E-Redox Sustainable Remediation Tool

AdvancedEnvironmentalTechnologiesLLC AET

E-RedoxInnovativeandcustomizabletechnologiesthatkickstartandenhance“bioelectrochemical”reductiveandoxidativereactionsforcost-effectiveinsituandexsitudegradationofcontaminants

E-Redox is a patented technology recently developed by Advanced Environmental Technologies, LLC (AET). Both laboratory and field applications of E-Redox have demonstrated the sustainability and cost-effectiveness of this technology in enhancing the degradation of a number of recalcitrant contaminants in groundwater, soil, and sediments. There are two major classes of E-Redox technologies provided by AET: E-Redox-In and E-Redox-Out.

E-Redox-In is generally for reductive applications (e.g., TCE dechlorination), though, there are instances when both reductive and oxidative reactions may occur. E-Redox-Out is generally for oxidative applications (e.g., petroleum hydrocarbons)

Applications

• Organic contaminants o Examples: Chlorinated solvents, PAHs,

petroleum hydrocarbons • Inorganic contaminants

o Examples: Perchlorate, nitrate, metals • Stand-alone technology for treating a variety of

contaminants in situ and ex situ applications • Integration with other remediation technologies to

achieve significant enhancement • Restoration and enhancement of permeable reactive

barriers (includes depassivation of ZVI)

Advantages

• Implementable in wide-range of matrices, including low permeable zones

• Electrochemical applications (E-Redox-In) requires very low energy input

• Bioelectrochemical applications (E-Redox-Out) requires zero energy input and generates electricity

• Effective as stand-alone treatment • Synergistic to other remediation

technologies (e.g., electron acceptor amendments, injection of carbon)

E-Redox-Out :EnhancingBio-Oxidation

The E-Redox-Out technology works as a bioelectrochemical system in an open-configuration.

• The anode (in contact with the contaminated matrix) and the established biofilm at the anode-matrix interface serve as a solid and highly conductive electron collector and interim electron acceptor for electrons released from biodegradation.

• The circuit serves as a conduit to transfer electrons to the cathode (exposed to ambient air), and electricity is generated during the electron transfer. Meanwhile, protons migrate through the matrix towards the cathode.

• The cathode (at its interface with air) serves as a perpetual electron acceptor that consumes the electrons and protons and completes the electron transport.

• The E-Redox-Out system stimulates biological oxidation by expediting electron transfer from the biodegradation process, “snorkeling” electrons to ambient O2 as the terminal electron acceptor, competing with microorganisms for extracellular electrons thus accelerating metabolic rates, and maintaining low electron density and H2 levels in the matrix to eliminate potential product feedback and inhibitory influences.

Benzene was the primary groundwater contaminant concern at existing gas stations in Denver, CO. The E-Redox-Out technology was tested using spiked samples from the site and compared to other electron accepting conditions. The highest benzene biodegradation rate of 585 µg/L/day was observed for E-Redox-Out. Two wells near one gas station were selected for installation of E-Redox-Out units, and each well had adjacent monitoring wells within 9 to 11 ft. After approximately three months, the benzene concentrations decreased by over 90% to below the groundwater standard.

CASE STUDY: Benzene-Contaminated Groundwater, Denver, Colorado

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Date& MW017pz& MW021pz&11/23/15! 0.165! 0.026!12/1/15! <0.001! 0.026!3/16/16! 0.002! 0.002!

CASE STUDY: Petroleum Hydrocarbons-Contaminated Groundwater, South Dakota

An E-Redox-Out unit was installed at a former gas station in rural area in South Dakota, where leaking underground storage tank impacted the groundwater with petroleum hydrocarbons (free product was present at approximately 3 ft thick in two monitoring wells). After less than one year since the installation of the E-Redox unit, over 60% of the GRO-TPH was degraded, while over 90% of the benzene was degraded). Voltage production was observed indicating biodegradation.

E-Redox-In :ElectricallyInducedRedox

Technology Working Principal

Water/Solute Movement Towards

Electrodes Voltage Gradient

Electrokinetic (EK) Remediation

Induces movement of contaminants, amendments, and water within a contaminated matrix; often requiring pH buffering at electrode wells and water capture/treatment.

Yes (pH buffering

and conductivity

replenishment required)

High >20V/m

Electrical Barriers

Parallel electrode plates placed close to each other to intercept the plume. Contaminant (TCE) reduction occurs as plume moves through the plates. Most activity on or near the cathodic plate.

No (pH changes

observed down-gradient)

High 100 -

300V/m

E-Redox-In

Establishes redox reactions between electrodes at the soil particle/water interface to uniformly degrade contaminants in the soil matrix. No contaminant movement. No pH buffering requirement. Appropriate for source area treatment.

No Low 1-10V/m

!

