ADVENTUS GROUP Outlines In Situ Chemical Reduction (ISCR) Advantages
Remediation biotechnology firm explains key differences between ISCR and Conventional Emulsified Oil technologies
CHICAGO, IL (April 08, 2009) - Adventus Americas, Inc., an international remediation biotechnology firm,
recently outlined topical decision-making criteria for remediation engineers and environmental professionals.
This summary compares and contrasts our EHC® ISCR technology with carbon-only substrates consisting of
emulsified vegetable oils. While the latter can be effective, there exist a number of fundamental differences.
The Potential Significance of ISCR
Many constituents of interest (COIs) such as chlorinated hydrocarbon compounds (CHCs) can be degraded via
oxidative or reductive processes. Accordingly, various in situ chemical oxidation (ISCO) technologies
using oxidizing agents such as Fenton's chemistry, permanganate and persulfate have been developed to remediate
impacted environments. Each of these oxidants and their activators offer seemingly unique features and they
can be very effective on a varying range of CHCs.
However, an equally or perhaps more effective remedial strategy, especially for plume treatment, entails
in situ chemical reduction (ISCR) which combines carbon plus zero-valent iron. EHC is a patented
combination of controlled-release, complex carbon plus zero valent iron (ZVI) that uniquely exhibits the
recognized benefits of ISCR. Hence, EHC integrates chemical and microbiological degradation processes that
conventional enhanced bioremediation technologies do not. When specifically compared to emulsified oils,
EHC offers the following qualitative and implementation advantages:
Top Ten Reasons to Use EHC ISCR Technology vs. Emulsified Oils
1. Better Contaminant Removal in Head-to-Head Test: Several independent comparisons of
EHC and emulsified soybean oils have been conducted. The results consistently indicate that EHC provided
greater removal efficiency for all contaminants tested, including TCE and metabolites, chlorinated ethanes,
and TCFM. Several of these reports are archived online.
2. No "Remediation" via Physical Sequestration and no Rebound: EHC contains a hydrophilic
(water loving) complex carbon source that will lasts at least 5 years in most groundwater environments. Thus,
EHC will not absorb chlorinated solvents or other hydrophobic COIs, nor will it migrate vertically once emplaced
into the subsurface. Conversely, oils are inherently lypophilic and hydrophobic which will physical absorb
contaminants which can yield temporary or apparent COI removal. Moreover, emulsified oil droplets will tend
to attract one another and may float to the water table, or sink, thus moving out of the intended remediation
zone, potentially carrying COIs with them.
3. Remediation without the Accumulation of Catabolites: EHC yields rapid COI removal
without accumulation of potentially problematic catabolites. Various ISCR reactions unique to EHC promote
rapid and complete dechlorination of target compounds (see "Thermodynamics of Low Eh Reactions" for further
scientific validation click here. Emulsified oils
depend on the presence of specific microorganisms, and support degradation reactions that proceed along
conventional sequential reductive dechlorination pathways. As such, potentially problematic / "dead-end"
intermediates such as DCE and VC from PCE or TCE, and DCM from CT or CF, will often accumulate. Emulsified
oils may also reduce the bioavailability of COIs through their sorption to the oil matrix, whereas EHC does not.
4. No Mobilization of Contaminants: Optimal volume of EHC slurry is injected without
the need for extensive water flushing, which avoids potential displacement and mobilization issues. EHC
is often applied as aqueous slurry (15 to 40% solids/weight). The small amount of water used during the
injection process therefore causes little displacement of groundwater. In contrast emulsified oil injections
are performed at lower concentrations (3% to 12% oil in water) or with water chasers and can therefore cause
substantial plume displacement. The Florida Department of Environmental Protection, for example, stated its
concerns regarding contaminant migration through the injections of emulsified oils in its acceptance letter
of an emulsified oil product1.
