Title page for ETD etd-09212006-195109


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
  • lignin
  • paper
  • anaerobic biosolids
  • lignin monomers
  • elevated temperature
Date of Defense 2006-09-07
Availability restricted
Abstract
The Effect of Temperature on Lignin Degradation in Municipal Solid Waste

Olga Miroshnikova

Chair: Dr. John T. Novak, Ph.D

(ABSTRACT)

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.

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