Home Remediation Case Studies Case Study L1: ISOC at a Former Gas Works (Croydon) - Petroleum Hydrocarbons
Case Study L1: ISOC at a Former Gas Works (Croydon) - Petroleum Hydrocarbons



Client: Bowmer and Kirkland

Consulting Engineer: C L Associates

Location: South East London

Remediation Value: £270,000



Client Bowmer & Kirkland
Consulting Engineer
C L Associates
Location South East London
Value £270k


Benzene plume from former benzol plant and gasworks encountered beneath a proposed new store and migrating onto site from an off site source. In-situ bioremediation of hydrocarbon impacted soils needs to continue beneath new floor slab until remedial targets are achieved. Further contamination needs to be prevented from migrating onto site without upsetting local hydrogeology.




Store must be built on schedule hence the remedial system had to be installed as part of the construction process

Churngold Solution

Believed to be the first full scale use in the UK of direct oxygen infusion cells installed in wells beneath the building footprint via trenches during the construction process. The cells are sealed beneath the floor slab with remote control systems for self cleaning and monitoring. The oxygen infusion cells induced dissolved oxygen levels of 30-40ppm within two weeks with associated bacteria counts rising from 9,000 to 19 million in the same period thus rapidly progressing the start of the bioremediation process.

An oleophilic clay Permeable Reactive Barrier (PRB) was installed on the boundary to prevent further contamination migrating onto the site.

Technologies employed

  • In-situ oxygen delivery systems
  • Oleophilic Clay Permeable Reactive Barrier (PRB)


Oxygen infusion cell control panel





Installation of permeable reactive barrier