The MAJOR DIFFERENCE between Emulsified Zero-Valent Iron (eZVI) and other ZVI products is the physical structure of the eZVI product, which is a water-in-oil emulsion (see below images). This structure makes the eZVI product hydrophobic, and therefore it is fully miscible with source material in situ. The water contained in the interior of the eZVI emulsion provides the hydrogen for abiotic reductive dechlorination reactions to proceed. Without a hydrogen donor, abiotic reactions that occur on the surfaces of the ZVI particles will not proceed. If you are implementing a source area remediation and using the eZVI technology, make sure that your product supplier can document the micellular structure and hydrophobic chemistry of their EZVI product. Please note that a combination of ZVI and emulsified oil (oil in water emulsion) WILL NOT provide the benefits that our eZVI product enables. The physical structure of the eZVI emulsion is the key to sustaining dramatic source area mass flux abatement and direct abiotic destruction of source mass, while simultaneously stimulating microbiological processes to destroy dissolved phase contaminants.
Due to the unique (patented) physical structure of eZVI, the ZVI component of the emulsion is protected inside of a hydrophobic membrane (see image above), and unlike any other ZVI products, this enables the ZVI to efficiently target the destruction of chlorinated hydrocarbons (e.g., contaminants that have the appropriate hydrophobic physical chemistry to pass through the vegetable oil membrane and contact the ZVI). Another significant difference between the technologies is the fact that eZVI takes advantage of the physical chemistry of the contaminant, and sequesters it within the vegetable oil membrane surrounding each micelle (see above images). The sequestering of contaminants into the vegetable oil membrane results in significantly reduced aqueous contaminant concentrations (~ 90% decrease), and therefore decreased mass flux from the source area. Contaminants that have phase partitioned into the vegetable oil layer then begin dissolving/diffusing into the aqueous interior of the micelle where they contact the ZVI and are destroyed (completely dechlorinated to ethane). A concentration gradient is established and the contamination is continually pulled toward the interior of the micelle where it abiotically dechlorinated. While both technologies utilize the same chemistries, eZVI is engineered to directly remediate source areas by taking advantage of the physical chemistry of the contaminant(s) and optimizing the role of abiotic reactions, which DO NOT create problematic daughter intermediates.
In addition to the above abiotic reactions, the vegetable oil membrane associated with the eZVI is a fermentable carbon source and therefore acts as an electron donor for biostimulation downgradient of the eZVI injection area(s). With eZVI you get a one-two punch; (1) optimized abiotic reactions along with (2) the polishing effects of anaerobic bioremediation processes. Target the use of your ZVI. Do not be fooled into thinking that injection of ZVI and a carbon substrate (e.g., vegetable oil, lactates, fatty acids, plant fibers) is the same as using eZVI. Our eZVI is the superior choice when remediating sites with source areas/DNAPL zones (residual or pooled).
Distributor Agreement Brings Chemical Fixation / Immobilization Technology to Tersus’ Portfolio of In Situ Soil and Groundwater Remediation Technologies
Wake Forest, NC – March 2015 – Tersus Environmental, LLC, a rapidly growing developer and marketer of advanced, innovative technologies for the remediation of soil and groundwater, and Ziltek Pty Ltd, Adelaide, Australia are pleased to announce that the two firms have entered in an agreement wherein Tersus is appointed the North American exclusive distributor for the RemBind™ product. RemBind™ is a unique powdered reagent that binds and immobilizes contaminants in in soils and sediments. RemBind™ treats a broad range of organics including PFOS, PFOA, PCBs, PCPs, PAHs, TPH, various pesticides and heavy metals such as arsenic, chromium and mercury.
Gary M. Birk, PE Managing Partner with Tersus said, “We are very pleased about the opportunity to partner with Ziltek. This agreement will facilitate a sizable expansion for Tersus into the soils and sediment remediation market. The breadth of the emerging contaminants that are amenable for treatment with RemBind™ will further enhance our leadership position in the remediation market sector. RemBind™ is a quality product for immobilization of Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoic Acid (PFOA) and a great addition to Tersus’ suite of superior technologies and products.”
“Tersus has a stellar reputation and is a recognized leader in bringing new technologies and applications to the forefront in the environmental remediation community,” said Chris Lawrence, Ziltek Commercial Manager. “Our goal is to reach as many contaminated site owners as possible that will benefit from RemBind™. Our relationship with Tersus will allow us to further the realization of that goal.”
Ethoxylated Polysorbate Surfactants and Why we Do Not Use Them
Many surfactants that have US FDA Direct Food Additive status are ethoxylated. Anytime you have an ingredient on your food label that says “polysorbate”, that’s an ethoxylated surfactant. The polysorbate surfactants are made by reacting fatty acids with a sugar molecule, then adding a polyethylene oxide chain to make it more water-soluble.
As you may know, many environmental remediation injectates, such as emulsified vegetable oil and NAPL solubilization compounds, use biodegradable, non-ionic surfactants. ESTCP 2006 and AFCEE 2007 teach how to make emulsified vegetable oil (EVO) for bioremediation using polysorbate, an ethoxylated surfactant. In Appendix H.2, AFCEE 2007 discloses the formula for an EVO product and lists polysorbate as one of the ingredients.
