Terra Systems, Inc. (TSI)

- Model SD - Slow Release Substrate



SRS™ - Slow Release Substrate 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 nutrients.  SRS™ is a vegetable oil based substrate package that is used by naturally occurring microorganisms as an energy and carbon source to reductively dechlorinate solvents.

The anaerobic bioremediation process uses either native or introduced microorganisms to degrade chlorinated solvents such as tetrachloroethene (PCE) and trichloroethene (TCE) 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 and hydrogen to support biodegradation of the chlorinated solvents.  The organic substrate can be a slow release substrate like Terra Systems’ SRS™ emulsified vegetable oil substrate.  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, perchlorate, and immobilization of certain metals (Cr, As, and some radionucleides). 


Terra Systems, Inc.’s manufacturing facility is configured to allow us to provide our customers with custom blended substrate packages without a cost premium.  The basic SRS™ package contains the following components: 

  • Promotes biodegradation of PCE and TCE to non-toxic end products
  • Small droplet size is ideal for maximum radius of influence in the formation
  • Low cost
  • In situ vs. Ex situ application minimizes site disruptions
  • Slow release formula eliminates continuous substrate additions
  • SRS™ contains only non-toxic food grade materials, which results in green, sustainable remediation
  • Can be used as a PRB to cuts off plume migration
  • Effective in source zones
  • Reduces treatment time from decades to months and years

As a result of its low viscosity, small droplet size 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 direct push delivery points and overall shorter delivery time requirements per site.
Terra Systems, Inc. has applied this technology at military bases, dry cleaners and manufacturing sites throughout the USA and in Brazil and Japan. Some of the sites where the technology has been demonstrated include the Dover Air Force Base (AFB) in Delaware, Columbus AFB in Mississippi, Camp Bullis in Texas, Altus AFB in Oklahoma, Arnold AFB in Tennessee, Edwards AFB in California, Photocircuits in NY, SABRE in England and Microtronics in New Jersey.

Terra Systems, Inc. manufactures its patented “injection ready” SRSTM emulsified vegetable oil substrate (EVO) in two versions – a small droplet size for applications (SRSTM-SD) when optimizing the radius of influence is a prime objective and a large droplet size (SRSTM-FR) for fractured rock applications where adsorption in the formation is a prime concern. Terra Systems is headquartered in Wilmington, DE. and operates its own manufacturing facility in West Chester, PA. TSI has the capability of manufacturing SRSTM-SD or SRSTM-FR emulsified vegetable oil substrate in oil percentages between 45 – 60% or we can custom blend an “injection ready” mix to your specifications.

SRSTM-SD has a mean droplet size of 0.60 microns (verified by Particle Technology Labs in Downers Grove, IL.) Droplet size is critical when optimizing the radius of influence for injection is a prime objective because it increases the transport of oil-in-water emulsions through porous media. Injection of pure vegetable oil or a large droplet size emulsion could significantly reduce the radius of influence of the substrate thereby requiring more injection points and increasing operational costs. Terra Systems SRSTM-SD has the ideal combination of a very small median droplet size and a very tight distribution around the mean. This allows injection of SRSTM-SD into formations with very little change in permeability.

SRSTM-FR is a large droplet size version of our standard product designed specifically for fractured rock applications where adsorption in the formation is a prime concern. A modified manufacturing process is used to generate larger droplet sizes. As an EVO product supplier we view environmental consulting companies as our customers, not our competitors and our goal is to make you successful with your clients. Since our focus is on our products and not billable hours, we invest heavily in R&D, which is demonstrated by our involvement in SABRE, SURF, our licensing of EZVI from NASA, and our ability to manufacture a custom EVO for your specific requirements. Since we do not sub-contract SRS™ manufacturing to others, we have the ability to setup “Just-In-Time” manufacturing and delivery of SRSTM and SRSTM-FR. We work closely with the on-site project managers to produce and deliver SRSTM based on real-time site conditions. The benefit of this is that if you run into any problems, you don’t have to worry about on-site storage of large amounts of material, especially in hot weather. Terra Systems is a customer focused company where 100% customer satisfaction is our goal.

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