In-Situ Chemical Reduction (ISCR) for Site Remediation in a Downtown Urban Setting / Former Dry Cleaner Using Direct Injection of ZVI + Carbon (EHC®).
| Country: Netherlands
| Start Date:
Project Type: Demonstration
| Contract Number:
| Organisation Type:
Consultancy, contractor or other service provider
Contaminated land-->Remediation options-->In situ treatment technologies
Groundwater protection-->Groundwater protection overview
| Project objectives:
A thorough assessment led the former consultant to conclude that there was no cost-effective remedial solution for this site. The soil consists mainly of silt,
clay and some peat, retarding COI migration. Monitored Natural Attenuation (MNA) was deemed sufficient for this case and accepted by the regulators. A back-up
scenario was available in case of unexpected COI migration. The client, a real estate investor, prefered to terminate the need for perpetual monitoring and
was willing to invest a premium in a final remedial solution. However, active measures were required to achieve this goal. Effective in situ remediation is
not always 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 would not affect COI migration.
3. The area is densely built-up and many cables, lines, pipes, ducts and sewers are present in the subsoil. Visiting customers must not be hindered by remediation
4. The area is a popular recreational-shopping area with fashionable boutiques, cafés, bars, restaurants, and summer boating.
Remediating underneath a 16th century shop downtown urban setting. A 16th century historic women’s fashion boutique on the waterfront in a medieval town centre
in The Netherlands sits on environmentally impaired property. The impacts originate from a former dry cleaner at the premises. The Constituents of Interest
(COI)—PCE and TCE—slowly degrade to DCE, VC, and ethene. However, the premises are sold and the new investor wants to terminate ‘perpetual’ monitoring.
| Achieved Objectives:
The field contractor assessed available data and concluded that natural attenuation will not sufficiently reduce source zone COI concentrations. An alternative
remedial solution for this complex case was developed. The solution was based on combining three techniques:
1. In Situ Chemical Reduction (ISCR) was selected as the most optimal approach for the source zones, where the highest COI concentrations were found. EHC®
was injected to significantly reduce COI concentrations.
2. For the other areas, enhanced natural (anaerobic) attenuation was selected, supported by the injection of a suitable substrate, to create and maintain
a strongly anoxic environment, which facilitates the degradation of chlorinated hydrocarbons.
3. Soil stabilizing agents were selected that would greatly reduce the soil’s permeability, if necessary. The result would be that groundwater could not
migrate, eliminating relocation of COIs.
Direct injection. In the first round, Groundwater Technology BV injected a balanced mixture of substrate and zero-valent iron (EHC). Active agents are
pumped into the ground through a pressurized injector system. The high injection pressure effectively disperses the slurried mixture. The amendment used
in the first injection-event consisted of a mix of micro-scale ZVI, substrate and fertilizer to chemically convert the COI’s into harmless compounds, as well
as enhance natural attenuation. Performance monitoring has shown excellent COI reduction in a timely manner. Costs were under EUR 37.000.
| Product Descriptions:
EHC® technology describes a family of remediation products used for the in situ treatment of groundwater and saturated soil impacted by heavy metals and persistent
organic compounds such as chlorinated solvents, pesticides and energetics. The technology is a modification of our DARAMEND® technology which has been used
since 1992 to treat over 9,000,000 tons of similarly effected soil and sediment. Both EHC® and DARAMEND® are the subjects of numerous patents owned by Adventus
Intellectual Properties, Inc. (Adventus).
EHC® is a controlled-release, integrated carbon and zero valent iron (ZVI) source that yields redox potential (Eh) in the -500 to -650 mV range. This Eh is
significantly lower than that achieved when using either organic materials (lactate, molasses, and sugars) or reduced metal alone. Eh potentials in this
range facilitate the timely and effective removal of normally recalcitrant chlorinated organics (e.g., CT, PCE) and other persistent compounds (e.g., perchlorate)
without the formation of potentially problematic intermediates, such as DCE/VC from the anaerobic degradation of PCE/TCE or CF/DCM from the anaerobic degradation
| Additional Information:
| Project Resources:
| Funding Programme(s):
| Link to Organisations:
Mr Mike Mueller
Who does what?
Professor Paul Bardos
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