For every zone of your plume, we’ve got you covered!

Giving Thanks

During this month of Thanksgiving I have been reflecting on the things I am most grateful for.  Primarily among them is our talented group of associates and business partners across the globe.  I consider myself extremely blessed to be a part of Tersus since its inception.  It’s been my home away from home. 

We have a great Team that celebrates and supports each other – through the good times and bad.  I am immensely proud of our associates and their desire to further engage and to deepen our relationships so that we can all grow together.  We bring care and passion to the table every day, and even when the occasional disagreement arises, we always come back together as Family.

I am also proud to see how our associates and business partners are happy, engaged, inspired and driven to take care of the ones that make this all possible, our clients.  Without our clients, there is no Tersus.  So on behalf of the entire Tersus family, I’d like to thank our clients for offering us the opportunity to provide technology-based solutions to manage complex, challenging environmental liabilities and reduce costs for site closure.

It’s an honor to be a part of this Team and to work with our associates and business partners in serving, our clients. I wish you a Thanksgiving filled with abundance and bright moments.


Gary M. Birk, P.E.
Managing Partner, Tersus Environmental

The Use of Tersus Marketed eZVI for Soil & Groundwater Remediation Is Not ZVI Patent Infringement


Letter from ‘709 Patent Holder

Currently, there is some confusion and uncertainty about whether the use of eZVI for soil and groundwater remediation infringes on U.S. Patent 7,531,709 (“the ‘709 patent”) titled Method for Accelerated Dechlorination of Matter. While some of you may have received notices (either oral or written) alleging that any use of ZVI plus soybean oil for soil and groundwater remediation infringes the ’709 patent, we are certain that the eZVI marketed by Tersus Environmental does not infringe on the ‘709 patent.

Tersus Environmental respects the intellectual property of others and would not intentionally promote the use of any methods or techniques which infringe a valid and enforceable patent. Further, as practitioners, you must be free to choose the appropriate methods of remediation without fear of unjustified claims of infringement or litigation. 

The eZVI patent application was filed on October 2, 2001, 461 days prior to the ‘709 patent priority date. Further, National Aeronautics and Space Administration (NASA) was granted U.S Patent 6,664,298 titled Zero-Metal Emulsion for Reduction of Dehalogenation of DNAPLS on December 16, 2003, 1,974 days (5.4 years) prior to issuance of the ‘709 patent.

The simple answer is this:  The use of Tersus eZVI product does not infringe on the ‘709 patent.

*eZVI is marketed and sold under agreement with RemQuest, a division of Toxicological & Environmental Associates.  eZVI is a NASA developed and patented technology, U.S. Patent No. 6,664,298.

Electrical Resistance Heating in Deep Bedrock

Picture from a Neighboring Quarry

Picture from a Neighboring Quarry

Electrical resistance heating is an excellent way to remediate VOCs in tight matrices. TRS Group, a company Tersus represents, has completed about 15 rock projects. The case study and article in the link below provide additional information.

Typically, ERH involves heating the subsurface to convert liquid phase contaminants to a gas phase, extracting the gases from the vadose zone and treating the vapors with conventional technologies at the surface. TRS has applied ERH at sites impacted by chlorinated solvents, volatile petroleum hydrocarbons and semi-volatile hydrocarbons. ERH is fast, simple and robust.

Some important points follow:

  • Guaranteed results
  • >99% contaminant mass (VOCs) removal within 4 to 9 months
  • No rebound
  • Equally effective in the vadose and saturated zones
  • No soil desiccation – commonly used under buildings and roads
  • Low permeability strata and sedimentary rock are ideal applications

Download Case Study & Journal Article

All Zero-Valent Iron (ZVI) Remediation Products ARE NOT THE SAME

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. 

EZVI Physical Structure

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.

eZVI Miscible with DNAP

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).

Talk copy

To learn more about eZVI or arrange a One to One with your local Technical Sales Representative, contact us today.

Tersus Environmental Signs Sales and Distribution Agreement with Ziltek Pty Ltd

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.”


Technology Update: Ethoxylated Surfactants and 1,4-Dioxane Point of Interest!

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.

Lecture Series – Soil & Groundwater Remediation Technology

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:

  • Atlanta, GA – February 17th
  • Greenville, SC – February 18th
  • Charlotte, NC – February 19th
  • Santa Ana, CA – March 4th
  • Oakland, CA – March 5th
  • Portland, OR – March 31st
  • Seattle, WA – April 1st
  • St. Louis, MO – May 5th
  • Chicago, IL – May 6th
  • Minneapolis/St Paul – May 7th
  • Indianapolis, IN – June 2nd
  • Columbus, OH – June 3rd
  • Detroit, MI – June 4th
  • Tampa, FL – September 1st
  • Raleigh, NC – September 15th
  • Denver, CO – September 23rd


Optimizing Anaerobic Bioremediation

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.).

Optimizing Anaerobic Bioremediation