Enhanced Anaerobic Bioremediation

Enhanced anaerobic bioremediation is the practice of adding hydrogen (an electron donor) to groundwater and/or soil to increase the number and vitality of indigenous microorganisms performing anaerobic bioremediation (reductive dechlorination) on any anaerobically degradeable compound or chlorinated contaminant. The most commonly targeted chlorinated groundwater contaminants are primarily used in industry as degreasing agents and include:

  • Perchloroethylene (PCE)
  • Trichloroethylene (TCE)
  • Dichloroethylene (DCE)
  • Vinyl Chloride (VC)

Other anaerobically degradeable compounds include: carbon tetrachloride, chloroform, methylene chloride, certain pesticides/herbicides, perchlorate, nitrate, nitroaromatic explosives (TNT, RDX), dyes and chlorofluorocarbons (CFC’s).

Reductive dechlorination is a term used to describe the widely documented, biologically mediated process by which chlorinated hydrocarbons are degraded under anoxic or aerobic conditions. During this naturally occurring process, anaerobic microbes (dehalogenators) substitute hydrogen (H) for chlorine (Cl) on chlorinated contaminant molecules, thus dechlorinating the compound.

The Reductive Dechlorination Process

Since reductive dechlorination is a natural process it typically proceeds at very slow, unstable rates. The use of an electron donor such as Hydrogen Release Compound (HRC®) or 3D Microemulsion (3DMe®), can increase the rates of reductive dechlorination up to several orders of magnitude, rapidly taking the contaminant through the step-wise enhanced reductive dechlorination (ERD) process that ultimately results in the production of non-toxic compounds such as ethene and ethane. Under the influence of controlled-release HRC or 3DMe the ERD process can be sustained for periods of up to 2-4 years depending upon subsurface conditions.

Enhanced anaerobic bioremediation is the practice of adding hydrogen (an electron donor) to groundwater and/or soil to increase the number and vitality of indigenous microorganisms performing bioremediation (reductive dechlorination). The use of Regenesis injectable compounds to facilitate this process offers the following benefits:

The use of Regenesis’ controlled –release, injectable substrates for enhanced reductive dechlorination offer the following benefits:

  • Environmentally safe and easy to handle/apply materials
  • Viscous to semi-viscous injectable materials are easily injected and pumped into the subsurface using readily available equipment.
  • Decreased time to site closure - degradation rates accelerated orders or magnitude faster than the intrinsically slow natural pace.
  • In-situ treatment (no emplaced aboveground tanks, piping, equipment, etc.) and a single product application (depending upon the material selected) can last anywhere from 18 to 60 months, maintenance free.
  • Experience and a proven track record of success (applied on over 2,500 sites worldwide).
  • Lower costs than engineered mechanical systems and greater efficiency than high volume, rapidly consumed, liquid donors.
  • No long-term operations and maintenance
  • Minimal waste generation
  • Maximized electron donor distribution and wider spacing between injection points/wells can be achieved using 3D Microemulsion over emulsified oils.
  • Easily combined with RegenOx chemical oxidation for a complete chemical oxidation to enhanced bioremediation treatment regimen.
  • Regenesis’ world-class technical support and application design assistance free-of-charge!

3-D Microemulsion (3DMe)™

3-D Microemulsion is perhaps the most advanced electron donor material ever created. Formulated in the lab at Regenesis, this material is not just a mixture of off the shelf commodity materials but is a completely new engineered molecule (patent pending).

To learn more we encourage you to watch this 6 minute movie about the design, function, attributes and advantage over emulsified oil products.

NOTE: turn up the volume on your speakers and enjoy the show! View 3-D Microemulsion Movie

3DMe is a revolutionary new product offering the most advanced hydrogen releasing technology available ...at a price point equal to that of lesser performing simple commodity products. 3DMe is a product designed specifically for the low cost in-situ treatment of chlorinated solvent based contaminants.

3DMe incorporates the proven Hydrogen Release Compound (HRC®) patented technology in addition to a entirely new and unique patented molecule (patent pending) that is specifically designed to time release a combination of highly efficient electron donors. Additionally, 3DMe was designed with a relatively high hydrophilic/lipophilic balance (HLB), allowing dilute suspensions to be well distributed across contaminant plumes without the high injection costs.

