon. 

Following the air sparging and vacuum extraction phase of works, the remaining hotspots were treated by in-situ chemical oxidation.  Potassium permanganate solution was prepared on-site, and predetermined volumes were dispensed by gravity into previously installed wells. 

Throughout the treatment works, the site was regularly monitored and sampled to assess progress towards reaching the remediation targets.  Parameters monitored included soil gas concentrations, groundwater level, VOC concentrations, conductivity, oxidation-reduction potential, dissolved oxygen and pH.  Groundwater samples were recovered and sent to an accredited laboratory for VOC analysis. 

telluric bullet Our solution

  • Field pilot trial for process optimisation
  • Installation of 120 remediation wells interconnected with compressed air and vacuum pipework
  • Automated control system with PLC control and telemetric links for remote notification of system performance and faults
  • Second phase of treatment by in-situ chemical oxidation (ISCO) to address residual hotspots
  • Groundwater sampling and monitoring

The combined in-situ remediation techniques of air sparging, soil vapour extraction and chemical oxidation provided our client with a very cost effective solution. Works were completed on schedule and within budget.

A pdf version of this development site remediation case study is available here.