Anaerobic Bioremediation

Advancing the Science of Enhanced Reductive Dechlorination

Electron Donor Solution – Extended Release EDS-ER™

As delivered, the physical state of EDS-ER™ (electron donor solution – extended release) by Tersus Environmental is significantly different than standard emulsified vegetable oil (EVO) products. Whereas other EVO products are concentrated emulsions containing water, EDS-ER™ is a water-mixable oil; it contains no water. Thus, the costs for shipping EDS-ER™ are about 50% less than conventional products.

At room temperature, EDS-ER™ is a liquid material with an appearance and viscosity roughly equivalent to vegetable oil.  Unlike common EVO products, EDS-ER™ will not separate, will not freeze, and has a shelf life of 2 years without spoilage.

EDS-ER™ does NOT contain ethoxylated polysorbate surfactants.  As you may know, many environmental remediation injectates, such as emulsified vegetable oils use biodegradable non-ionic surfactants. Unfortunately, ethoxylation, the manufacturing process that creates these surfactants (e.g., polysorbates) often results in these products containing 1,4-dioxane.


EDS-ER™ is a simple, safe, low-cost solution for the bioremediation of halogenated compounds (e.g., PCE, TCE, DCE, VC, TCA, CT, etc.), perchlorate, explosives such as aromatic nitrates, energetic munitions residuals, nitrates, acids, radionuclides, select oxidized heavy metals, and other contaminants


  • 100% fermentable and contains no water
  • Because the product is completely water mixable, the number of necessary injection points for low permeability structures decreases
  • Easily mixes with water, simplifying field operations
  • Controlled release of electron donors for up to five years
  • Food-grade carbon source
  • Low total dissolved solids to comply with secondary water quality requirements for amendments with low salt content
  • Conforms to EPA’s EPP (Environmentally Preferable Purchasing) and USDA biobased criteria
  • Neutral pH when mixed with water
  • Clean, low-cost, non-disruptive application (e.g., direct-push, wells and excavations)
  • Lowers transportation costs when compared to other electron donors
  • Over two years shelf life
  • Freezing Point is -4 °F (-20 °C)

Field Application Design

EDS-ER™ applications are easily tailored to meet site-specific conditions. Typical configurations consist of grid and barrier patterns and application in excavations or trenches.  The product’s low viscosity allows subsurface distribution through direct-push injection points, hollow-stem augers or pumped through existing wells

Packaging Options

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

Chemical & Physical Properties

Parameter                                                                                                                                  Typical Value

Organic Carbon (% by wt.)                                                                                                                    100

Refined and Bleached US Soybean Oil (% by wt.)                                                                                  93

Slow Release Organics, food grade vegetable oil derived  fatty acid esters (% by wt.)                           7

Specific Gravity                                                                                                                                 0.92 to 0.93

Electron Donor Solution – High Oil Retention Formaulation EDS-HR™

EDS-HR™ is a neat-oil surfactant blend used for anaerobic bioremediation of chlorinated halogenated straight-chain and aromatic hydrocarbons such as perchloroethene (PCE) and trichloroethene (TCE) and chlorinated phenols, perchlorate explosive materials such as aromatic nitrates, residues of energetic munitions, nitrates, acids, radionuclides and metal oxides. When emulsified in the field, EDS-HR™ produces oil droplets that are larger than those in our water soluble oil EDS-ER™. EDS-HR™is ideal for coarse materials and on sites with very high groundwater velocities as the larger droplets are readily retained. EDS-HR™ should not be used in soils with low permeability such as silts and clays. We suggest EDS-ER™ for these aquifers as EDS-ER™ provides better mobility in low permeability soils. Once injected EDS-HR™ slowly ferments to hydrogen and volatile fatty acids which supports anaerobic biodegradation for as long as five years after a single injection under ideal conditions.

Chemical and Physical Properties
EDS-HR™ is a light amber, medium viscosity, blend of soy oil, surfactants and propylene glycol. These surfactants have been specially combined to be a highly water dispersible oil-in-water emulsifier.