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dc.contributor.authorIrani, Ayeshaen_US

The objective of this study was to determine how the key features of bioreactor landfills; increased temperature, moisture and microbial activity, affect the biological stability of the landfill material. In the first part of the study the solubilization and degradation of lignin in paper exposed to these bioreactor landfill conditions are explored. The solubility of the lignin in paper was observed at different temperatures and over 27 weeks at 55°C and the anaerobic bioconversion of office paper, cardboard and Kraft lignin was observed in bench-scale reactors over 8 weeks. As the temperature rose, lignin solubility increased exponentially. With extended thermal treatment, the dissolution of lignin continues at a constant rate. This rate increases 15 times for paper and 1.5 times for cardboard in the presence of rumen inoculum compared to un-inoculated systems. At around 6 weeks the inter-monomeric linkages between the solubilized lignin molecules began breaking down, releasing monomers. In cardboard and Kraft lignin, a significant amount of the monomers mineralize to CO2 and CH4 during this time period. The results indicate that small, but significant rates of lignin solubilization and anaerobic lignin degradation are likely to occur in bioreactor landfills due to both higher temperature and microbial activity.

In the second part of the study, field data from the Outer Loop Recycling and Disposal Facility in Louisville, Kentucky was evaluated to determine the effectiveness of an anaerobic-aerobic landfill bioreactor (AALB) vs. the control landfill that is managed as a traditional landfill. Moisture, temperature, elevation and the amount of time the MSW has spent in the landfills (age) were measured and compared to determine the factors that affect the biological stability of the landfill. The results showed that the MSW in the AALB is more biologically stable than the MSW in the control landfill, indicating that they are more degraded. Additionally, elevation or location of the MSW was the key factor in determining the extent of MSW stability within the AALB and temperature is the key factor in determining the biological stability of the MSW in the control landfill. Higher temperatures correlated with a more biologically stable waste. The cellulose to lignin ratio (C/L ratio) and biochemical methane potential (BMP) were the main biological stability parameters used.

dc.publisherVirginia Techen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectCellulose/Lignin Ratioen_US
dc.subjectBioreactor Landfillsen_US
dc.subjectSoluble Ligninen_US
dc.titleBiochemical Lignin Related Processes in Landfillsen_US
dc.contributor.departmentEnvironmental Engineeringen_US
dc.description.degreeMaster of Scienceen_US of Scienceen_US Polytechnic Institute and State Universityen_US Planningen_US
dc.contributor.committeechairNovak, John T.en_US
dc.contributor.committeememberGoldsmith, C. Douglas Jr.en_US
dc.contributor.committeememberKnowlton, Katharine F.en_US
dc.contributor.committeememberEvanylo, Gregory K.en_US

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