SRS™ 60% Emulsified Vegetable Oil Substrate

SRS™ is a patented, engineered product for the reductive dechlorination of chlorinated solvents (e.g., PCE, TCE, cis-DCE, TCA, and 1,2 DCA) or any anaerobically degradable substance (perchlorate, TNT, RDX, etc.). The substrate package is a low viscosity liquid that contains a combination of slow and fast release electron donors and required vitamins & nutrients. Its viscosity is similar to that of milk which translates into a significantly larger dispersion pattern. SRS™ may be custom blended in a variety of concentrations for site specific conditions.

One injection will typically enhance biological activity for 3 to 5 years. The composition of SRS™ is as follows:

  • SRS™ Oil Content = 60%
  • SRS™ Oil Content = 45%
  • % Fatty Acids = 0%
  • % Lactic Acid = 4% Sodium Lactate Solution
  • % Food Additive/ Emulsifiers/ Preservatives = 10%
  • Specific Gravity = 0.95-0.98 g/mL
  • pH = 6-8
  • Shelf Life Unrefrigerated = 30 – 60 days

As a result of its low viscosity and longevity, SRS™ is an ideal substrate for injection using direct-push technology.  The low viscosity allows a greater volume of SRS™ to be applied in a shorter period of time and increases the substrate delivery radius per point. This results in fewer injection points and overall shorter delivery time requirements per site.  It can also be injected into the subsurface through injection wells.

SRS™ is designed to release bio-available hydrogen over a period of 3 to 5 years thus enhancing the long-term anaerobic biodegradation of the chlorinated solvents.  SRS™ optimizes the naturally occurring biodegradation system by supplying the rate limiting factor (in this case hydrogen) in the degradation of VOC’s, certain pesticides/herbicides and immobilization of certain metals (Cr and As). 

SRS™ is available in three distinct particle sizes and with a variety of vitamin supplements. Our product is available as a 60% Oil and a 40% Oil.

Key Benefits of SRS™

Degrades PCE and TCE to non-toxic end products - SRS™ provides an environmentally acceptable environment for the bacteria to rapidly and completely dechlorinate PCE and TCE to non-toxic end products such as ethene or ethane. 

Low cost - The passive nature of the SRS™ Technology eliminates the large capital and operations/maintenance costs associated with active engineered systems such as pump and treat, air sparging with vapor extraction and continuous recirculation systems.  Savings can be as high as 90% when compared to a pump and treat system on a net present cost basis.  At a number of sites, SRS™ will be less expensive than Monitored Natural Attenuation (MNA).

Slow release eliminates continuous substrate additions- Since the SRS™ material degrades over a long period of time, SRS™ significantly reduces O&M costs compared to the repeated or continuous injections required for soluble substrates such as lactate or molasses.

Non-toxic food grade materials - SRS™ is made with food grade materials that have Generally Recognized As Safe (GRAS) status.  It can be injected directly into the aquifer through push-points or fixed wells.

Cuts off plume migration - SRS™ can be applied in a barrier configuration to avoid further plume migration. 

Optimizes dechlorination activity - By maintaining a constant source of electron donors within the contaminated aquifer, SRS™ can optimize dechlorination activity.

There are two different techniques for in situ biological transformation of chlorinated contaminants: Passive Accelerated Anaerobic Bioremediation and Accelerated Anaerobic Bioremediation.  Depending on site conditions, economics, and treatment goals one or more of these techniques can be used at the site.

Natural Attenuation: Involves the use of unenhanced natural processes as part of a site remediation strategy. These processes which can transform contaminants to less harmful forms or immobilize them to reduce risks result from biological, chemical, and physical reactions that take place in the subsurface. The dominant attenuation process for chlorinated organics is biotransformation.

Passive Accelerated Anaerobic Bioremediation: Using DPT methods, pumping into existing wells or advanced injection methods a slow release substrate such as an edible oil or edible oil emulsion is injected into the formation to generate reducing conditions and provide the native micro flora with sufficient carbon to conduct reductive dechlorination. Although a number of factors impact the speed of the biological process, the technique most likely will require less than half the time required for Natural Attenuation.

Accelerated Anaerobic Bioremediation: Using a recirculating groundwater system as the transport mechanism, a quick release substrate such as sodium lactate is continuously added and moved throughout the formation. Depending on site conditions, this technique can be expected to remediate a site in a time frame of six months to 5 years.

The accelerated anaerobic bioremediation process uses either native or introduced microorganisms to degrade chlorinated solvents such as PCE to innocuous end products including ethene and ethane. An organic substrate must be added to the groundwater to generate reducing conditions and provide the necessary carbon to support biodegradation of the chlorinated solvents. The organic substrate can be soluble compounds such as benzoate, lactate, molasses, acetate, or methanol. These soluble substrates must be added periodically at either high batch dosages or continuously at low dosages to provide the necessary carbon. Groundwater recirculation is generally necessary to distribute the dissolved organics throughout the contaminated site. Another option for the substrate would be to use a relatively insoluble compound such as edible oil (i.e. soybean oil) which would be added to the groundwater periodically (probably every two to ten years) and usually does not require the groundwater recirculation system. Additional nutrients such as nitrogen, phosphorus, trace elements, and vitamins are also needed.

The approach for stimulating in situ reductive dehalogenation dramatically reduces both the initial capital and long-term O&M costs of treating chlorinated solvent impacted formations. An injection of a low solubility, slowly biodegradable food-grade edible oil (SRS™) is made through a direct push technology or temporary injection wells. Depending on site-specific conditions, a mixture of several different oils and soluble substrates may be required. The soluble substrates are used to induce rapid, initial biodegradation of the chlorinated solvents in the more bioavailable regions (sand layers). Over time, the oils slowly dissolve and are degraded providing a steady release of dissolved organic carbon to degrade any contaminants that slowly bleed out of low permeability zones.

The key to successful implementation of an in situ bioremediation project is cost-effective distribution of electron donors. Shown below is an evaluation of several commonly used substrates: molasses, corn syrup, lactate, polylactate ester, and EVOS™. Molasses, corn syrup, lactate and other soluble substrates can be dissolved in water and flushed through the treatment zone to very effectively treat the high permeability zones. However these substrates are very rapidly degraded so they must be frequently replenished. Molasses and corn syrup are available quickly and may lead to inhibitory, low pH conditions as organic acids are rapidly released. The polylactate ester has some advantages since it can last six months or more.

  1. Distance indicates expected radial distribution away from injection point
  2. Prices reflect those obtainable for bulk chemicals in 2001.  Price per pound is based upon weight of actual electron donor.  Where present, weight of water or viscosity reducing agents is factored out of cost calculation.
  3. Harkness, M. 2000. “Economic Considerations In Enhanced Anaerobic Bioremediation”  In The Second International Conference on Remediation of Chlorinated and Recalcitrant Compounds: Vol. 4.  Battelle Press, Columbus, OH.  pp. 9-14.

Packaging Options

Packaging
  • 55-gallon poly drums
  • 275-gallon IBC containers
  • 3,000 - 5,000 gallon tankers

 

 

Materials & Safety Data Sheet

Materials Safety Data Sheet can be downloaded here in PDF format:

MSDS