Upon application to the subsurface, 3DMe immediately begins to produce hydrogen and to distribute hydrogen generating compounds to the subsurface through a series of hydration and fermentation reactions. This process provides for an immediate as well as time-release supply of hydrogen to fuel the demands of the anaerobic reductive dechlorination process. Typical longevity for 3DMe is up to 2 years or more on a single injection and up to 4 years or more under optimal conditions.

3-D Microemulsion (3DMe)™ Application Options

As with any injectable substrate, effective subsurface distribution is key, thus 3DMe was designed to be applied in concentrated form and in high volume. Concentrated applications are similar to that of standard HRC and involve use and injection of the product straight out of the container. High volume applications are different in that the 3DMe is mixed with water on-site, then injected into the subsurface dramatically increasing the volume and distribution of the material throughout the contaminated aquifer.

Hydrogen Release Compound (HRC®)

is a product designed specifically for the in-situ treatment of chlorinated solvent based contamination or any anaerobically degradable substance. HRC is a viscous, honey-like substance that is typically pressure injected directly into contaminated soils and groundwater. Upon contact with water, HRC slowly hydrolizes and is gradually broken down via microbial action. During this initial process, lactic acid is released and utilized (fermented) by microbes, producing optimal amounts of hydrogen and anaerobic conditions. The resulting hydrogen is then used in another, well understood, microbially mediated process known as reductive dechlorination. This naturally driven process (reductive dechlorination) is the step-by-step contaminant biodegradation mechanism which converts detrimental contaminants into harmless end products like ethene and ethane. Under the influence of HRC, this process may continue at an accelerated rate for periods of up to 18 months or longer on a single injection.

Hydrogen Release Compound [eXtended release formula] (HRC-X®)

is a product designed specifically for the in-situ treatment of chlorinated solvent based contamination especially in residual source areas and where residual dense non-aqueous phase liquid (DNAPL) is present. HRC-X is a thicker, more viscous version of HRC that is also typically pressure injected into contaminated soils and groundwater. Once in-place, HRC-X has greater longevity (periods of 36 - 48 months) than standard HRC as it takes more time for microbial action to free-up the lactic acid for fermentation. Once injected into the general vicinity of the residual source area or DNAPL, HRC-X goes to work releasing lactic acid and cost-effectively producing anaerobic conditions with optimal amounts of hydrogen throughout the area. HRC-X has been shown to produce reducing conditions for periods of 3-5 years. The newly available and controlled release hydrogen supply is then distributed as diffusive and advective forces achieving penetration into the full aquifer volume. Because of its longevity, the hydrogen resulting from HRC-X drives the long-term desorption, dissolution, and degradation of bound residual DNAPL which can otherwise be difficult to remove using traditional techniques.

Hydrogen Release Compound Primer (HRC Primer®)

is a product designed specifically for the in-situ treatment of chlorinated solvent based contamination especially in residual source areas and where residual dense non-aqueous phase liquid (DNAPL) is present. HRC-X is a thicker, more viscous version of HRC that is also typically pressure injected into contaminated soils and groundwater. Once in-place, HRC-X has greater longevity (periods of 36 - 48 months) than standard HRC as it takes more time for microbial action to free-up the lactic acid for fermentation. Once injected into the general vicinity of the residual source area or DNAPL, HRC-X goes to work releasing lactic acid and cost-effectively producing anaerobic conditions with optimal amounts of hydrogen throughout the area. HRC-X has been shown to produce reducing conditions for periods of 3-5 years. The newly available and controlled release hydrogen supply is then distributed as diffusive and advective forces achieving penetration into the full aquifer volume. Because of its longevity, the hydrogen resulting from HRC-X drives the long-term desorption, dissolution, and degradation of bound residual DNAPL which can otherwise be difficult to remove using traditional techniques

HRC Primer has also been advocated in fractured bedrock settings to get greater distribution due to its thinner physical composition..