Creosote Contamination

VertaseFLI was appointed by SKM Enviros on behalf of Hull City Council (HCC) to remediate the gardens of two residential properties which had been determined as ‘Contaminated Land’ under Part 2A of the Environmental Protection Act.  The determination was primarily based on there being a potential pollutant linkage and significant possibility of significant harm (SPOSH) to residents from direct contact with free phase creosote contamination identified within shallow soils.

Project Details

Client

Hull City Council and SKM Enviros

Location

Hull

Project Value

£120,000

Duration

6 weeks

Services Provided

Remediation of Part 2A garden, excavation and disposal of contaminated soils, import of topsoil and reinstatement of areas of soft landscaping areas, pump and treat of contaminated groundwater, public liaison

Further Information

Public liaison was a key activity due to the number of stakeholders, particularly the tenants of the properties affected, one having a family of young children, other residents in the street, the property owners, HCC and SKM Enviros. All works were scheduled to avoid school runs, and vehicle movements within the cul de sac were accompanied by a banksman.

The site works involved the installation of sumps in the front and rear gardens to depths up to 2.0mbgl, to enable the collection of ground water and free phase contamination which was pumped to a mobile water treatment unit, comprising an oil water separator and carbon filter before being discharged to foul sewer under a local discharge consent.  The pump and treat of the groundwater lasted three weeks.

Gardens were selectively excavated up to 1.4m bgl, and soils disposed of at an appropriately licensed waste treatment facility.  On completion of the excavations, a physical barrier was installed comprising chemical resistant HDPE liner, followed by a clay layer and a capillary break layer.  Gardens were then reinstated back to the original level with sub and topsoil followed by reinstatement of fences, patio and lawns. 

The gravel pipe bed was providing a preferential pathway for the movement of creosote, therefore the trench surrounding the pipe was lined and backfilled with concrete to provide a pathway break. 

A clay stank was also installed along one boundary to prevent recontamination from a neighbouring site.

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