Aerobic trichloroethylene biodegradation in continuous-recycle expanded-bed bioreactors

Author

John Joseph Niedzielski

Date of Award

12-1988

Degree Type

Thesis

Degree Name

Master of Science

Major

Life Sciences

Major Professor

David C. White

Committee Members

Thommy J. Phelps, Stephen E. Herbes, Walter Farkas

Abstract

Chlorinated aliphatic hydrocarbons pose a serious threat to our fresh water supplies. Their toxic effects are well documented and their abundant use in industrial processes and commercial products has led to widespread environmental contamination. Present water treatment processes are not desirable since the chlorinated compounds are not destroyed, but are merely removed and transferred to other portions of the environment. In the atmosphere, chlorinated hydrocarbons undergo transformations in the ozone layer leading to the formation of other chlorinated intermediates.

Recently, it has been discovered that certain microorganisms have the ability to biologically transform some chlorinated aliphatics to non-toxic compounds such as carbon dioxide. Test cultures capable of degrading trichloroethylene (TCE) at concentrations up to 100 mg/L have been maintained successfully in this laboratory. The present research has investigated the feasibility of utilizing these TCE-degrading cultures in continuous recycle expanded-bed bioreactors capable of degrading TCE aerobically at concentrations of 20 mg/L. Two solid support matrices were compared and two different mixed culture consortia were utilized for bioreactor degradation studies. Operating reactors were subjected to a number of test conditions in which parameters including energy source, pH, and nutrient levels were altered. The reactors were shown to be an effective means of monitoring the biological transformation of TCE occurring within these enclosed systems. Greater than 90% removal of TCE at initial liquid phase concentrations of 20 mg/L was observed in test reactors after 5 days, while control reactors contained 98% of the initial TCE added.

Recommended Citation

Niedzielski, John Joseph, "Aerobic trichloroethylene biodegradation in continuous-recycle expanded-bed bioreactors. " Master's Thesis, University of Tennessee, 1988.
https://trace.tennessee.edu/utk_gradthes/13287