In Situ Bio or Chemical Remediation

Bio-Remediation systems (including processes that are NOT strictly biological) are an extension of the same processes that operate in Natural Attenuation, but are enhanced, augmented, or stimulated by human intervention. The degree to which stimulation or augmentation occurs depends on numerous factors: concentration of contaminants, presence of sensitive receptors, growth pattern of the plume, unacceptable estimated time to closure using Natural Attenuation, etc.

The choice of remediation system also depends on numerous factors, mainly related to the geochemistry and lithology of the site, along with contaminant type and concentration. The data acquired in determining if natural attenuation is appropriate are exactly the data needed to decide what active bio- or chemical remediation system is to be used and how to design its implementation.

There are numerous methods used to get material into the subsurface or enhance conditions: trenching, placement in existing wells, or injection using drill or Direct Push rigs. ESN has developed numerous novel and powerful tools and procedures for injecting substances into the subsurface for promoting or enhancing remediation processes. The tools and procedures are designed to take advantage of the knowledge of lithology and site geochemistry developed prior to remediation and to place the substance exactly, three-dimensionally, where it is needed to optimize the results.

Once these decisions are finalized, ESN can install many of these systems, namely:

Petroleum Hydrocarbons
ORC® Injection (oxygen release)
Bio-Venting using air (helium tracer gas)
Fenton’s Reagent injection
Bio-Slurping
Specialty microbe slurry injection
Nutrient injection


Chlorinated Hydrocarbons
HRC® Injection (hydrogen release)
Fenton’s Reagent
Reactive Barriers (e.g., zero valence iron)
Peroxygen compounds—permanganates and straight H2O2
Sulfide injections
Vegetable oil injections
Cheese whey injections
Methane or other hydrocarbon injection


The capabilities of ESN’s Direct Push rigs include the injection of virtually any substance into the subsurface: air, water, slurries. ESN has direct experience injecting such substances into porous, permeable formations and into clays using a hydrofracturing process. ESN has equipment specifically designed or modified for direct push rigs to meet these needs, including a variety of low to high-pressure pumps and injection tooling. Among the pumps is a GS2000, which can deliver up to 4 gpm at 1800 psi. Our ability to employ augers when needed gives ESN a special capability.