Soil and Groundwater Remediations

Remediation of a gasworks at High Wycombe (UK)

This project comprised the remediation of the gas plant close to the centre of High Wycombe, Buckinghamshire (UK). Using its mobile soil washing system, DEC acted as a specialist subcontractor.$

The remediation was required to eliminate the soil contamination that posed a threat to the groundwater and more specifically the nearby river Wye. In addition, thanks to remediation, the site could be redeveloped into a residential zone.

DEC was responsible for the treatment of 6,100 m³ of contaminated soil, the majority of which was hazardous. The contamination consisted of tar and other hydrocarbons, particularly PAH's, phenols, ammoniac nitrogen, mineral oil and BTEX.

Given the rough nature of the soil and the type of contamination, soil washing was a suitable remediation method. DEC used one of the in-house designed and built mobile soil washing systems to wash the contaminated soil physically/chemically. The resulting sludge cakes were brought to a landfill and the clean sand and gravel fraction was reused on site.

The system achieved an average production speed of 30 tonnes an hour, depending on the type of material and the quality. The fine fraction (< 63 μm) comprised a maximum 39% of the total fraction, with an average of 24%. This means that an average reuse percentage of 76% was achieved in this project.