Unfortunately, ethoxylation, the manufacturing process that creates these surfactants (e.g., polysorbates) often results in these products containing 1,4-dioxane. While the FDA has set a limit on 1,4-dioxane at 10 ppm in polysorbates, glycerides and triglycerides, this limit is well above California’s notification level of 1 µg/L for drinking water (CDPH 2011). As a result, we do not use any of these surfactants in our vegetable oil based electron donor (EDS-ER™) or our TASK™ family of surfactants for NAPL recovery.
Tersus EDS-ER does not conatin 1,4-dioxane.
01/17/2015 – 12/31/2015
various – see website link below for details
Tersus is co-hosting this national remediation lecture series on soil and groundwater remediation technologies.
Our Technology Lecture Series brings a half-day of technical presentations on soil and groundwater remediation by a number of professionals from various organizations. These educational seminars bring together scientists, engineers, regulators, site managers and other environmental professionals from government, academia, service and R&D firms to advance the state-of-the-practice.
We know that NOT all educational events are created equal. We have worked hard to recruit both unique and impressive speakers to make the most of your valuable time. At our seminars you will connect directly with industry leading practitioners as they highlight the latest ideas for contaminant source area delineation, bioremediation and sustainable remediation technologies. You won’t want to miss this seminar!
Tersus and our partners offer these seminars at No Cost to our clients and guests from within the groundwater remediation community. Each seminar includes lunch and a certificate for 4 hours of Continuing Education. Seating for these private events is limited and you must register to attend.
Current locations are listed below:
Nutrimens® Granular, Enhancing the Efficiency of Electron Donor Utilization in Bioremediation
Bacteria are very sensitive to low pH. The optimal pH for bioremediation is between 6 and 8.5. To keep your in situ bioremediation project on track, pH should be maintained within a range where bioremediation is maximized. In general, more fermentation means more volatile fatty acid (VFA) production and lower pH. A major consequence when pH falls below 6 is a dramatic decline in enhanced reductive dechlorination.
One of the unique features of Tersus’ Nutrimens® Granular product is that the product stimulates fermentation resulting in more VFA production. Yet, its impact on pH is minimal. Doto and Liu (2011) reported and increase in total VFA production with increasing amounts of Tersus’ Nutrimens® Granular, while the pH was maintained at a higher or equal level to the control. This change could be a result of more lactate-bacteria that covert lactate to propionate (Callaway and Martin, 1997.).
Since 1943, Tersus’ business partner has been leading the industry in microbial-based fermentation research and technology innovation. The relationship between feed efficiency and methane production is well established in the dairy industry. The use of high quality metabolic nutrients that contain soluble carbohydrates such as Nutrimens® Granular has been shown to alter rumen fermentation, increase efficiency and reduce methane emissions. Nutrimens® Granular may provide the same opportunity to reduce methane production on enhanced reductive dechlorination projects. In 2015 we will continue to evaluate this development and report back to you.
Tersus introduces unique surfactant technology and implementation techniques for complex site remediation.
June 16, 2014.
Surbec Environmental (www.surbec.com) and Tersus Environmental (www.tersusenv.com) announced today the signing of a Distribution Agreement between the two firms. Under the terms of the agreement, Tersus Environmental will market, promote and serve as the worldwide distributor of Surbec’s leading surfactant technology and related products. The patented anionic surfactant formulations have the unique ability to selectively desorb and liberate sorbed petroleum hydrocarbons from soil and fractured bedrock surfaces.
A key efficacy metric for surfactants is the reduction of the interfacial force, which is the force that keeps the oil trapped within pores. Most nonionic surfactants (conventional surfactants) reduce this trapping force by about an order of magnitude. TASK™ (Tersus Advanced Surface Kinetics) reduces the interfacial force by three to four orders of magnitude allowing improved mass recovery and improved treatment by other remediation techniques.
Tersus’ anionic biodegradable surfactants provide considerable advantages.
- Dramatic reduction in cost
- Minimal surfactant mass – usually 0.5 to 0.9 weight percent
- 1 to 1.4 pore volumes for up to 95% mass removal
- The recovered oil and water gravimetrically separate within 30 minutes, making the waste stream easy to handle
- Low-cost solution – less surfactant, low disposal costs.
Supported by nearly two decades of research and formulation testing at the University of Oklahoma, TASK™ can address a wide range of applications related to hydrocarbon contamination, including:
- In situ soil and groundwater remediation
- Emergency spill clean-up
- Pipeline cleaning and spill clean-up
- Tank cleaning and sludge removal
David Alden, Technical Associate with Tersus was a guest panelist on Biotechnologies at the 2014 NC Federal Advanced Technologies Review (NCFATR) held on June 4/5, 2014 in Raleigh, NC. The Federal Advanced Technologies Review focus was on the future advanced technology needs of the Department of Defense (DoD) and other federal agencies within North Carolina. United States Senator Richard Burr, the North Carolina Military Business Center (NCMBC), North Carolina Military Foundation, University of North Carolina and the Institute for Defense and Business hosted the event.