Case submitted by: Groundwater Technology BV
Country: The Netherlands
Built-up site?: Yes
Soil type: Layered soil; clay/peat/sand
Follow-up required?: No
Treated contamination: Chlorinated volatile organic compounds (CVOC)
Medium contamination:
Soil/ pure product
Groundwater
Dimension contamination: 500 m3
Remediation goal: Stable and a situation without any requirement for monitoring
Remediation goal achieved?: Yes
Initial and final concentration or load removal:
Perchloroethene
Initial concentration 7800 ug/l final concentration: <0.1 µg/l
total amount initial: 22.5 kg total amount final: 0 kg
Trichloroethene
Initial concentration: 13.000 ug/l final concentration: <0.2 µg/l
total amount inital: 16 kg total amount final: 0 kg
Dichloroethenes
Initial concentration: 16000 ug/l final concentration: 0.37 µg/l
total amount inital: 11 kg total amount final: 0 kg
Vinyl Chloride
Initial concentration: 5600 ug/l final concentration: <0.2 µg/l
total amount initial: 2.2 kg total amount final: 0 kg
Active remediation phase: 13/09/10 till 21/09/10
Passive remediation phase:
The passive phase is finished. Execution period:13/09/2010 till 21/08/13
Added reports:
weesp flyer.pdf
weesp ontwerpbeschikking.pdf
weesp saneringsplan.pdf
weesp voortgangsrapportage nr 6.pdf
Weesp In Situ Chemical Reduction Volatile Chlorinated Hydrocarbons ***
Summary
In-situ remediation technique: (Enhanced) natural attenuation, anaerobic, In situ chemical Reduction (ISCR)
General information
Project name: Weesp In Situ Chemical Reduction Volatile Chlorinated Hydrocarbons ***
Case submitted by: Groundwater Technology BV
Contact: Eric de Zeeuw
Address:
PO Box 12115
3004 GC ROTTERDAM
The Netherlands
Telephone number: +31 65 319 9211
Email-address: eze@gtbv.nl
Location
Country: The Netherlands
City/region/county: City of Weesp, Province of Noord Holland
(future) use of location: Urban area
Built-up location during the active remediation phase?: Yes
Technique
In situ saneringstechniek: (Enhanced) natural attenuation, anaerobic, In situ chemical Reduction (ISCR)
Explanation technique:
A mix of microscopic zero-valent iron, organic substrate and water was injected in 35 injection points. Injection depth was 2.5 – 7 m below grade. The substrate is a carbon source to the indigenous bacteria. Consuming all available oxygen, deep anaerobic conditions result, leading to full sequential dechloration of the chlorinated hydrocarbons. The zero-valent ron leads to chemical dechloration, which degrades all chlorinated hydrocarbons at the same rate. Both processes actinf together lead to a quick and complete dechloration of the contaminants of concern. Residual products are harmless, such as ethane, ethane, chloride (ion) and (dissolved) iron.
Also other remediation techniques applied?: No
After care needed?: No
Rationale for the chosen technique:
A 16th century historic women’s fashion boutique on the water front in an medieval town centre in The Netherlands sits on contaminated land. The contamination originates from a dry-cleaner at the premises. The contaminants (Perc and Tri) slowly degrade to CIS, VC and ethene. However, the premises are sold and the new investor wants to terminate ‘perpetual’ monitoring.
A thorough assessment leads the consultant to conclude that there is no cost-effective solution for this issue. The soil consists mainly of silt, clay and some peat, retarding migration to a trickle. Just monitored natural attenuation should suffice for this case. A back-up scenario is available in case of unexpected migration.
Our client, a real estate investor, prefers to terminate the need for perpetual monitoring and is willing to invest a premium in a final solution, avoiding perpetual monitoring.
However, active measures are required to achieve this goal. Active remediation is not a simple task:
1. The subsoil is very sensitive to subsidence (wet clay & peat). The premises (like all other buildings in the area) are not based on firm foundations such as pilings: subsidence is likely to damage the property.
2. Pump & treat is virtually impossible, and in view of the low permeability, probably will not affect contaminant migration.
3. The area is densely built-up, and many cables, lines, pipes, ducts and sewers are present in the subsoil. Shopping customers must not be hindered by remediation activities.
4. The area is a popular recreational-shopping area with fashionable boutiques, café’s, bars, restaurants and (in summer) boating
Contamination
Treated contaminant(s): Chlorinated volatile organic compounds (CVOC)
Contaminant phase:
Soil/ pure product
Groundwater
Size contamination: 500 m3
Depth contamination: 7 meters below ground level
Soil
Soil type: Layered soil; clay/peat/sand
Saturated/unsaturated zone?: Saturated zone
Permeability: <0,01 m/day, estimated from bore logs
Flow velocity or gradient groundwater: Not existent
Result, duration, expense
Remediation goal: Stable and a situation without any requirement for monitoring
Remediation goal achieved?: Yes
Initial and final concentration and load removal:
Perchloroethene
Initial concentration 7800 ug/l final concentration: <0.1 µg/l
total amount initial: 22.5 kg total amount final: 0 kg
Trichloroethene
Initial concentration: 13.000 ug/l final concentration: <0.2 µg/l
total amount inital: 16 kg total amount final: 0 kg
Dichloroethenes
Initial concentration: 16000 ug/l final concentration: 0.37 µg/l
total amount inital: 11 kg total amount final: 0 kg
Vinyl Chloride
Initial concentration: 5600 ug/l final concentration: <0.2 µg/l
total amount initial: 2.2 kg total amount final: 0 kg
Active remediation phase: 13/09/10 till 21/09/10
Passive remediation phase:
The passive phase is finished. Execution period:13/09/2010 till 21/08/13
Total costs passive/after care phase: € 11.000
Total costs active phase: € 35.000
Stakeholders
Problem owner: Dubbel R Projectontwikkeling BV
Contractor: Groundwater Technology BV
Remediation plan: Groundwater Technology BV
Remediation research: Groundwater Technology BV
Competent authority: Province of Noord Holland
Contact information stake holders: Groundwater Technology BV
Additional information
Lessons learned:
'Negative' CO2 footprint: that is, more CO2 is minaralized in the soil than emitted into the atmosphere
Remarks:
This remediation was implemented in a densely built area, without any nuicance to the general public or local residents
Related techniques and HIP-pilots
Related techniques: (Enhanced) natural attenuation, anaerobic, In situ chemical Reduction (ISCR)
Related HIP-pilots: HIP-pilot Assessing stable end situation CVOC 1, HIP-pilot Assessing stable end situation CVOC 2, HIP-pilot Direct push shock load protamylasse – radius of influence and effect substrate, HIP-pilot Field comparison 2 substrates for anaerobic degradation CVOC, HIP-pilot Specific monitoring biological degradation