This project was aimed at proving the viability for the use of ozone as a remediation technology for a contaminated site located on the West Coast of Scotland. While there are plenty of documented laboratory based studies on the use of ozone for the treatment of contaminated land, there are few real world examples documented from the UK and even less looking at the particular environmental factors encountered on the West Coast of Scotland.
The site used for this study was a coastal site, the soil predominately clay based although towards the coastal edge it is infilled. Previously the site was used as an oil refinery but has now been identified for redevelopment for housing, offices and parkland. Previous usage has left the site heavily contaminated with a range of Polyaromatic Hydrocarbons (PAH), Alkenes and heavy metals, all of which have the potential to cause serious health issues if left untreated when the site is redeveloped, some of the contaminants have been linked to developmental issues in children, as well as a range of potential carcinogenic compounds.
The study treated samples from the site with Ozone over a range of times and then measured the concentration of selected marker Polyaromatic hydrocarbons to identify the impact of the ozone on these to confirm that the Ozone had the ability to breakdown the PAH's. Over time it was shown that all of these compounds showed a reduction in concentration with ozone treatment, although the degree of degradation varied between the different marker compounds.
The Ozone had no direct impact on the levels of the heavy metals, but has the potential to oxidise to less toxic oxidation states. An unexpected finding identified by the study was the impact the ozone had on the physical nature of the predominantly clay based soil. The ozone has had the affect of driving the water content from the clay as well as reducing the hydrocarbon content and in the samples a 12% reduction of soil volume was seen in a 6 hour application. The engineering implications of this for the redevelopment of a treated clay site being the need for additional top soil as well as a re-evaluation of the geophysical properties of the treated material.
Andrew Robson is a MRes student studying at the David Livingstone Centre for Sustainability, at the University of Strathclyde, and is sponsored by Parsons Brinckerhoff under a industry sponsorship scheme .
The Study is a joint project with industry involving two partners, Parsons Brinckerhoff, who as well as sponsoring the Masters course also offer industrial knowledge and advice to the project and ERS Land Regeneration who have allowed access to the site and to their laboratory facilities and have helped out with some of the more practical challenges.
Andrew Robson1, Christine Switzer1, Jamie Robinson2 , Thomas Asprey3 ,Helen Keenan1
1DLCS, Department of Civil Engineering, University of Strathclyde
2Parsons Brinckerhoff, Queen Victoria House, Bristol BS6 6US
3 ERS Land Regeneration Westerhill Road , Bishopbriggs, Glasgow. G64 2QH