EDS

Client: Osborne Homes Ltd

Location: Horsham, West Sussex

The Issue

A contaminated former landfill site which had previously been a sewage treatment works. The contaminants were mostly metals, refuse and sewage sludge.

The site was surrounded by housing to three sides and a river with public road and footpath to one side. There was a history of animosity from local residents resisting the development, as the site backed onto some occupant’s gardens.

The Objective

Design the treatment solution for the targeted contaminants, develop the methodology and implement at the relevant time. The works required detailed and sensitive project management to mitigate the potential impacts to the surrounding residents and receptors.

The Solution

• Implement a remediation strategy and execute all works required to discharge the relevant planning conditions and facilitate the sale of the land to Wimpey and Southern Housing Association.
• Develop and implement the environmental monitoring strategy for the site to provide reassurance to the residents and regulators that the works had no adverse impact on both the local population and the wider environment.
• Excavation and treatment using organa-clays in a cement/bentonite soil mix matrix. This was applied using a high production technique, validating the treated soils both for environmental and geotechnical targets.
• Carry out the works to mitigate the potential impact on residents by managing the site conditions, limiting the impacts of noise, dust, odours and nuisance and by building positive relationships with stakeholders, regulators and the community at large.
• Remove all sewage sludge to landfill and import clay soils to provide an impermeable cap and geotechnical solution in accordance with the developer's specification.
• The site was sold to Wimpey and Southern Housing Association for residential development.