Q. Who is ETEC?

A. ETEC is a remediation technology vendor (manufacturer, supplier). We offer a proprietary line of biological enhancements (nutrients, secondary electron acceptors, carbon substrates, bacteria, and surfactants) specifically designed for petroleum hydrocarbon and chlorinated solvent treatment in soil and groundwater. We also offer in situ bioremediation application equipment, including our Super-Ox™ and ISD™ systems. The Super-Ox™ is an automated groundwater recirculation and oxygenation platform capable of delivering 40 ppm dissolved oxygen to the subsurface, while the ISD™ systems deliver carbon substrates and nutrients to the subsurface to support plume-wide reductive dechlorination.

Q. How long has ETEC been in business?

A. ETEC, LLC (formerly Enzyme Technologies, Inc.) has been in business since 1991. In 1999 we developed the Dissolved Oxygen In Situ Treatment (DO-IT™) process and launched the Super-Ox™ equipment line, marking our entry into the in situ market.

Q. Who are your clients?

A. Our clients are primarily environmental consultants. ETEC supplies enhancements, equipment and technical support to the consultants who perform the system design, installation, operation, and monitoring. Please see our reference list.

Q. Is bacteria addition necessary for effective bioremediation?

A. Indigenous bacteria exist at all remediation sites, and our systems and enhancements are designed to stimulate these bacteria for degradation of target contamiannts. However, addition of bacteria at the start of a project allows us to dramatically increase plate count concentrations in the subsurface, and avoid the microbial growth “lag phase” that would occur without bacteria addition. Also, on sites with MTBE as the sole contaminant, research has shown that increased biomass concentrations increase the rate of MTBE degradation, thus making the addition of our bacteria a significant advantage on MTBE-only sites.

Q. Are your nutrients critical to the overall bioremediation process?

A. Absolutely. Our CBN™ and NutriChlor™ products are the most important components to our success with in situ bioremediation of petroleum hydrocarbons and chlorinated solvents, respectively. Bacteria require specific macro- and micro-nutrients in a specific ratio in order to create additional biomass and perform their necessary cellular functions. This is the most overlooked element in aerobic and anaerobic bioremediation processes. At chlorinated solvent sites, the lack of appropriate micro-nutrients and trace metals often produces rate-limited in situ kinetic degradation rates and incompletete dechlorination.

Q. Why do you use a soluble carbon substrate for reductive dechlorination?

A. By using our soluble CarBstrate™ substrate in combination with our ISD™ groundwater recirculation systems, we can create the necessary reductive conditions on a site-wide basis that will result in complete dechlorination or reduction of the target compounds (i.e. PCE, TCE, DCE, VC, Tetrachlorethylene, chromium, etc.). This soluble substrate subsequently supports explosive growth of biomass in the pore space of the groundwater formation; as this biomass begins to “rot”, it acts as an ideal substrate to support long-term dechlorination over time.

Q. Why do you use surfactants on your projects?

A. Mass balance calculations for most sites will reveal that the bulk of the contamination exists in the adsorbed phase (i.e. adsorbed to the soil). Therefore, in order to achieve site remediation that will not result in “rebound” (which the environmental industry is so familiar with), we have to attack the adsorbed contaminants and slowly desorb and dissolve these contaminants back into the water phase, where active microbial degradation can then occur. By using very small volumes of our surfactant solution on an ongoing basis, we can perform this necessary and important desorption process throughout active remediation.

Q. Do your biological amendments work with free product (LNAPL and DNAPL)?

A. Yes, the products will work when LNAPL (gasoline, diesel, etc.) and DNAPL (PCE, TCE) exists on the site. While we strongly encourage continued LNAPL recovery efforts, our various bioenhancements will stimulate ongoing degradation of dissolved phase hydrocarbons that result from the constant dissolution occurring at the groundwater/LNAPL interface. Aggressive free product removal techniques such as Soil Flushing/Enhanced LNAPL Recovery using our concentrated PetroSolv™ biosurfactant may also be appropriate. Please refer to the DO-IT™ technology page for more information about treatment of LNAPL.

Q. What is Dissolved Oxygen In situ Treatment?

A. Dissolved Oxygen In Situ Treatment (DO-IT™) is a groundwater recirculation process that uses our Super-Ox™ oxygenation delivery platform to supply dissolved oxygen, nutrients, and secondary electron acceptors to the subsurface on a 24/7 basis, thereby stimulating rapid, consistent biological cleanup of soil and groundwater.

Q. How is the DO-IT™ process applied?

A. The DO-IT™ technology is applied by injecting and recirculating biologically-enhanced and oxygenated water into the subsurface (using our Super-Ox™ equipment). Groundwater is extracted via submersible pumps or dual-phase extraction systems, processed through the Super-Ox™ equipment, and delivered back into the subsurface via vertical wells and/or horizontal trenches. Please refer to the DO-IT™ technology discussion for further information.

