Harwell Groundwater Remediation
Key facts
- Project: Harwell Groundwater Remediation
- Service: Environmental services
- Location: Harwell
- Duration: Ongoing
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Project background
Chemical contamination of groundwater at Harwell was first identified in the late 1980s. It was subsequently linked to the disposal of waste chemicals in unlined chalk pits, at the Western Storage Area (WSA) and the Southern Storage Area (SSA). The SSA was also formerly used by the RAF for munitions storage.
Key challenges
We had to design and implement a programme to remediate the groundwater contamination which protects human health, meets regulatory requirements and is cost-effective. Throughout the project, we would have to manage a liability extending off-site over a significant area (approximately 10 km²). Our solution would have to accommodate difficult combinations of contaminants and hydrogeological conditions.
Our approach
To manage the contamination, we installed ‘pump and treat’ hydraulic containment plants at the source areas of contamination – the WSA and the SSA. We also implemented a strategy in conjunction with the regulators to ensure that the contaminated groundwater is not consumed.
We established a major programme of site characterisation and ongoing monitoring, following discussion with the key regulators. This entailed drilling nearly 100 boreholes and testing thousands of soil and water samples.
To remove the source of the contamination, we instigated the removal of chemical wastes from the WSA and SSA. These wastes have now been disposed of in engineered and licensed off-site waste disposal facilities. Future plans will concentrate on further treatment of contamination in the chalk at the WSA. A replacement groundwater containment plant is due to be commissioned in 2007, and is designed to operate until 2025.
The results
The remediation programme is ongoing. Key achievements to date include the installation of two groundwater containment plants, one of which has now been shut down after eight years of operation. We continue to operate extensive groundwater monitoring network. Additionally, we have successfully managed stakeholder communications.
