Optimizing Biofilter performance on hexane and gasoline contaminated air streamsEPA Grant Number: U914979
Title: Optimizing Biofilter performance on hexane and gasoline contaminated air streams
Investigators: Davidova, Yulya B.
Institution: University of California - Davis
EPA Project Officer: Lee, Sonja
Project Period: January 1, 1996 through July 28, 1997
Project Amount: $68,000
RFA: STAR Graduate Fellowships (1996) RFA Text | Recipients Lists
Research Category: Fellowship - Environmental Engineering , Academic Fellowships , Engineering and Environmental Chemistry
The objective of this research project is to develop and optimize biofilter performance for air streams contaminated with hexane and gasoline by performing a set of experiments designed to determine the performance of biofilter in response to temperature variations. Presently, most biofilters are monitored on a grab-sample basis, and very little information is available on process response to environmental variables. Laboratory systems operate at constant temperature, and literature is virtually empty with respect to temperature effects.
Two factors suggested the relationship between temperature and the performance of the biofilter. First, during the experiments at University of California, Davis, a decrease of microbial population with a decrease of temperature have been observed. The decrease in population impacts the ability of the system to respond to an increase in loading of contaminant. Second, I found that compounds comprising the gasoline are removed sequentially in the biofilter. The more volatile compounds (e.g., pentane and hexane) are removed later in the column compared to more soluble materials (e.g., benzene and toluene). At lower temperatures, the less soluble, more volatile compounds are likely to pass through unremoved, unless design and operation accommodations are made. Biofilters are attractive because of low capital and operating costs. However, if process performance is highly temperature sensitive, monitoring restriction may be appropriate.
The experiments that I will conduct will determine: (1) the effect of temperature on overall emissions from biofilters treating mixtures such as gasoline; (2) the effect of diurnal temperature variation on emissions; and (3) the necessity of diurnal monitoring for biofilters. Biofiltration is a technology in its infancy, and these experiments should define an important parameter for both the particular case of gasoline vapor treatment and for complex mixtures in general.