Soil and groundwater contaminated by toxic substances pose a threat to human and environmental health. Management of common environmental contaminants that include chlorinated halogenated straight chain and aromatic hydrocarbons such as perchloroethene (PCE), trichloroethene (TCE) and chlorinated phenols, perchlorate, explosive materials such as aromatic nitrates and residues of energetic munitions, nitrates, acids, radionuclides and metal oxides, allows restoring aquifers and the environment to productive use.
It is well known that creating anaerobic groundwater conditions by adding organic substrate stimulates biological mechanisms to degrade the aforementioned contaminants. Once the organic material initially consumes any oxygen and other electron acceptors such as nitrates (NO3-) and sulfates (SO42-), it provides a carbon source and serves as an electron donor during reductive dechlorination of contaminants by indigenous or exogenous microorganisms. Better understanding of the processes undergoing this degradation mechanism has increasingly taken Environmental Engineers, contractors, scientists, consultants, regulatory personnel, and others charged with remediating contaminated groundwater to engineer systems that enhance these biological mechanisms. During these biostimulation practices, emulsified vegetable oils (EVO) are a commonly deployed carbon source for enhanced halorespiration, which is the use of halogenated compounds as sources of energy.
EVO selection and delivery process must, on one hand, favor a substance with appropriate characteristics for subsurface delivery which is important to maximize contaminant contact and minimize the impact on groundwater flow conditions while providing a short and long-term source of hydrogen and carbon for enhanced reductive dechlorination. On the other, sustainability and cost considerations are factors that can determine using a product such as EDS-ER™ which ships as a 100% vegetable oil base solution yet emulsifies on site simply by adding local water without additional high-energy mixing.
EDS-ER™ is a self-emulsifying organic substrate that is an isotropic mixture of vegetable oil and vegetable oil derived fatty acid esters. EDS-ER™ has the unique ability of forming a fine oil-in-water (O/W) emulsion when mixed with water. Spontaneous emulsification to produce fine O/W emulsion occurs since the entropy change favoring dispersion is larger than the energy needed to increase the surface area of dispersion. Emulsification occurs spontaneously due to the relatively low positive or negative free energy required to form the emulsion.
Secondary environmental advantages of using EDS-ER™ include reducing greenhouse gas (GHG) emissions firstly by eliminating mechanical energy inputs and reducing substrate-shipping volumes by up to 50%. Secondly, EDS-ER™ with a long shelf life allows for on-site bulk storage, which reduces the need for excess drums and totes that would require additional energy and materials for recycling or disposal at the conclusion of the project. This non-perishable characteristic of EDS-ER™ allows intermodal or consolidated shipping to reduce transportation carbon footprint. Intermodal carriers can haul one ton of bulk liquid approximately 500 miles on a gallon of fuel, reducing by one-third the GHG emissions of equivalent trucks travelling the same distance.
It is difficult to verify the presence of DNAPLs through direct observation. A common practice is to estimate the presence of DNAPLs indirectly by applying the “1 percent of solubility” rule-of-thumb (EPA, 1992). Under this approach, DNAPL is suspected to be present when the concentration of a chemical in groundwater is greater than 1 percent of its pure-phase solubility. For example, PCE is inferred to be present as a DNAPL when the concentration of PCE is greater than 2,000 micrograms per liter (μg/L) in the dissolved phase (1 percent of its pure-phase solubility of 200,000 μg/L).
Suspected DNAPL Thresholds Based on Solubility Relative to 1 Percent of Aqueous Solubility
|Chlorinated Solvent (CAS Number)||
1% of Aqueous Solubility
|Vinyl Chloride (75-01-4)||
|Carbon Tetrachloride (56-23-5)||
|Methylene Chloride (75-09-2)||
- The reference temperature is 20 oC for the properties of these compounds.
- Source for Aqueous Solubility: EPA. 2004. In Situ Thermal Treatment of Chlorinated Solvents – Fundamentals and Field Applications. EPA 542-R-04-010.
