Complex and demanding in-situ groundwater treatment and protecting municipal water supply in Ylöjärvi, Finland

Location: Ylöjärvi
Site: Former metal workshop
Remediation: Contaminated groundwater remediation and protection the water supply
Contaminants: Tetrachloroethylene (PCE)
Description: An anaerobic biological reactive barrier (ARD) was injected into contaminated groundwater zone down gradient of the PCE-source area. The barrier was enhanced by addition of zero valent iron. The remediation work included investigation, 3D modelling, simulations, remediation design, the remediation itself and a post-clean-up monitoring phase. The clean-up was a great success, with a reductions of 90 % (PCE) down gradient of the barrier and in water supply raw water.

Multi-stage, ecologically sustainable soil remediation in Kaamanen, Lapland (Finland)

Location: Kaamanen/Inari
Site: Former petrol station
Remediation: Contaminated soil clean-up using a combination of in-situ and close-to-site -methods
Contaminants: Oil hydrocarbons
Description: Clean-up of a former petrol station property contaminated with middle distillates and petrol hydrocarbons using biological in-situ and close-to-site treatment. After the in-situ phase, the part of the soil mass with concentrations exceeding the clean-up targets was transported to a nearby (close-to-site) former airport for pile treatment. Compared to conventional dig & dump, the clean up method reduced the carbon footprint of the remediation by 90 % and the need for virgin fill soil by 50 %. The total cost of the innovative remediation approach was estimated to be about half that of dig & dump.

Contaminated soil remediation of former gas and power plant in Suvilahti, Helsinki

Location: Suvilahti, Helsinki
Site: Contaminated soil under a gasholder building
Remediation: In-situ soil remediation with soil vapor extraction (SVE) and pile treatment of excavated soil
Contaminants: Volatile hydrocarbons and PAHs
Description: The first phase of the modification (to an event venue) of the Suvilahti gasholder was the clean up of the contaminated soil under the gasholder building and the removal of explosive volatile compounds. The clean-up work was carried out using a SVE and catalytic oxidation of intake air. The remediation work was particularly challenging due to the central location and the work areas classified as explosive atmospheres. After the in-situ phase, Nordic Envicon also cleaned up the excavated PAH-contaminated soil using a combination of biological treatment and SVE. This pile treatment took place in treatment facility in Nurmijärvi. The cleaned soil mass was utilized as a landfill cover.

Biological in-situ soil remediation in Estonia

Location: Tallinn and Tapa, Estonia
Site: Train depot areas in use
Remediation: Biological in-situ remediation of contaminated soil
Contaminants: Oil hydrocarbons
Description: A filter pipeline grid was installed in contaminated areas through which the remediation chemicals were injected into the soil. Injection chemicals created conditions that enhanced the degradation of petroleum hydrocarbons by aerobic bacteria. The remediation phase lasted 2 to 3 years.

Complex and demanding in-situ groundwater and soil remediation in Kouvola

Location: Kouvola
Site: Former laundry property
Remediation: In-situ remediation of contaminated groundwater and soil
Contaminants: Tetrachloroethylene (PCE)
Description: Treatment of groundwater contaminated with PCE, PCE plume control and soil remediation. The treatment method was a biological reactive barrier injected into the groundwater zone, through which the PCE in GW breaks down. The remediation included further investigations, remediation design, remediation and an after-monitoring phase. Soil clean up was carried out by soil vapor extraction and activated carbon filtration of the intake air.

Multi-stage soil remediation in Rovaniemi

Location: Vanttauskoski, Rovaniemi
Site: Former petrol station
Remediation: Soil remediation of contaminated site
Contaminants: Oil and volatile hydrocarbons
Description: Clean up of a former petrol station property contaminated with volatile hydrocarbons and middle distillates using in-situ and on-site treatment. The in-situ methods were biostimulation and soil vapor extraction (SVE). SVE was also used for on-site pile remediation. At the end of the project, about 10 % of the contaminated soil mass was transported to the disposal center.