5. Ease of Construction: EHC is available in solid and aqueous formulations and is
manufactured regionally according to site-specific needs and conditions. It has been successfully applied
to hundreds of sites with widely varying lithologies throughout the world. Given the high solids contents
of injected slurries, field times are kept to a minimum. Oils are viscous liquids delivered as concentrated
emulsions which typically require extensive dilution in the field to yield a viscosity between 1.3 and 2.1
times that of water and/or water flooding to facilitate in situ distribution. This can translate
into significantly increased project costs due to the need for extended field time.
6. No Regulatory or Health & Safety Issues: Safe handling and easy application with
no bulky or hazardous material disposal issues. No Genetically Modified Organism (GMO) issues. No surfactants.
No secondary plume issues (TOC, heavy metal mobilization, etc).
7. pH Buffering: The alkalinity generated by the ZVI component of EHC offsets acidity
generated by fermentation of the organic carbon portion. This results in a natural buffering of pH, which
prevents acidification. There is no need for additional buffering agents which represent additional cost,
field time and potential dilution / displacement affects. In contrast, fermentation of emulsified oils
frequently leads to aquifer acidification, which can slow the rate of microbial dechlorination.
8. Superior Technology for Permeable Reactive Barriers (PRBs): EHC is ideal for placement
as a PRB because it is solid, remains where placed, and will not migrate with groundwater.
9. Adaptable Formulations for Heavy Metals: EHC is uniquely effective for environments
co-impacted with organic and inorganic contaminants (e.g., As, Hg, Ni, Pb, Zn). The presence of ZVI and
other amendments unique to EHC-M™ formulations will yield rapid, irreversible, long-term immobilization
of heavy metals - while simultaneously dechlorinating organic compounds. This is not an option with emulsified
oils since they do not provide ZVI.
10. Full Patent Indemnification for You and Your Client: EHC ISCR technology is the subject
of numerous Adventus patents. Adventus will provide full indemnification, backed by insurance coverage, to protect
users and site owners from lawsuits purporting patent infringement.
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http://www.dep.state.fl.us/waste/quick_topics/publications/pss/pcp/innovative/letters/inn_094b.pdf; Florida Department of
Environmental Protection, accessed 12 April, 2006
About Adventus Group - Environmental Biotechnologies for the 21st Century
Adventus Group provides a growing portfolio of leading environmental remediation technologies, including patented offerings from Adventus Americas Inc., and EnviroMetal Technologies Inc. Our business model supports site owners, environmental engineers, consultants, regulators, and the academic community by providing unbiased design, and selection of the most cost-effective remediation strategies. Our proprietary portfolio includes:
- in situ Chemical Reduction (ISCR) technologies:
- DARAMEND® for soils, sludges and sediments;
- EHC® portfolio of injectable amendments for groundwater;
- EHC®-A liquid formulation for wells and other networks;
- EHC®-M for immobilization of soluble metal impacts;
- A-SOX™ canister delivery system;
- ZVI PRBs and related groundwater treatment innovations;
- ZVI-Clay for in situ source zone treatment;
- EHC-O® oxygen releasing compound for in situ hydrocarbon treatment;
- O-SOX™ canister delivery system;
- ISGS™ in situ geochemical stabilization of DNAPL;
- AquaBlok® for in situ sub-aqueous capping and treatment of sediments;
- AquaBlok+™ for capping and treatment of impacted sediments;
- HoleBlok+™ down-well, low-permeability sealant;
- mGCW™ microbiologically enhanced Groundwater Circulation Wells;
- Modeling Services for optimization of remedial designs and strategies.
The Adventus scientific team is a recognized practice leader, with over 500 Abstracts published within the industry. Through March 2009, we have successfully treated over 5,000,000 metric tons of soil impacted by hazardous wastes and millions of gallons of groundwater at over 1,000 sites around the globe.
The Adventus family of companies is always seeking strategic partnerships with complementary remediation biotechnologies, and qualified international licensees in numerous countries. For more information contact Michael Mueller at mike.mueller@adventusgroup.com or visit us online at www.AdventusGroup.com or www.eti.ca.