- Source for 1 Percent Rule-of-Thumb: EPA. 1992. Estimating Potential for Occurrence of DNAPL at Superfund Sites. OSWER Publication 9355.4-07FS. NTIS Order Number PB92963338CDH.
DCA - Dichloroethane
DCE - Dichloroethene
PCE - Tetrachloroethene
TCA - Trichloroethane
TCE - Trichloroethene
In Jacksonville, Florida, the 2nd Annual Bioremediation and Sustainable Environmental Technologies Symposium allowed professionals and scientists to gather and discuss the latest trends in the contaminated site remediation industry.
Listed below are a few presentations featuring Tersus’ Technologies that you might find of interest:
- Platform presentation:Managing Geochemistry and Hydrogeology While Performing Anaerobic Bioremediation¸Presented by Mark Dockum. An EDS-ER and Nutrimens case study in California. Link
- Platform presentation: Cometabolic Bioremediation of 1,4-Dioxane presented by Randy Pratt. GSI presented results on how iSOC Technology was used to deliver oxygen, propane, nitrogen and nitrous oxide gases in groundwater to treat this recalcitrant contaminant. Link
- Poster: In Situ Treatment of a Downgradient Landfill Plume Using an Aerobic Permeable Reactive Barrier, presented by David Alden. The iSOC Technology offered an efficient and safe, low impact, low cost solution. Link
- Platform presentation:Emulsified Zero-Valent Iron (EZVI): A Combination Technology for Source Zone Remediation, presented by Greg Booth, who showed case studies and a technology overview of Tersus’s source zone solution. Link
- Platform presentation:Three Phased Remedial Approach Utilizing Multiple Degradation Pathways and Reductive Amendments To Remediate 1,1,1-TCA and TCE, presented by Patrick Gratton. This was AECOM’s presentation on a brilliant approach to remediate complex site taking advantage of local geochemical conditions. Link
- Platform presentation: Evaluation of B-12 and Nutrient Addition as Part of a Maintenance Injection to an Enhanced Reductive Dechlorination (ERD) Biobarrier, presented by Mike Kovacich. Mike with Tetra Tech showed important lessons learned from a case study. Link
- Poster: Vapor Intrusion Mitigation by Sustainable Soil Vapor Extraction, featuring Tersus’ MicroBlower, presented by Gary Birk. Link
- Poster: Cost-Effective Site Remediation Strategies: A Community-Supported Sustainable Model That Works with Even a Limited Budget, presented by Jymalin Redmond. The MicroBlower perfectly complied with the objectives of this interesting project. Link
Congratulations to this year’s student paper competition winners: Carol Beaver, Beni Camacho-Perez, Dimin Fan, Jeffrey Heenan, Kamaraj Satish-Kumar and Yi Zhang.
We would like to thank the organizers for another successful event. Key figures in our industry had an opportunity to meet and share valuable information, which in turn will drive the environmental industry towards finding more efficient, and cost effective remediation goals.
We look forward to seeing you at next year’s symposium on Chlorinated and Recalcitrant Compounds in Monterey, California.
ST. PAUL, MINNESOTA and WAKE FOREST, NORTH CAROLINA — Antea®Group, a global engineering and environmental consulting firm, and Tersus Environmental announced today the signing of an Exclusive License Agreement for US Patent No. 7138060. Under the terms of the agreement, Tersus Environmental will make, market, promote and sell products for sulfate-enhanced bioremediation of contaminated groundwater. The patent includes a process for using high concentrations of sulfate to stimulate biodegradation of petroleum hydrocarbons (PHCs), other aromatic hydrocarbons and other contaminants susceptible to sulfate-reducing bacteria.
“This license agreement with Antea®Group enables us to further expand our strong foundation of intellectual property,” says Tersus’ Managing Partner, Gary Birk. Our joint resources give Tersus customers the best biotechnology-based solutions to manage complex, challenging environmental liabilities and reduce costs for site closure.”
“We are keen to work with Tersus,” says Mike Martinson, Senior Consultant, Antea®Group. “Tersus’ network of sales associates and staff around the world will help provide a much broader market coverage for our sulfate enhanced technology.”
