GEMCO’s services included; investigation risk assessment and design of a Remediation Strategy (including validation and verification proposals) which was approved by Colchester Borough Council and the Environment Agency. The site had previously been a local borough council depot until 2008. The site was redeveloped for a residential end use including houses with private gardens and 2 (no.) 3 storey block of flats with associated infrastructure.
The development also included a new public car park. GEMCO discovered a number of contamination sources on site. These included underground fuel tanks, a weighbridge pit, inspection pit, vehicle wash down area and associated interceptor. The site is underlain by River Terrace Deposits sand and gravels overlying London Clay. GEMCO’s site investigation and risk assessments confirmed that there were high levels of TPH and VOCs. The level of contamination at the site had the potential to pose a risk to human health and the environment.
GEMCO undertook remediation works with the aim to break pollution linkages. On completion GEMCO undertook validation of the works and concluded that the site is suitable for the intended proposed residential end use.
Design of Remediation Works
Post remediation ground gas and vapour monitoring proved that the risks had been successfully mitigated. No special gas protection measures were required.