Groundwater remediation using in-situ chemical oxidation on a former petrol station
Client: Property developer
Contract period: 8 weeks
Telluric Land Remedation was appointed to clean up this former petrol station and car showroom facility with associated garage and workshop areas. Following remediation the site was to be developed to accommodate a new 80 bed residential care home.
An Environment Agency R&D20 Level 3 Groundwater Risk Assessment was undertaken to derive targets for the various petroleum hydrocarbon fractions found to be present on the site. This allowed us to develop a remediation strategy based on in-situ chemical oxidation (ISCO). ISCO was considered likely to provide the most practical and cost-effective solution to the identified hydrocarbon contamination found at the site.
Forty remediation boreholes were installed to a depth of 4.0m in the three affected areas, covering a total remediation area of approximately 640m2. Following initial base line monitoring and groundwater sampling, chemical oxidant and catalyst were gravity fed at a controlled rate to each remediation borehole to the zone of contamination.
Post-remediation sampling showed that Aromatic >C8-C10 and Aromatic >C10-C12 fractions were below the required targets in all 11 boreholes sampled. The average residual concentrations of these fractions were 638 and 134 µg/l, representing reductions of 99.4 and 98.8%, respectively.
Following submission of our technical validation report to the Local Authority, planning conditions relating to ground contamination issues were lifted allowing site re-development to proceed.
- Remediation options appraisal
- Development of appropriate remediation strategy
- Installation of treatment wells
- Chemical treatment of three petroleum hydrocarbon plumes
- Progress monitoring and reporting
- Compilation of validation report
Remediation was very quick and cost effective allowing the development to proceed without delay.
A pdf version of this petrol station remediation case study is available here.