Ex-situ soil bioremediation and groundwater treatment on a former gasworks site in North Yorkshire
Client: Housing developer
Location: North Yorkshire
Contract Period: 26 weeks
This former gasworks site was acquired by a local housing developer with the aim of redeveloping the site for residential use. However, the site was heavily contaminated with oils, polyaromatic hydrocarbons, benzene, phenols and cyanide. Telluric Land Remediation was selected based on past experience as a soil bioremediation contractor and groundwater treatment specialist.
Contaminated soils, extending to depths of up to 4m, were excavated and treated on site by ex-situ bioremediation. Screened soils were formed into shallow treatment beds which were regularly rotovated, monitored and sampled. Nutrient amendments were added as necessary to optimise the rate of soil remediation. The treatment beds were covered with a waterproof membrane to minimise odour emissions and to protect from adverse weather.
A former gasholder base was uncovered and the contents, including contaminated liquids, were removed and treated on-site. A mobile groundwater treatment system was established on site for the treatment of pumped liquids, including contaminated groundwater. The system included stages for settlement, free product separation, filtration and polishing by granular activated carbon. Treated effluent was discharged to foul sewer under a temporary trade effluent discharge consent.
Treated soils were used to backfill the excavations and the site was released for residential redevelopment after a contract period of 26 weeks.
- Deployment of Environmental Permit EAWML30375
- Options appraisal and design of remediation scheme
- Excavation of contaminated materials including gasholder base
- Establishment of soil treatment beds
- Optimisation of bioremediation process
- Re-instate excavations with treated soil
- Installation and operation of groundwater treatment system
- Environmental compliance monitoring, sampling and analysis
This formerly highly contaminated site was remediated over a contract period of 26 weeks to allow cost effective residential redevelopment.
A pdf version of this gasworks remediation case study is available here.