Self-Activating ISCO / Enhanced Bioremediation Reagent
Technology Description
Ferric Oxide Activated Persulfate is an in situ chemical oxidation (ISCO) / enhanced bioremediation reagent that uses ferric iron (Fe III) as a safe and effective means of activating persulfate (US Patent No. 9,126,245; patents pending). Ferric Oxide Activated Persulfate oxidizes a wide variety of organic compounds present in impacted soil, sediment and groundwater, including chlorinated solvents, petroleum hydrocarbons, and pesticides.
Ferric Oxide Activated Persulfate is the only ISCO technology designed to actively manage rebound. The advanced activation catalyst is further unique considering its ability to enhance bioremediation processes. This combined remedy provides supplemental treatment mechanisms thereby allowing for more cost-efficient dosing of the product.
Ferric Oxide Activated Persulfate was developed by experienced practitioners who understand real-world field applications. Moreover, due to its safe and non-extreme activation chemistry, Ferric Oxide Activated Persulfate will not generate excessive heat / off-gases, nor will it mobilize heavy metals or lead to the generation of secondary impact issues.
Traditional Activation Chemistries
Heat Activation
Difficult to implement and incurs high implementation costs while not addressing the hydrogen sulfide issue.
Hydrogen Peroxide Activation
Does not address the hydrogen sulfide generation problem while having limited efficacy on many targeted compounds.
Divalent Metal Activation
Consumes the oxidant (persulfate) in a conversion of the ferrous iron to ferric iron, and the presence of the chelant inhibits biological utilization.
Caustic Activation
Presents inherit health and safety issues while creating an unsuitably high pH environment for biological attenuation.
Mode of Action
Under this approach, persulfate is activated by Fe III (pre-mixed formulation) which requires a lower activation energy than alternative mechanisms while not consuming the persulfate oxidant. The mechanism is believed to elevate the oxidation state of the iron transiently to a supercharged iron ion which in itself may act as an oxidant.
As this supercharged iron cation is consumed, the resulting ferric species can act as a terminal electron acceptor for biological attenuation. The generated sulfate ion from the decomposition of the persulfate provides a terminal electron acceptor for sulfate reducers.
S₂O₈⁻² + Fe⁺³ → Fe(+4 to +6) + SO₄²⁻ + SO₄²⁻•
Secondary Attenuation Process (Biologically Mediated)
1) Sulfate Residual
After dissolved oxygen has been depleted in the treatment area, sulfate (a by-product of the persulfate oxidation) may be used as an electron acceptor for anaerobic biodegradation by indigenous microbes. Stoichiometrically, each 1.0 mg/L of sulfate consumed by microbes results in the destruction of approximately 0.21 mg/L of BTEX compounds.
2) Ferric Iron
Ferric iron is also used as an electron acceptor during anaerobic biodegradation of many contaminants. During this process, ferric iron is reduced to ferrous iron, which is soluble in water. Stoichiometrically, the degradation of 1 mg/L of BTEX results in the average consumption of approximately 22 mg/L of ferric iron.
3) Pyrite Formation
Ferrous iron and residual sulfate promote the formation of pyrite as a remedial byproduct. Pyrite possesses a high number of reactive sites that are directly proportional to both its reductive capacity and the rate of decay for the target organics.
Primary Features
Effective
Promotes multiple free radical based in situ oxidation of a wide-range of organic contaminants with unique microbiological components.
Efficient
Significantly lower costs as a result of sub-stoichiometric dosing requirements.
Safe
Fewer health and safety concerns compared with traditional activation methods. No additional hazardous chemicals required.
Ease of Use
Single component product with integrated activator results in simplified logistics and application.
Improved Performance
Combined remedy prevents "rebound" which is often seen in other oxidation processes.
Patented Technology
US Patent No. 9,126,245 with international filings in EU, Australia, Brazil, Canada, China, Colombia, Japan and Mexico.
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