IN-SITU BIOTREATMENT OF MTBE: EVALUATION OF TWO OXYGEN ADDITION SYSTEMS

摘要

The observation that the addition of oxygen can lead to stimulation of the biodegradation of fuel oxygenates has rekindled interest in aerobic biobarrier systems. The efficacy of an oxygen addition system depends on its ability to overcome in-situ oxygen demand. One goal of this paper is to discuss key design criteria for aerobic biobarriers. We have proposed a mass balance based approach which focuses on the insitu oxygen demand, as well as, the oxygen supply rate of specific technologies. Definitions of terms and design equations are presented to support the utilization of these concepts in the implementation and operation of remedial systems. As part of ChevronTexaco’s MTBE Technology Demonstration Program we have evaluated two insitu oxygen addition technologies, IsoGen? and the University of Waterloo Diffusive Emitters, at a marketing fuel terminal. Each technology was installed across one half of the plume in a transect of 4-inch wells installed on five (5) and ten (10) foot centers. The target constituents include methyl tert-butyl ether (MTBE), tert-butyl alcohol (TBA), benzene, and total petroleum hydrocarbons. A series of monitoring wells up-gradient and down-gradient of the oxygen addition wells provide monitoring points to evaluate changes in the flux of constituents through the treatment zone. Results and lessons learned over the 1st year of operation at this site are presented.