Hilversum: CVOC

In-situ remediation technique: Soil vapor extraction

Project name: Hilversum: CVOC Case submitted by: Groundwater Technology BV Contact: Yvo Veenis Address: PO Box12115, 3004 GC Rotterdam, The Netherlands Telephone number: +031 10 238 2850 Email-address: yve@gtbv.nl

Country: The Netherlands City/region/county: Hilversum/ Noord-Holland (future) use of location: Industry Built-up location during the active remediation phase?: Yes

In situ saneringstechniek: Soil vapor extraction

Explanation technique: Two spots of perchloroethylene (perc) contamination and to a lesser extent trichloroethylene were remediated through Soil Vapour Extraction. The contamination is situated underneath an operational factory. A total of 16 extraction wells (8 in each spot) were installed. 1,5 m length screens were used. All extraction wells were installed manually indoors. Connecting piping (one line per well) ran overhead to the equipment compound. The remedial equipment consists of a moisture knock-out, an extraction blower with 200 m3 hr-1 capacity and double activated carbon filters in series.The active remediation lasted some 18 months. This phase of the remediation focused on source zone removal. Dissolved contamination in the groundwater will be monitored to become part of a regional approach to large-scale groundwater contamination contamination. Also other remediation techniques applied?: No After care needed?: No Rationale for the chosen technique: This is a privately contracted remediation project, in which GT did the assessment, remediation plan, and applied for a subsidy. The remediation was contracted for a lump-sum fee. The rationale to use SVE was: • The source of contamination is situated underneath a factory in full production (excavation was impossible) • The contamination is in the unsaturated zone. The physical properties of the contamination are amenable to the evaporation.  

Treated contaminant(s): Chlorinated volatile organic compounds (CVOC) Contaminant phase: Soil/ pure product Size contamination: 7200 m3 Depth contamination: -

Soil type: Predominantly sand Saturated/unsaturated zone?: Unsaturated zone Permeability: > 0,1 m/day, estimated based on geological data Flow velocity or gradient groundwater: Not determined

Remediation goal: Stable end situation: Perc concentration 8 mg/kg Remediation goal achieved?: Yes Initial and final concentration and load removal: Perc: initial concentration 75 mg/kg; final concentration 0,1 mg/kg Active remediation phase: 01/11/2009 till 01/04/2011 Passive remediation phase: The passive phase has not completed yet. Expected execution period: 01 /04/2011 till 01 /08/20 (only monitoring) Total costs passive/after care phase: €25.000 excl VAT Total costs active phase: Total costs € 180.000,- excl VAT

Problem owner: Contractor: Groundwater Technology Remediation plan: Groundwater Technology Remediation research: Groundwater Technology Competent authority: Province of Noord Holland Contact information stake holders:

Lessons learned: Remarks:

Related techniques: Soil vapor extraction

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