Case Study: Gasworks, Chertsey
At the 2008 Brownfield Briefing Remediation Innovation Awards, Tamdown won ‘Best Use of a Single Remediation Technique’ for their treatment of a former gasworks in Surrey using Sea Power 101. Applied to vented biopiles housed in large poly tunnels, Tamdown were able to treat and re-use 3,250 tonnes of contaminated soil.
Method: Tamdown's installed long poly tunnels to establish a greenhouse effect around the biopiles, thereby helping to optimize the bioremediation process. Sea Power 101 was then applied to help emulsify the hydrocarbons present within the soil – making them easier to break down – and to stimulate the native microbial population during their digestion. Air was continually circulated through the biopile using a low vacuum extraction system, preventing the need for mechanical turning and thus retaining heat and minimizing any disturbance to the soil’s microbial populations.
Results: Prior to the bioremediation, the site’s mean average T0 concentrations were 2,410mg/kg TPH and 1,100mg/kg total PAH. Following treatment with Sea Power 101 over a period of ten weeks, these levels fell to just 394mg/kg and 218mg/kg respectively, representing a 90% reduction in overall contaminant loading. Brownfield Briefing concluded that this was an achievement unlikely to be possible in such a short timescale in the winter months by any other bioremediation method.
Cost: Eliminating the need for the transportation and disposal of 200 lorry loads of hazardous waste to landfill and the importation of the necessary backfill, Tamdown’s bioremediation and re-use of soils resulted in a saving of GBP£195,000, which equates to more than 50% of the total contract sum.