Enhanced aerobic bioremediation technologies such as the iSOC® gas inFusion technology or the use of oxygen releasing compounds such as TersOx™ are commonly used to accelerate naturally occurring in situ bioremediation of petroleum hydrocarbons, and fuel oxygenates such as MTBE and TBA, by indigenous microorganisms in the subsurface. However, these indigenous microorganisms do not function well in the high contaminant concentrations of the source area. Moreover, the oxygen technologies have to overcome the anaerobic conditions of the source area and often the presence of iron.
Antea®Group developed and proved a sulfate-enhanced in situ remediation strategy to address the anaerobic portion of the plume. Sulfate reduction and methanogenesis appear to dominate natural degradation processes at most sites; and therefore, adding oxygen to the anaerobic portion of the plume may be disadvantageous. The sulfate-enhanced technology, now marketed by Tersus Environmental under the name Nutrisulfate™, stimulates biodegradation by providing a soluble, readily available electron acceptor solution. In the presence of elevated sulfate, anaerobic groundwater bacteria use BTEX, MTBE and other petroleum hydrocarbons for carbon and energy while mineralizing the hydrocarbons to carbon dioxide and water. Sulfate addition enhances natural conditions and reduces the carbon footprint when compared to conventional remediation. Nutrisulfate™ is a high sulfate metabolic supplement designed to enhance the kinetics and efficiency of microbial systems specifically related to bioremediation. The increase in kinetics and efficiency decreases the remediation time and reduces the amount of substrate / amendment required.
“Deploying Nutrisulfate™ in the anaerobic source zone and one of our oxygen technologies such as iSOC® gas inFusion technology in the perimeter or outskirts of the plume gives Tersus customers the best biotechnology-based solutions to manage complex, challenging environmental liabilities. The use of these two solutions in combination speeds site closure, reduces costs, and leaves the site in an aerobic state precluding the risk of liberating unwanted substances. It’s a game changer,” says Birk.
Antea®Group is an international engineering and environmental consulting firm specializing in full-service solutions in the fields of environment, infrastructure, urban planning and water. Antea®Group includes the Belgian, Colombian, French, and United States engineering and consultancy operations of Oranjewoud N.V. In the Netherlands, engineering and consultancy services are offered under the nearly 60-year-old brand, Oranjewoud. With access to more than 3,000 employees in over 100 offices around the world and experience on all continents, Antea®Group serves clients ranging from global energy companies and manufacturers to national governments and local municipalities. For more information, visit www.anteagroup.com.
Antea®Group also is a co-founder of Inogen, a global corporation providing multinational organisations with consistent, high quality and cost effective environmental, health and safety solutions to assist our multinational clients. Inogen provides global geographic coverage with 12 Inogen Associate companies located on every continent and collectively more than 4,330 staff worldwide. The Inogen service offerings are reflected with the diversity of our membership. Inogen is able to deliver a broad spectrum of environmental, health and safety related services across the world. Inogen has completed projects in more than 120 countries. www.inogenet.com
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 on the interior of the eZVI is the hydrogen donor 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.
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 in the vegetable oil membrane surrounding each micelle (see above images). The sequestering of contaminants in the oil layer results in significantly reduced aqueous contaminant concentrations, and therefore decreases 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 its abiotically dechlorinated (i.e., so no DCE, VC associated with these reactions). While both technologies utilize the same chemistries, eZVI is engineered to directly remediate source areas by 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).
The use of carbon substrates as electron donors to enhance reductive dechlorination has been commercially used to remediate chemical contaminants since at least the early1990′s. To reduce costs, many in the industry have moved toward cheaper, less refined substrates, which alone may show poor kinetics and low efficiency.
Thus, at many sites, a common technological challenge is maintaining sufficient nutrient concentrations to support biomass growth as well as contaminant and substrate metabolism. We encourage our clients to include monitoring of groundwater nutrient levels and measurement of substrate utilization rates as indicators of in situ biological activity.
