A GEL THAT nourishes bacteria has been used in the bioremediation of an industrial site in Old Stratford, Warwickshire.
The site, formerly occupied by Anglian Water, is being redeveloped for housing.
Contractor Response Bioremediation used its Response Bio Gel to treat 3,900m 3of soil containing high concentrations of diesel range organics, benzene, toluene, ethylbenzene, xylene and volatile organic compounds.
Consultant Joynes Pike & Associates commissioned the work on behalf of McClean Homes. Response worked with the Environment Agency to develop a remediation strategy and a sitespecific mobile plant licence working plan.
Bio-Gel was injected into the treatment area to 3.7m depth using 19mm diameter hand-held lances on a 1.5m grid. The nontoxic organic food grade substance is used as a carrier, insulator and initial source of nourishment for the bacteria used in bioremediation of soils and water with high levels of hydrocarbon contamination.
The gel contains the optimum mix of non-pathogenic bacteria (found naturally in soils), nutrients and dissolved oxygen. This promotes colonisation of biomass and assists bioremediation. As part of the process, the Response Bio-Gel is consumed and converted into carbon dioxide and water.
Chemical analysis of soil sampled four, eight and 12 weeks after injection finished confirmed target values had been reached, with injections reducing contamination to acceptable levels 12 weeks after work was completed.
Groundwater, surface water and soil gas were monitored during bioremediation and results used as part of the validation programme submitted to the Environment Agency. House construction began immediately injection had finished.