Q. Does the DO-IT™ technology work with free product (LNAPL)?

A. Yes, the DO-IT™ technology can effectively treat sites with thin layers of LNAPL by stimulating constant degradation of dissolved constituents at the groundwater/LNAPL interface. If significant LNAPL exists (i.e. consistent layers greater than 2 inches, for example), we strongly encourage aggressive LNAPL recovery efforts which can be used in conjuction with the DO-IT™ technology for enhanced recovery. Please refer to our detailed DO-IT™ process description for additional information about LNAPL treatment.

Q. What are electron acceptors, and why are they important for bioremediation?

A. All biological processes require an electron donor and an electron acceptor to produce the oxidation-reduction reactions that transform the organic contaminants (i.e. petroleum hydrocarbons) to carbon dioxide and water. In aerobic bioremediation, oxygen is the required electron acceptor contaminant degradation. Anaerobic degradation utilizes a range of electron acceptors, including nitrate, iron, manganese, sulfate, and carbon dioxide.

Q. Are certain electron acceptors preferred over others?

A. Yes. Bacteria utilize electron acceptors in a predictable, reliable sequence. The generally accepted order for these electron acceptors, from most desired to least desired (left to right), is as follows:

Oxygen > Nitrate > Iron (+3) > Manganese (+4) > Sulfate > Carbon Dioxide

Q. How much electron acceptor mass is needed to remediate my site?

A. Oxidation-reduction reactions require a specific mass of electron acceptor in order to degrade a specific mass of contaminant (i.e. petroleum hydrocarbon). Specifically, oxygen:TPH is required in a 3:1 ratio, while nitrate:TPH is required in a 5:1 ratio. So a site that has 1,000 lbs. of TPH contamination will require 3,000 lbs. of dissolved oxygen, 5,000 lbs. of nitrate, or a combination of the two. ETEC utilizes these mass requirements to provide accurate remediation timeframes and required bioenhancement application rates.

Q. What is Super-Ox™?

A. Super-Ox™ is an automated biological product application and oxygen delivery system. The Super-Ox™ simplifies the process of implementing in situ bioremediation and provides for easy specification and installation by the remediation system designer.

Q. How much oxygen does Super-Ox™ equipment generate?

A. The Super-Ox™ equipment generates dissolved oxygen concentrations greater than 40 parts per million, which is more than 4 times the D.O. level achieved by air injection. In addition to the dissolved oxygen in the process stream, a large mass of undissolved gaseous oxygen is delivered to the groundwater and unsaturated zones.

Q. How does the Super-Ox™ equipment generate such high levels of dissolved oxygen?

A. The Super-Ox™ equipment uses a unique pure oxygen mixing system to efficiently dissolve oxygen into water. The mixing process is entirely mechanical; no chemical additives or ozone are used in the oxygenation process.

Q. How is it possible to achieve 40 ppm dissolved oxygen?

A. The solubility of pure oxygen in water is much higher than air because pure oxygen (95% oxygen) has a much higher partial pressure than air, which is only 21% oxygen. Learn more about this topic here.

Q. Is the 40 ppm of dissolved oxygen stable?

A. Yes. The Super-Ox™ equipment controls the mixing process, fully saturating the water with oxygen up to the maximum solubility concentration of 40 ppm. The measured half-life of the dissolved oxygen in the process water is two to three weeks.

Q. How big is the Super-Ox™ equipment?

A. The Super-Ox™ units vary in size depending on the design flowrate. Please contact us for more information.

Q. How much power does Super-Ox™ equipment require?

A. The Super-Ox™ power requirements vary by the size of the unit. Please contact us for more information.

Q. What is the ISD™ system?

A. ISD™ equipment is an automated groundwater recirculation and substrate/oxidant delivery system. The ISD™ systems overcome the subsurface delivery limitations that are inherent with slug injection applications, producing plume-wide delivery of substrates, nutrients, and/or chemical oxidants.

Q. How is the ISD™ system applied?

A. On chlorinated solvent sites, the ISD™ system is set up for continuous groundwater circulation combined with pulsed substrate injection (continuous substrate injection results in infrastructure fouling problems). The groundwater circulation is typically performed for 3-6 months, with the goal of producing biomass growth throughout the pore space of the groundwater formation. After groundwater circulation ceases, the biomass begins to “rot”, producing degradation byproducts that are ideal substrates to maintain long-term dechlorination over time.

Q. How long can the ISD™ system maintain reductive subsurface conditions?

A. Current data from numerous chlorinated solvent sites indicates that with as little as 3 months of active groundwater circulation and pulsed injection of our soluble substrate (CarBstrate™), the ISD™ process has been able to maintain reductive conditions (and active dechlorination) for 18 to 24 months.

Q. How big are the ISD™ systems ?

A. The ISD™ units vary in size depending on the design flowrate, which ranges from 10 gpm to 40 gpm.. Please contact us for more information.

Q. How much power does the ISD™ equipment require?

A. The ISD™ power requirements vary by the size of the unit. Please contact us for more information.