Bayne Stevenson Associates were appointed to undertake detailed site investigations and risk assessments of a proposed large residential development on a brownfield site in Kinghorn Fife.  Previous site uses included a candle works, leather works and tannery.  Historical studies had identified contamination concerns associated with hydrocarbons from historical fuel storage and chlorinated solvents from degreasing activities.

 

The first task completed was a detailed assessment of a significant volume of existing site data to allow focused site investigations to be completed.  The benefit to this was that the site investigations were then as efficient/cost effective as possible.

 

The results of the site investigations were subject to detailed risk assessments to ensure they met the requirements of current guidance and approvals from the planning authority.  The risk assessments identified possible risks to the development from soil contamination and soil gases/vapours due to historical spillages of chlorinated solvents.  Several potential remediation options were considered including excavation/off site removal which would have been cost prohibitive to the project as arrisings would have classed as hazardous waste.  Engineering solutions were therefore explored recommended including robustly validated gas protection measures to proposed houses, and environmental capping in landscaped/garden areas to prevent future residents coming into contact with the underlying contaminated soils.  In this scenario the requirement to dispose of hazardous waste materials to landfill was vastly reduced. 

 

The assessments also confirmed that half of the site was undeveloped/greenfield and therfore site won soils from these areas in the overall earthworks balance could be reused under appropriate materials management strategies as environmental capping elsewhere on the site, where a contamination risk was identified.

 

A risk to groundwater was also identified at the site, and a treatment strategy for groundwater contamination was developed with a specialist remediation contractor.  This involved in-situ treatment by injection of treatment chemicals over a period of 2 months on site, with follow up validation monitoring to prove the successful treatment over an 18 month period.  Given the size of the development, the remediation strategy was written in a way that allowed these longer term remedial actions to take place concurrent to development of properties elsewhere on the park, thereby preventing delays to the commencement of the development.  The remediation validation report was approved for the site by SEPA, NHBC and Fife Council.