Addition of nutrients can facilitate the remediation process. Relative ratios of nutrients favorable for natural degradation are in the order of 100 Carbon / 10 Nitrogen / 1 Phosphorous / 1 Potassium / 1 Sulfur. This also means that microbes rely on the C:N ratio to break down organic contaminants. A lower carbon to nitrogen ratio is one of the indications that necessary degradation times can be reduced. Nutrimens™ liquid, which has over 12% of total carbon to help reduce the amount of additional substrate required, can add more than 6.4 g/kg of TKN as well as 2.4 g/kg of Total Phosphorus.
Some practitioners add yeast extracts to promote the activity of contaminant degrading bacteria in bioremediation of halogenated hydrocarbon-impacted groundwater. However, we are not aware of evidence that supports the claim that yeast extract enhances the efficiency of electron donor utilization in bioremediation.
Our Nutrimens™ product, an all-natural fermentation product produced during the anaerobic fermentation of an unmodified strain of botanical classification Saccharomyces cerevisiae, is a better choice than yeast extract. Besides its role in increasing the rates of bioremediation, addition of Nutrimens™ increases the efficiency of electron donor utilization. Nutrimens™ provides a source of sugars, proteins, vitamins and amino acids contained in yeast cells and extracellular metabolites which will decrease the remediation time. In addition, Nutrimens™ has also been demonstrated to aid in maintaining circumneutral pH.
Many practitioners simply add Nutrimens™ to contaminated environments to improve microbial treatment of the contaminated material. Nutrimens™ works with microbes and electron donors to improve the rate of degradation of the contaminant making the remedy faster, better, and cheaper.
For more information on Nutrimens™ please contact your local Tersus Representative or call us today at 919.453.5577 x 2002
Bacteria that are active in reductive dechlorination such as Dehalococcoides (DHC) are very sensitive to low pH. The optimal pH for DHC is between 6 and 8.5. Most microbial processes associated with the addition of electron donors tend to lower pH by the production of acidic fermentation products such as carbon dioxide and volatile fatty acids. Conversely, some microbial processes such as the reduction of sulfur stimulated by addition of an electron donor can increase pH.
While EDS-ER has a neutral pH when mixed with water, EDS-ER has no buffering as its alkalinity is below 1.0 mg CaCO3/L. We often suggest the addition of Nutrimens. Field and experimental data has shown that Nutrimens helps maintain circumneutral pH.
Sites with a ground water pH below 6.0 prior to electron donor injection are likely to produce pH values well below 6.0 after the addition of any electron donor. We often suggest performing an acidity titration on groundwater and soil slurries to evaluate the amount of alkalinity needed to reach the optimal pH range of 6.5 to 8.5. SiREM can provide this service.
Our clients have used buffers such as calcium carbonate, sodium bicarbonate, etc. with EDS-ER. These buffers are readily available for purchase at chemical suppliers and can work well in some applications. However, reapplication is common, as the buffering is typically not long lasting. Other options include adding a strong base like sodium hydroxide, but there is more of a concern with overshooting the pH and there are more Health and Safety issues in the field.
Many clients are looking to Gas Infusion technology. gPRO and iSOC units can infuse ammonia (NH3) into groundwater. Treating water with ammonia is not new. The advantages of ammonia over other neutralizing agents are increasing its popularity in industries such as mining. When ammonia meets acidic groundwater, some of the ammonia will react directly with the acid, consuming acidity, raising pH and producing the ammonium ion. Ammonia will also react directly with the groundwater producing ammonium and the hydroxyl base ions (NH3 + H20 -> NH4+ + OH-). Another benefit of ammonia is that it provides a source of nitrogen, which is an essential nutrient for microorganisms.
Wake Forest, North Carolina (October 15, 2012) – Environmental announced today David Alden has joined the firm as a Technical Associate. Based in North Carolina, Alden will provide technical and sales support for Tersus Environmental’s portfolio of biotechnology-based solutions to manage complex, challenging environmental liabilities and reduce costs for site closure.
“David is an enormous asset to the Tersus team,” said Gary Birk, P.E, Managing Partner of Tersus Environmental. “His international experience and entrepreneurial spirit will bode particularly well for Tersus and the companies we represent. David will help support the Company’s continued commitment to provide outstanding customer service and assistance.”
