Anuja Sapkota

ORCID Identifier(s)

0000-0002-6059-2795

Graduation Semester and Year

2017

Language

English

Document Type

Thesis

Degree Name

Master of Science in Civil Engineering

Department

Civil Engineering

First Advisor

Sahadat Hossain

Abstract

More than half of total Municipal Solid Waste (MSW) generated is composed of organic degradable waste for developed countries and the percentage is even higher for developing countries. Handling of organic fraction of MSW has always been challenging due to environmental and economic reasons. Among all the MSW management alternatives, Sustainable Biocell concept has potential to solve environmental and economic concerns related to organic waste. This potential of Sustainable Biocell can be enhanced by accelerated decomposition of waste. Accelerated decomposition of organic fraction of MSW can be achieved by the addition of nitrogen rich, macro and micro nutrients such as sludge and manures. Several studies have been conducted by using either sludge or animal’s manures as inoculum for degrading organic fraction of MSW in the anaerobic digester. However, the study to compare the performance of different manures combined with sludge on the degradation of organic fraction of MSW has not been conducted on laboratory simulated Biocell reactors. Also, the effects of different types of manure on degradation of organic fraction of MSW have not been compared with the lignocellulos enzyme. Therefore, this study was conducted with the objective of finding the effects of addition of sludge-manure and sludge-enzyme in the degradation of organic fraction of MSW within laboratory simulated Biocell environment and comparing them. In this study, five sets of reactors were prepared with selected organic fraction of MSW and inoculum composition. The reactors were operated in the environmental growth chamber at 37ºC and were monitored regularly. The pH, BOD and COD tests were conducted on generated leachate along with gas composition and gas volume measurement. Based on the experimental results, reactors with Manganese Peroxidase (MnP) and pig manure as inoculum presented better result compared to reactors with cow manure and horse manure. The highest volume of methane was generated by reactors designated as A9 and A10 with MnP, produced 54.7 L/lb. and 52.03 L/lb. with peak methane yield of 1.33 and 1.57 L/lb./day respectively. The reactors designated as A5 and A6, with pig manure produced 47.26 L/lb. and 45.91 L/lb. with peak methane yield 1.45 and 1.30 L/lb./day respectively. And, the percentage of volatile solids removal was found to be 77.01% and 77.2% for reactors A9 and A10 with MnP respectively and 75.09 and 76.87% for reactors A5 and A6 with pig manure. Therefore, based on the experimental study, it was determined that MnP and pig manure have the potential to be utilized as inoculum for improving the degradation of waste. Even though MnP enzyme helped to degrade more waste and yielded the highest quantity of methane, it is not considered an economical solution for field application due to high costs of MnP enzyme. Therefore, pig manure is suggested as an economical inoculum for Sustainable Biocell landfill.

Keywords

Organic waste, Municipal solid waste, MSW, Biocell, Inoculum addition, Manure, Leachate recirculation, Enzyme augmentation, Methane generation

Disciplines

Civil and Environmental Engineering | Civil Engineering | Engineering

Comments

Degree granted by The University of Texas at Arlington

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