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Kodak, Harrow
The Challenge:
Cognition was appointed to carry out the remediation works at the former Kodak Factory in Harrow. The site is to be redeveloped by Barratt Homes with the construction of a number of residential blocks and associated landscaping and roads.
The site presented several remediation challenges given the extensive service infrastructures installed over the history of the site including a silver recovery drainage system and numerous fuel storage tanks. As a result the site was left contaminated with PAH, TPH, VOC and heavy metals. Moreover, the site ground conditions and raft foundation design presented a geotechnical challenge for the intended reuse of site won materials.
Through these works and detailed assessment Cognition has enabled the client to overcome the challenging ground conditions and provide a structurally robust subgrade for the raft foundation alternative to traditional and costly piled foundations.
The Approach
Cognition was appointed to carry out the works prior and develop a strategy for approval by the regulators. The key elements of these works included;
- Breakout and excavation and removal of underground obstructions and old infrastructure including underground storage tanks;
- Process arisings to remove oversize materials and waste items such as wood and metals;
- Pump and treat groundwater to remove NAPL and facilitate excavation;
- Bioremediation of 10,000m3 of hydrocarbon contaminated soil to enable its re-use;
- Soil stabilisation and encapsulation to reduce leachability of soil contaminants such as PAHs and heavy metals;
- Soil stabilisation to form piling mats and sub-base of new roads and hard-standings;
The Outcome
Cognition worked with the demolition contactor to ensure careful material management throughout the works and deliver the Materials Management Plan for the site. Cognition also worked closely with the consultant engineers to overcome challenging geotechnical testing and foundation design to meet the tight timescales for handing over plots for construction. Re-use of treated made ground on site delivered significant savings for the client in terms of reduced disposal.
