Ramboll was retained by a chemical industry client to assist with the closure, dismantling and remediation of a former dyestuff and pigment synthesis and formulation site in north-east France.
About the project
Detailed site characterisation works performed by Ramboll identified the need for remediation works. The site was found to be polluted with metals, organic solvents and other organic substances to depths of up to 11m. Visible impacts by dyestuffs were also identified at the site.
A sustainable solution
Remediation works started in 2017 and will be completed in 2019. They include excavation of source areas and treatment of soils under temporary shelters, to avoid health or odour impacts to the neighbouring properties.
The polluted soil is treated on site and reused to backfill the excavation. This technique was chosen as the most sustainable solution, maximising soil recycling (up to 95%), minimising consumption of virgin materials, limiting off-site disposal and off-site vehicle movements and reducing traffic and CO2 emissions.
In total, more than 80,000 m3 of polluted soil is being excavated, equating to 300,000 tonnes. The impacted materials are treated onsite using a closed-circuit washing process. Sludges from the soil washing water, equating to 6% of the total mass of excavated soil, are being disposed of off-site. Soil washing waters are 100% recycled with no discharge off-site.
Groundwater is being treated in both the source area, with dense non-aqueous phase liquid (DNAPL) removal using saturated soil substitution, and in the dissolved plume via biosparging, using oxygen injection.
As a result of this work, more than 80% of contaminant mass is being removed from the site.