Type of Document Master's Thesis Author Miroshnikova, Olga URN etd-09212006-195109 Title The Effect of Temperature on Lignin Degradation in Municipal Solid Waste Degree Master of Science Department Environmental Engineering Advisory Committee
Advisor Name Title Novak, John T. Committee Chair Goldsmith, C. Douglas Jr. Committee Member Randall, Clifford W. Committee Member Keywords
- anaerobic biosolids
- lignin monomers
- elevated temperature
Date of Defense 2006-09-07 Availability restricted AbstractThe Effect of Temperature on Lignin Degradation in Municipal Solid Waste
Chair: Dr. John T. Novak, Ph.D
Paper and paperboard are the major constituents found in US landfills. Typically paper consists of 79% to 98% of lignocellulose which is considered to be the most abundant source of natural carbon on earth. Lignocellulose decomposition depends on the association of biodegradable cellulose and hemicellulose with lignin. Lignin is a recalcitrant material which hinders cellulose degradation in conventional landfills. Because of this property of lignin cellulose to lignin ratio (C/L) is a common landfill stabilization parameter. Refuse degradation in landfills is a microbiological process and is highly dependent on temperature, moisture, and pH. Bioreactor landfills are designed to enhance biodegradation of refuse by providing favorable conditions for microorganisms. Effect of elevated temperature and moisture on possibility of lignin degradation is studied in this work. Synthetic and newspaper lignin were preheated and then inoculated with anaerobically digested sludge. Newspaper in distilled water exposed to 95°C for 48 hours released 8 times more of solubilized lignin then non preheated newspaper. Moreover lignin monomers were detected as a result of 95°C pretreatment indicating the positive effect of high temperature on the providing lignin in more bioavailable form for microbes. Digested sludge inocula was found to be capable of lignin monomers degradation as well as low but significant mineralization of synthetic lignin with approximately 6% of carbon originated from lignin mineralized into methane and carbon dioxide. An exponentially increasing trend for lignin monomers solubilization as a function of temperature was observed for three types of substrate, synthetic lignin, cardboard, and newspaper with the highest rate of solubilization for newspaper. Results of this study suggest that some lignin degradation can occur at conditions typical for bioreactor landfills.
Filename Size Approximate Download Time (Hours:Minutes:Seconds)
28.8 Modem 56K Modem ISDN (64 Kb) ISDN (128 Kb) Higher-speed Access MSOlgaMiroshnikova.pdf 381.55 Kb 00:01:45 00:00:54 00:00:47 00:00:23 00:00:02indicates that a file or directory is accessible from the Virginia Tech campus network only.
If you have questions or technical problems, please Contact DLA.