Recent  awards 2008-09

Brownfield Briefing Remediation Innovation Awards

QDS wins Innovation Award                       

The position of QDS in pioneering and continuing to develop and apply in-situ chemical oxidation techniques in UK was reaffirmed by winning the award in the category "Best use of Chemical systems"  

Paul Ensch, Divisional Director at Osborne, sponsors of the event, presenting the award to QDS Managing Director, Simon Curwen

The winning entry illustrates not just a pioneering use of chemical oxidation techniques, but also a creative approach by QDS and the other parties involved to making treatment based remediation work on a time and space constrained site. 

The combination of a tight programme, a busy and congested construction site, the presence of a listed building and the developer’s requirement for certainty over the outcome of remediation, called for a solution that was powerful and reliable, yet could be employed with minimal disruption to other site activities. QDS employed three distinct in-situ chemical oxidation approaches, delivered through purpose designed dosing and injection systems to successfully meet these objectives. 

The principal contaminants present on the site were dissolved and adsorbed phase chlorinated solvents (PCE, TCE, DCE, VC) within the River Terrace Gravels aquifer.   

The main constraint on remediation was the 6 week window for the remediation works to take place on site.  Out of that time, the first area of the site to be remediated had to be vacated by QDS at the end of the first week of the remediation programme, in order to allow access for steel erectors.  Additional constraints arose from the need to design the remediation system without the installation of wells within the footprint of the listed mill building and finally, the developers wish to avoid building remediation infrastructure into the development works (that is they required remediation to be completed in specific areas which could then be vacated, allowing other development work to proceed). 

In-situ chemical oxidation was a treatment technique capable of achieving the required rapid completion without extensive infrastructure requirements.  With an instruction received in August 2004, the necessary licences and approvals were first obtained (the work was carried out under one of the Mobile Plant Licences held by QDS), then remediation was carried out and the site vacated by QDS by the end of October 2004.   

The remediation works at the site utilised three distinct forms of chemical oxidation technology: 

• Conventional acidified Fenton’s Reagent oxidation was used to cost effectively deliver high impact remediation in open site areas.

• A proprietary neutral catalysed form of Fenton’s Reagent was used around newly constructed concrete piles in the new development in order to allay any concerns about possible acid attack.

• The listed mill building presented a particular challenge as the remediation system in that area had to be designed so as to avoid any intrusive works within the building footprint.  It was therefore decided to inject oxidant on the upgradient side of the building and abstract water on the downgradient side to draw the injected oxidants through the saturated impacted soils beneath the building.  For this approach to be effective the oxidant had to be stable.  Sodium Permanganate (a less powerful oxidant than Fenton’s reagent, but with greater longevity in the subsurface) was employed. 

The developer’s wish to avoid extensive “fixed” remediation infrastructure precluded the use of the conventional approach of a central treatment plant compound connected to outlying injection wells.  For this project, QDS designed and engineered a compact, mobile chemical dosing system and utilised temporary injection points driven in by a mobile rig.  The compact dosing plant allowed it to be located immediately adjacent to the injection points for the day’s operations.  This in turn allowed the remediation activity, with attendant specific safety requirements, to be enclosed in a small part of the site at any time, with other activities proceeding as normal elsewhere.   

The site maximum concentrations of PCE, recorded as 36000μg/l before remediation, were reduced by 96%.  Residual concentrations of TCE, DCE and VC were all reduced to below detectable limits at the end of the 6 week remediation programme. There has been no rebound, concentrations remain below target levels and this phase of the development has been cleared by the regulators for completion and occupation. 

The client, Thomas Fish and Sons Ltd and their development partners, together with their consultant, BWB Consulting Ltd, recognised the benefits of chemical oxidation in this scenario to resolve specific site constraints.  An essential element in the success of the approach was the careful management of the remediation work in the context of the wider site programme, facilitated through exemplary support of the developer and consultant, allowing the effective implementation of an advanced and innovative remediation solution.

Tax relief available for cleaning up contaminated land

In the Budget of March 2001, the UK Government announced a significant fiscal incentive to encourage the remediation of contaminated land. Companies may be eligible for a tax credit equal to 150% of the costs incurred in cleaning up their sites. Further, the tax credit may be claimed in the financial year in which the clean up costs are incurred.

This important measure, aimed at encouraging landowners and investors to bring contaminated land back into productive use, came into effecting May 2001 and will be reviewed after 5 years. In the meantime, many companies, including those with sites that QDS is remediating, are already benefiting from a significant reduction in real clean up costs. Needless to say there is a lot of detail in the legislation, but for more information, or to discuss how QDS could help you to get back some of the money you pay us contact: simon.curwen@qdsltd.com