Date of Award
Master of Science
Department of Systems Engineering and Management
Charles A. Bleckmann, PhD
This research effort was conducted to analyze the biodegradation of propylene glycol (PG) and tolyltriazole in two different soil types; a sandy soil and a high clay soil. Both an automated respirometer and a high performance liquid chromatograph (H PLO) were used in the analysis. Two separate experiments were conducted. In the first experiment, one level of tolyltriazole was added to the soils to determine whether or not there was a difference in the biodegradation rates of tolyltriazole in the two soils. The respirometer results indicated that there was a significant difference between the respiration rates of the microorganisms in the two soil types, and the HPLO results indicated that biodegradation of the tolyltriazole was occurring in the microcosms. In the second experiment, only the high clay soil was used since it had a significantly higher respiration rate than the sandy soil. This experiment was conducted to determine the affect (inhibition, stimulation, or no effect) of a combined treatment of tolyltriazole and PG vs. the contaminants acting by themselves. The soil was treated with tolyltriazole alone, PG alone, and a combined mixture of the two. One level of PG was used throughout, and two levels of tolyltriazole were used, for a total of five different treatments. Both the respirometer and HPLO results indicated that biodegradation was occurring. The respirometer results indicated that there was a significant increase in the respiration rates of the microorganisms when the contaminants were mixed vs. by themselves, thereby indicating an increase in biodegradation. The HPLC results, however, indicated that the same amount of tolyltriazole was biodegrading whether it was in combination with PG or acting alone. These results may indicate that the significant increase in respiration was due to an increase in biodegradation of PG.
DTIC Accession Number
Johnson, Laura M., "Evaluation of the Natural Biodegradation of Aircraft Deicing Fluid Components in Soils" (1997). Theses and Dissertations. 5680.