The Problem

• A century of shipbuilding and maintenance had left a legacy of ground contamination at this 9.3 hectare site.
• Contamination was found to be located in many ‘hot-spots’ distributed across the site.
• Contaminants included heavy metals, phyto-toxic metals and hydrocarbons including TPH and PAH’s.
• The total volume of soil that required remediation was approximately 5,000 m³.
• Off-site disposal proved too expensive and bioremediation would have limited impact on metal concentrations.

The Solution

• Following a cost/benefit analysis, Dr McKinney proposed that an on-site containment cell represented the most practicable option.
• Consultation was held with local regulators to agree in principle the suitability of an outline design.
• A 4 metre deep containment cell fully lined with geo-synthetic/pre-hydrated bentonite membrane was constructed. Contaminated soil was placed in the cell and compacted in layers.

The Benefits

• The client received the most economic and technically robust solution.
• Movement and off-site disposal of contaminated soil was limited.
• Works could be undertaken during the initial earthworks phase of redevelopment, meaning that the programme was unaffected.
• The containment cell area could be utilised as a car parking area within the development.