MTBE Demonstration Project

Introduction

Methyl tertiary butyl ether (MTBE) has been identified as a contaminant in groundwater aquifers in many states across the U.S. The EPA Drinking Water Provisional Health Advisory is 20-40 μ/L (micrograms per liter). In a survey of sites conducted by Chevron, MTBE concentrations exceeded 1000 μg/L in 47% of 251 California sites surveyed, 63% of 153 Texas sites surveyed, and 81% of 41 Maryland sites surveyed. More information is needed on the most cost-effective ways to treat MTBE at contaminated sites and in drinking water.

Project Background

EPA has assembled a workgroup¹ to conduct field evaluations of technologies and processes to treat drinking water (or wellhead treatment) and groundwater contaminated with MTBE. The focus of the field demonstrations is to conduct performance evaluations on field-ready technologies and processes for drinking water treatment and for treatment of groundwater and aquifer materials at the source of contamination. The workgroup has solicited for locations to host technology demonstrations. Proposals were due November 11, 1999. The group has selected the Naval Construction Battalion Center, Port Hueneme, California as the host site for both source zone and wellhead treatment technology demonstration and evaluation for MTBE-impacted groundwater.

Demonstration Host Site Solicitation (Closed 11/4/99) (PDF) (9 pp, 37K, About PDF)

Technology Selection

Technologies and processes were selected based on a national solicitation to determine the best available, field-ready systems. Accordingly, the process to assess the key technical issues was deliberate; the competition was open and lengthy enough to ensure adequate notification, response time, and sufficient time for peer review of the proposals.

Solicitation Request (Closed 05/30/00) (PDF) (11 pp, 295K, About PDF)
Request for Applications to Demonstrate Technologies to Treat Methyl-t-Butyl Ether

Fact Sheet on Technology Solicitation (PDF) (2 pp, 432K, About PDF)
tri-fold brochure (EPA/625/F-00/003, April 2000)

Schedule (NOTE: this project has beeen completed...this information is for reference only)

Host Site Selection

Action	Date	Status
Proposals for candidate sites	November 1999	completed
Review of sites completed	December 1999	completed
Selection of host site	April 2000	completed

Technology/Process Selection & Demonstration

Action	Tentative Date	Status
Technology vendor solicitation available	April 17, 2000	available (see below)
Proposals due for candidate technologies/processes	June 9, 2000	completed
Technology selection completed	2001	completed
Begin field demonstration(s)	2001	completed
Project completion reports	2002	completed

Technologies Selected

E-Beam Technology, Haley and Aldrich, Inc.
The E-beam technology uses a beam of high energy electrons to treat contaminated ground water. During treatment, three primary transient reactive species are formed that are reducing and oxidizing: aqueous electrons, hydrogen radicals, and hydroxyl radicals. The vendor claims that these reactive species can destroy organic compounds initially present in the water at the parts-per-million (ppm) range, in most cases, to non-detectable concentrations. Because three reactive species are formed, multiple mechanisms or chemical pathways are present for organic compound destruction. In this way, the E-beam technology differs from other technologies that involve free radical chemistry, which typically rely on a single organic compound for destruction, usually a hydroxyl radical. The entire sequence of reactions between organic compounds and reactive species occurs in the area where the E-beam impacts the water, and is usually completed in milliseconds. The technology is being demonstrated for wellhead and source applications.
HiPOx Process, Applied Process Technology, Inc.

The HiPOx process, developed by APT, is an Advanced Oxidation Process (AOP) that uses ozone and hydrogen peroxide to destroy organic compounds. Ozone dissociates as well as reacts with hydrogen peroxide to produce hydroxyl radicals which react with other organic contaminants, ultimately producing carbon dioxide and water. The HiPOx technology enhances the mass transfer of the ozone into the water by using higher ozone concentrations (8 to 10 % by weight), higher operating pressures (35 to 45 psig) and multiple mixing zones. The vendor claims that installing multiple reaction zones and ports further enhances the process by minimizing the free ozone concentration, and hence the formation of unwanted ozonation byproducts such as bromate.. The technology is being demonstrated for wellhead application.
In Situ Bioremediation of MTBE in Ground Water Using Propane Oxidizing Bacteria, Envirogen, Inc.
This technology injects propane, oxygen, and propane-oxidizing bacteria (POB) into a contaminated aquifer to degrade the MTBE. It is postulated that the stimulation of the POB will result in the production of the propane monooxygenase enzyme. This will catalyze the destruction of MTBE and it's primary breakdown product, tert-butyl alcohol and wil be completely converted to carbon dioxide and water. A network of conventional upgradient and downgradient monitoring points in the aquifer and vadose zone are installed. A ground water tracer mixing and injection system provides two ground water tracers ( bromide and iodide) and deuterated-MTBE. The process is being demonstrated for source treatment.

Project Reports

High Energy Electron Injection (E-Beam) Technology for the Ex-Situ Treatment of MtBE-Contaminated Groundwater - Innovative Technology Evaluation Report (PDF) (85 pp, 1.13MB, About PDF) (EPA 600/R-02/066)
Demonstration of the HiPOx Advanced Oxidation Technology for the Treatment of MTBE-Contaminated Groundwater (PDF) (33 pp, 859K, About PDF) (EPA 600/R-02/094, September 2002)
Envirogen Propane Biostimulation Technology for In-Situ Treatment of MTBE-Contaminated Ground Water - Innovative Technology Evaluation Report (PDF) (18 pp, 322K, About PDF) (EPA 600/R-02/092)

Additional Information

The following EPA web sites have additional information about MTBE:

For more information about MTBE in drinking water, contact the Safe Drinking Water Hotline at 800-426-4791.

¹ This work group consists of staff in the following EPA offices: National Risk Management Research Laboratory (NRMRL); Office of Solid Waste and Emergency Response (OSWER) (Office of Underground Storage Tanks and the Technology Innovation Office); Office of Water (OW); Office of Air Quality Planning and Standards (OAQPS); and Region 9. In addition, the California Water Resources Control Board and the California Department of Health Services are participating on the workgroup. (Return to Text)

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