Case Studies: No 2

Case Study: Multiple Remediation Technologies on Gas Holder Bases of a Former Gasworks

SITE AND PROJECT SUMMARY

·       A former gasworks site that was decommissioned and used as a builders merchant’s yard. The site was to be redeveloped for residential end use.

·      The site contained two below ground gasholder bases grossly contaminated with DNAPL.

·       Average DNAPL thickness of 180 cm.

·       Initial estimated volume of DNAPL present of 100,000 litres.

·       QDS Environmental Ltd was asked to remediate the two gasholder bases to achieve betterment using best available techniques.

·       50% of the installation was installed below ground to allow an early start to the remediation while the site owner still operated as a builder’s yard.  

·       Over 50 wells were installed across the two holder bases.

REMEDIATION METHOD

Multiple technologies, both new and innovative, operated simultaneously to remove the maximum volume of DNAPL and achieve targets. Technologies used were:

·       DNAPL pumping

·       Flow Path Management

·       In-situ Conductive Heating

·       Soil Vapour Extraction

·       Surfactant Flushing

·       Chemical Oxidation

 

RESULTS

·       114,000 litres of DNAPL were removed. The largest volume removed from any QDS project.

·       Remediation targets were achieved on schedule after 10 months of operation.

·       A successful project using a combination and simultaneous operation of new and innovative technologies to remove the maximum amount of DNAPL and dissolved phase compounds.