On Thursday 26 January 2017, the Mayor of London Sadiq Khan visited Cognition at the Meridian Water site as construction enabling works formally started on Enfield Council’s £6bn regeneration scheme. 

Cognition has been commissioned by Enfield Council to remediate the groundwater beneath the site using a very innovative technique which targets free product and ultimately reduce the potential impact on the surrounding environment. The remediation works paved the way for the first phase of 725 new homes to be built along with a railway station. Decades of industrial use, including a former gas works, has left the groundwater beneath the site contaminated with both light and dense non aqueous phase contaminants (NAPL).

Cognition deployed a NAPL fabric extraction system to draw out light and dense NAPL from the groundwater using an oleophilic/hydrophobic fabric on a continuous motorised loop. The NAPL is then desorbed from the fabric by squeeze rollers and drained into containers prior to storage and ultimately removed off site for disposal. This surprisingly simple and cost-effective technique has clear advantages over conventional remediation techniques eliminating the need to pump and treat vast quantities of groundwater.

This approach to removing NAPL has already achieved great success in dealing with contaminated sites across much the USA and other countries worldwide; Cognition is now deploying this technique in the UK.

The benefits over conventional pump and treat systems are:

Recovers light & dense non-aqueous phase liquids (LNAPL & DNAPL) from contaminated groundwater direct from wells;

Eliminates the need to pump & treat groundwater;

Removes free phase contaminants with 99% efficiency;

Significantly cheaper than conventional remediation techniques;

Delivers endpoint quicker than conventional techniques;

Unaffected by fluctuating groundwater conditions;

Small footprint allows it to be deployed on operational sites;

Quick installation and low maintenance costs;

Low power requirements and can use green energy e.g. solar;

Can be monitored and controlled remotely using telemetry;

Proven technology used worldwide;

Solution approved for use by the Environment Agency

More information can be found here NAPL fabric extraction system