Between 1926 and 2011, Shell operated a variety of businesses on a riverfront property in Helsinki, Finland. The facility included an aboveground oil storage/blending facility and two underground storage caverns — between 20 and 50 metres below sea-level — were over 650 metres long each and had a total volume of 280,000 m3.
The facilities were constructed in 1970s, and used for storing middle distillate products directly in the caverns without additional containment. New city planning guidelines required that the site be closed and remediated to residential standards. In 2013, we supported Shell to exit the site, and performed a variety of tasks related to environmental investigation and remediation.
Our work included developing a conceptual site model, delivering a structural geological survey and performing risk analyses of vapour migration and bedrock groundwater. Our experts monitored and sampled groundwater and surface water, conducted a remedial feasibility study, and negotiated with regulatory agencies and government entities on the client’s behalf. The successful remediation of aboveground soils – approximately 120,000 tonnes – took place between 2011 and 2013.