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Advanced Oxidative Remediation Technology

 

Aztech Technologies has experience utilizing in situ and ex situ oxidative processes to remediate petroleum contaminated groundwater. Aztech Technologies has designed, installed and operated remediation systems using advanced oxidative technology to treat groundwater ex situ in trailer mounted systems. Aztech has also performed in situ treatment including the injection of oxygen releasing compounds to stimulate bioremediation and the introduction of hydrogen peroxide to directly oxidize organic compounds.

 

Electrochemical Peroxidation

 

Electrochemical Peroxidation, (ECP), is a patented adaptation of Fenton Reagent chemistry. The unique process utilizes electrochemically produced ferrous ions (Fe2+) to catalyze a radical oxidation reaction that degrades aqueous phase chlorinated and non-chlorinated contaminants to water and carbon dioxide.

Revolutionary Application of an Established Chemical Reaction

 

The Fenton Reagent Reaction has been known for more than a century, Aztech Technologies has engineered a modern day application:

  • The contaminated influent is first adjusted to slightly acidic conditions, pH 3-5, with sulfuric acid to facilitate ferrous ion production.
  • Hydrogen peroxide (H2O2) is then injected into the contaminated influent prior to the reactor.
  • A low voltage direct current is applied to parallel sacrificial steel electrodes, introducing ferrous (Fe2+) ions into solution.
  • Ferrous ions instantaneously react with hydrogen peroxide to produce hydroxyl radicals (OHo).

 

Fe2+ + H2O2 → OH- + OHo + Fe3+

Relative Oxidation Power
Cl2 = 1.0

Fluorine

Hydroxyl radical (*OH)

Atomic oxygen (singlet)

Ozone

Hydrogen peroxide

Perhydroxyl radical(*OOH)

Potassium permanganate

Chlorine dioxide

 

2.23

2.06

1.78

1.50

1.31

1.25

1.24

1.15
  • Hydroxyl radicals (OHo) instantaneously and indiscriminately degrade organic contaminants radically oxidizing them to their inorganic constituents: carbon dioxide, carbon monoxide, and water.

 

Facilitated Three Phase Remediation:

 

Three-phase remediation expedites decontamination of petroleum spill sites.

 

  • The primary treatment phase occurs ex situ in the ECP reactor and facilitates the radical oxidation of organic contaminants in the groundwater recovered from the impacted aquifer. A stream of clean water carrying trace amounts of hydrogen peroxide leaves the reactor.
  • The second phase involves re-injection of ex situ treated water immediately up gradient or within the plume of contaminated groundwater. The re-injected water, oxygenated by the trace hydrogen peroxide, promotes in situ chemical oxidation.
  • The third phase establishes aerobic conditions within the plume. Excess hydrogen peroxide raises the dissolved oxygen content of the plume, allowing native microbial populations to thrive, effectively enhancing in situ bioremediation of the contaminant plume.


    • The ECP Advantage

     

    When compared to other remediation technologies, ECP presents a clear advantage:

     

    • The inefficiency of current technology is rooted in the cyclic nature of treating a primary contaminated media in a way that produces a secondary contaminated media.
    • Ground water remediation is currently dominated by air stripping and granular activated carbon (GAC), technologies that rely on transferring organic contaminants present in extracted ground water from one phase to another.
      • Air stripping transfers organic contaminates from the aqueous phase to the vapor phase via volatilization. Organic contaminants transferred to the vapor phase, via the air stripper, are captured, via adsorption, by GAC.
      • Organic contaminants are frequently transferred from the aqueous phase to the solid phase via adsorption to GAC.
      • With both treatment technologies, incineration is necessary to destroy the extracted organic compounds.
    • ECP technology destroys organic contaminants without the production of a secondary contaminated media, consumes little energy, and in practice, is more cost-effective than other competitive techniques.
      • Contaminants treated by the ECP process are not filtered or extracted; they are completely degraded to water and carbon dioxide by the process.
      • The ECP process produces no contaminated materials or hazardous bi-products.
      • The ECP process utilizes minimal energy consumption
      • Costs for transport and treatment of contaminated secondary media (e.g. GAC) are eliminated.
      • Only small quantities of inexpensive reagents are required.


    ECP, the Future of Water Remediation

     

    The ECP process destroys organic contaminants in wastewater via an advanced oxidative reaction that is cleaner, simpler, and more cost effective than other current technologies.

     

    ECP efficiently reduces hydrocarbon compounds to non-detectable levels.

     

    ECP is cost effective, treating water contaminated by hydrocarbons without producing reaction bi-products, which must be further treated or removed from the site.

    Chart 1 Depicts data from an ECP system test conducted on July 3, 2000 in Saratoga Springs New York. Samples analyzed by Northeast Analytical Laboratories using EPA method 502.2. Contaminant concentrations are in parts per billion (ppb). Total VOC excludes MTBE.

    ECP is currently being used for removal of gasoline and fuel oil contamination from groundwater at a site in Saratoga Springs, NY. The treated effluent stream from the ECP process, when analyzed per EPA Method 502.2 shows all hydrocarbons at nondetectable concentrations.

     

    ECP is effective for reduction of MTBE in ground water. MTBE is a nefarious gasoline additive required by EPA for reduction of air pollution from automobiles. It is toxic and a suspected carcinogen. MTBE’s high solubility in ground water makes it more difficult to remove than other hydrocarbon compounds.

    Chart 2 Depicts data from an ECP Pilot test conducted on 8/15/01 in Saratoga Springs New York. 500 gal of groundwater contaminated to an MTBE conc. of 2000ppb was treated at 2gal/min. resulting in an observed 100% reduction of the compound. Samples analyzed by Northeast Analytical Laboratories using EPA method 502.2. Contaminant concentrations are in parts per billion (ppb).

    ECP technology is developing at an accelerated rate. Future engineering advances and refinements to the ECP system promise greater success in efficiency, application, and cost reduction.

     

    For more data on Electrochemical Peroxidation please consult our paper"Pilot Scale Demonstration of Electrochemical Peroxidation Process at a Petroleum Spill Site".

    Advanced Oxidation Remediation Technology