A graduate of Universidad de las Americas-Puebla, Mexico, where he majored in Civil Engineering with a focus on waste-water treatment. Alden worked for 4 years in the upstream oilfield sector performing offshore well tests and completion design and installation in the Gulf of Mexico. He participated in the in-situ oil-shale extraction experiment in the Piceance Basin, in Northwestern Colorado where protecting groundwater was the main challenge.
Alden recently specialized in groundwater studies, completing a Masters Degree program in Joseph Fourier University, Grenoble France. During a 4-month internship period, he conducted soil and groundwater sampling, oversaw well installation and injection procedures, as well as designed hydrogeological studies and remediation plans at a major dam construction site in the Romanche Valley, France.
Alden’s command of French, Spanish and English will assist Tersus in its international expansion.
GUELPH, ONTARIO and WAKE FOREST, NORTH CAROLINA (February 23, 2012) – SiREM (www.Siremlab.com) and Tersus Environmental (www.tersusenv.com) announced today the signing of a Sales Agency Agreement between the two firms. Under the terms of the agreement, Tersus Environmental will market, promote and sell SiREM’s bioaugmentation cultures – KB-1® and KB-1® Plus – as well as Gene-Trac® molecular testing services and treatability studies.
SiREM provides tools environmental professionals need to optimize remediation of chlorinated solvents and other recalcitrant chemicals, helping clients save money, increase remediation effectiveness and provide peace of mind during field implementation.
Tersus Environmental is a developer and marketer of advanced, innovative technologies for the remediation of soil and groundwater and is the exclusive marketing channel for inVentures Technologies groundwater products – including iSOC® Gas inFusion technology and the gPRO® oxygenation systems – as well as their various remedial uses.
“We have always been impressed with SiREM’s leadership in the area of bioremediation and treatability studies,” says Gary Birk, Managing Partner, Tersus. “As an industry leader, SiREM distinguishes itself from other solutions providers with a unique range of products and testing services combined with unparalleled technical support.”
“We are keen to work with Tersus,” says Peter Dollar, Managing Director of SiREM. “Tersus’ network of sales associates and staff around the world will help provide a much broader support function to those customers using KB-1® and related services. Our joint resources give Tersus customers the best biotechnology-based solutions to manage complex, challenging environmental liabilities and reduce costs for site closure.”
Holland, Ohio, January 14, 2012 — Ohio based Cemcor Environmental Services (CES) will expand its groundwater remediation product line for enhanced bioremediation.
The expanded product line includes Tersus’ complete family of electron donors for enhanced anerobic bioremediation, peroxygens (TersOx), and the MicroBlower, a passive soil vapor extraction technology patented by the DOE’s Savannah River National Laboratory as well as iSOC, HiSOC and gPRO from inVentures which Tersus is the exclusive worldwide representative for.
CES, led by Craig Marlow, will help support Tersus Environmental’s continued commitment to providing outstanding customer service and assistance, helping to ensure superior remediation outcomes.
“We are excited to expand our product line to include the Tersus family of soil and groundwater remediation technologies into the Great Lakes Region,” Craig said. “The electorn donors, peroxygens and the vapor extraction system are a perfect addition to our existing Gas inFusion technologies, all supporting enhanced bioremediation.”
“We are looking forward to having Cemcor Environmental Services lead our customer technical support and business development in the Great Lakes Region”, said Gary Birk, Managing Partner of Tersus Environmental. “Their unique combination of knowledge, application expertise, training skills and sales experience will make CES an invaluable member of our team as we pursue our goal to provide the best biotechnology-based solutions to effectively manage complex, challenging environmental liabilities; reducing costs for site closure; and improving customer service.”
About Cemcor Environmental Services
Cemcor Environmental Services (CES) provides marketing and technical support for various groundwater remediation technologies and services for sites impacted with petroleum hydrocarbons, chlorinated solvents, oxidized heavy metals, and energetics. Mr. Marlow has over 20 years experience in remediation contracting services, equipment, products and technologies. For more information about Cemcor Environmental Services (CES) visit www.cesremediation.com.