The Phase I objective is to develop a biodegradation system for treatment of groundwater contaminated by methyl tert-butyl ether (MTBE) and other hydrocarbons. MTBE is the oxygenate of choice by gasoline refiners in the United States and Europe. Reformulated gasoline contains 11 to 15 percent MTBE based on the air quality designation within the distribution area. MTBE is becoming the driving force behind groundwater remediation projects associated with leaking underground storage tanks. In California alone, there are more than 25,000 leaking underground storage tank sites. Because of the low volatility and an octanol-water partition coefficient that is two or three orders of magnitude lower than those of benzene, toluene, ethylbenzene, and xylene (BTEX) compounds, air stripping and sorption of MTBE from groundwater are difficult. These properties result in unusually large capital and operating costs. Biodegradation of MTBE can greatly reduce the cost of its remediation. Environmental Resolutions, Inc. (ERI) and the University of California, Davis, tested mixed and pure MTBE-degrading microbial cultures for their ability to degrade MTBE and other gasoline components. Preliminary studies have investigated the trickling filter (attached growth) type processes for treatment of groundwater containing MTBE and BTEX. Results have been promising. Data indicate that startup was rapid, and good removals were attained within 2 weeks. Specifically, work will include: (1) development of an appropriate process schematic for a pump and treat biological system to remove MTBE from groundwater; (2) determination of the relative efficacy of mixed and pure cultures in biodegrading MTBE under field conditions where other petroleum hydrocarbons are present; (3) development of a startup process for a prototype system; and (4) determination of the efficacy of growing MTBE degrading cultures on ethanol. The experiments will be divided into two groups-field process development and fluidized culture performance evaluation. The major effort will be directed toward the field process development at an MTBE-contaminated site. ERI expects that the project will result in an ability to design prototype units for placement at other MTBE contaminated sites. In a future Phase II project, a full-scale unit will be constructed, installed, and operated at an MTBE-impacted site. Information obtained from this study will allow existing clients and other responsible parties, regulators, and remediation firms to apply ex situ biological treatment.
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Keywords: small business, SBIR, remediation, groundwater, treatment, leaking underground storage tanks, engineering, chemistry, EPA
