Cadishead - Salford

As a former Clariant Chemicals tar processing plant, comprising 18 acres, the soils and groundwater had become heavily impacted with a range of chemicals, including naphthalene and TEX (Benzene, Toluene, Ethylbenzene and Xylene) products. However, these issues did not stop Harrow from completing an unconditional purchase in a short timeframe. The site overlaid the Sherwood Sandstone, a Major Aquifer, as well as sitting alongside the Manchester Ship Canal and as such the remedial strategy required close liaison with the Environment Agency and Salford City Council.

In close proximity to occupied residential property, Harrow and its consultant partners completed the following tasks:

• Excavated 150,000 m3 of soil to depths of up to 5m.
• 90,000m3 of soil was placed into windrows for treatment.
• The site came Runner Up in the Brownfield Briefing Awards ‘Best Use of a Combination of Techniques’ category in 2008 (only beaten by the Olympic Development).
• Groundwater in some 6,000 sq mtrs of the site was treated using in-situ air-sparging and soil vapour extraction (SVE) methods in order to deal with impact to the aquifer.
• Outline planning consent was secured for 400 homes with no affordable housing and a Section 106 Agreement which recognised the technical challenges of the site.
• The treated soil material was restored and compacted in layers to allow development to take place.
• Groundwater was treated at a custom built water treatment plant on site.
• The site was sold to Redrow Homes and Taylor Wimpey for development.