E-Redox-In technologies generate a low-voltage gradient electric field in between electrodes, uniformally inducing redox reactions within environmental matrices. The soil/sediment particles with the matrices become “micro-electrodes” within the induced electric field, triggering and sustaining numerous redox reactions. Contaminants within the matrix are susceptible to these redox reactions, and are rapidly degraded or transformed. Additionally, microbial activities within the electric field can also be by the redox reactions, which further enhances contaminant degradation/transformation. E-Redox-In is typically applicable to highly-oxidized contaminants such as chlorinated solvents (e.g., TCE), oxidized metals (e.g., Cr6+), oxyanions (e.g., nitrate), among others; however, E-Redox-In is also applicable for soils/sediments contaminated with polycyclic aromatic hydrocarbons (PAHs).

CASE STUDY: PAH-Contaminated Industrial Site, Southeast China

A field pilot test was conducted at a PAH-contaminated industrial site located in southeast China, where previous applications of chemical oxidants were not effective in reducing PAH concentrations. The E-Redox-In system was applied to soils containing high concentrations of PAHs. After a treatment period of 12 days, results show ~79% decrease in naphthalene and >50% removal of total PAHs. Data also indicated the cleavages of higher polyaromatic rings and a trend of tentative shift towards compounds of less recalcitrance such as naphthalene.

CASE STUDY: TCE-Contaminated Groundwater, Utah

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CASE STUDY: Perchlorate-Contaminated Groundwater

A field pilot test was conducted at a chlorinated solvent-contaminated site located in Utah, where TCE, DCEs, and vinyl chloride are the primary contaminants of concern. The E-Redox-In system was applied to groundwater sediments, and results indicated enhanced back diffusion, which would result in high reduction rates indicated by high production of ethene. After 47 days, the ethene production was 15 times higher than the baseline concentration, which resulted in equivalent TCE and DCEs reduction rates of 1187 and 876 µg/L/day, respectively.

Laboratory E-Redox-In tests were conducted using groundwater contaminated with perchlorate. The test units utilized electrodes processed using the AET proprietary treatment. Direct current (DC) and alternating current (AC) sources provided the electrical requirements for the E-Redox-In electric field. After 40 hours, the E-Redox-In test unit connected to 12 VDC yielded 53.0 % reduction of perchlorate. Additionally, the sulfate was also observed to reduced by the E-Redox-In system, where 84.6% of the sulfate was reduced.

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AboutUsAdvanced Environmental Technologies, LLC (AET) is a technology innovator and implementer, specializing in sustainable treatment solutions for wastewater, contaminated soils, groundwater, and sediments. Our patented and patent-pending technologies focus on remediation of a variety of recalcitrant contaminants, wastewater treatment, and low-value compounds to energy conversion. We provide both technologies and specialized services to project owners and engineering companies by offering innovative and sustainable solutions for environmental remediation, wastewater treatment, and bioenergy.

The AET team consists of scientists and engineers with decades of expertise in environmental biology, biochemistry, chemical engineering, environmental engineering, geochemistry, and soil sciences. Our achievements in science and technology are attested by 150+ publications in professional journals and conferences and 20+ awarded and pending patents, as well as dozens of industrial case studies involving innovative and cost-effective solutions to the most challenging environmental and energy production projects. Our specialized technologies and services include:

• E-Redox-Out: Rapidly degrades contaminants in soils and groundwater, with NO ENERGY INPUT and even generating electricity during operation.

• E-Redox-In: Rapidly reduces chlorinated ethenes, explosive compounds, hexavalent chromium, nitrate, perchlorate, and uranium without accumulation of hazardous intermediates.

• ExBEC: Rapidly degrades contaminants in municipal and industrial wastewaters, with NO ENERGY INPUT and even generating electricity during operation

• BST: Treats acid mine/rock drainage at the source by blocking the acid- generating pathway.

• MetX: Immobilizes and stabilizes toxic heavy metals in soils, sediments, and sludge.

• Kleen: Specifically removes microorganisms (e.g., bacteria) from water. • GIST: Biologically convert low grade coal and other carbonaceous materials into

natural gas • BGF: Produces clean energy (e.g., CH4) and fertilizers from biocatalytical

conversion of biomass and other carbonaceous waste, realizing both financial and environmental gains.

• BEG: Purges gas and prevents new gas formation in coal mines, offering a cost-effective tool for mining safety.

• Remediation Products: Distributes cost-competitive nutrients, oxidizing and reducing compounds for remediation applications.

For additional information on our products and services, please contact us:

Advanced Environmental Technologies, LLC 4025 Automation Way, Suite F4

Fort Collins, CO 80525, USA Tel: +1-970-449-9422

E-mail: info@aetecs.com URL: www.aetecs.com

AdvancedEnvironmentalTechnologies,LLC

Tel: +1-970-449-9422 Email: info@aetecs.com

4025 Automation Way, Suite F4 Fort Collins, Colorado 80525, USA

AET