Summary

Case submitted by: Groundwater Technology BV
Country: Netherlands
Built-up site?: Yes
Soil type: Clay
Follow-up required?: No
Treated contamination: Volatile hydrocarbons, excluding benzene (TEX)
Medium contamination: Soil/ pure product and groundwater
Dimension contamination: 12000 m3
Remediation goal: Stable end situation
Remediation goal achieved?: Yes
Initial and final concentration or load removal: Xylenes: Initial concentration 5000 ug/l, final concentration < d -700 ug/l
Active remediation phase: 01-01-2003 to 01-12-2012
Passive remediation phase:
Added reports:
tiel_beschikking_gt.pdf
tiel_evaluatierapport_gt.pdf

In-situ remediation technique:

Case detailed information

General information
Project name: Tiel: TEX (xylenes) Case submitted by: Groundwater Technology BV Contact: Yvo Veenis Address: Postbus 12115, 3004 GC Rotterdam Telephone number: Email-address: YVE@gtbv.nl
Location
Country: Netherlands City/region/county: Tiel, Gelderland (future) use of location: Industry Built-up location during the active remediation phase?: Yes
Technique
In situ saneringstechniek:
Explanation technique: This remediation comprises the phased remediation of an active industrial facility in the period 2003 – 2012. The remediation design and implementation were provided by Groundwater Technology. The remediation of the last phase was undertaken on a ‘lump sum to closure” contract basis. Four phases of remediation were implemented:Explanation technique: This remediation comprises the phased remediation of an active industrial facility in the period 2003 – 2012. The remediation design and implementation were provided by Groundwater Technology. The remediation of the last phase was undertaken on a ‘lump sum to closure” contract basis. Four phases of remediation were implemented:
  1. Pilot remediation on the smallest spot to produce ‘proof of principle’ for the remediation technique (multi-phase extraction)
  2. Remediation of a shallow hotspot through excavation inside one of the buildings;
  3. Remediation of the first core zone underneath the industrial facility through multi-phase extraction;
  4. Remediation of the second core zone underneath the industrial facility through multi phase extraction;
In total, over 200 deep and shallow extraction filters were placed up to 5 m below grade. As the soil is susceptible to subsidence, deformation monitoring and groundwater level monitoring were implemented. The remediation was phased such that remedial equipment placed in one centrally placed equipment compound can service the last two remedial phases. The regulatory authorities issued a letter stating the the remediation is completeAlso other remediation techniques applied?: No After care needed?: No Rationale for the chosen technique: The remediation was phased , starting with the smallest spot to create ‘proof of principle. The subsequent phases were developed in a cyclic design mode. Phased implementation brings the advantage that each sub-phases can be closed separately. Budget management is also easier. After a successful pilot, the technology was expanded to the larger and more contaminated source area’s. The site is contaminated with predominantly xylenes in a clay layer. Most buildings have no foundations and therefore are highly susceptible to subsidence. The remedial process was managed and monitored thus facilitating adjustments of the remedial process.
Contamination
Treated contaminant(s): Volatile hydrocarbons, excluding benzene (TEX) Contaminant phase: Soil/ pure product and groundwater Size contamination: 12000 m3 Depth contamination: 5 m-mv
Soil
Soil type: Clay Saturated/unsaturated zone?: Saturated zone Permeability: <0,01 m/day, estimation based on bore logs Flow velocity or gradient groundwater: -
Result, duration, expense
Remediation goal: Stable end situation Remediation goal achieved?: Yes Initial and final concentration and load removal: Xylenes: Initial concentration 5000 ug/l, final concentration < d -700 ug/l Active remediation phase: 01-01-2003 to 01-12-2012 Passive remediation phase: - Total costs passive/after care phase: Total costs active phase: € 1.100.000 ex VAT
Stakeholders
Problem owner: Confidential Contractor: Groundwater Technology Remediation plan: Groundwater Technology Remediation research: Groundwater Technology Competent authority: Province of Noord Holland Contact information stake holders: Groundwater Technology BV
Additional information
Lessons learned: In Situ remediation of xylenes is feasible in low permeability clay. Subsidence can be prevented by careful process management. Remarks:
Related techniques and HIP-pilots
Related techniques: