Date of Award

8-2020

Document Type

Thesis

Degree Name

Master of Science (MS)

College/School

College of Science and Mathematics

Department/Program

Earth and Environmental Studies

Thesis Sponsor/Dissertation Chair/Project Chair

Yang Deng

Committee Member

Huan Feng

Committee Member

Clement Alo

Abstract

Landfilling is the dominant municipal solid waste (MSW) management option in the United States and many other countries. Leachate management and treatment represent an essential component in sustainable management of landfills. However, leachate organic matter (LOM) present in landfill leachate challenges existing treatment practices. The long-term goal of this study is to develop innovative treatment technologies for mitigation of LOM impacts for supporting sustainability in waste management and wastewater treatment. The overall objective of this thesis research aimed to investigate technical performance of the joint use of advanced oxidation process (AOP) and advanced reduction process (ARP) for treatment of mature landfill leachate with a focus on alleviation of LOM. In this study, the Fenton treatment and UV/sulfite process were selected as AOP and ARP, respectively, for treatment of a typical mature leachate.

Laboratory-scale batch tests were performed to evaluate the integrated ARP-AOP design for removal of LOM. LOM was substantially alleviated in the Fenton treatment in terms of chemical oxygen demand (COD), dissolved oxygen carbon (DOC), and UV254 absorbance. At the optimal operational conditions, i.e., pH 5.0, [H2O2]:[Fe2+] = 2:1, and DOD =1, COD and UV254 absorbance were removed by 78% and 75%, respectively. The Fenton-treated leachate was further treated in the ARP system. ARP did not significantly mineralize the recalcitrant LOM, but the LOM degradation was evidenced from the alleviation of UV254 absorbance. The reduction in UV254 absorbance was not obviously affected by pH (8.5 -10.5) in this study, but enhanced with the increasing sulfite dose. The maximum UV254 absorbance achieved in the ARP system (pH 9.5) was 53% in comparison to that after the Fenton treatment. Although further increase in the sulfite dose did not markedly translate into the improvement in the overall UV254 absorbance, LOM characterization tests suggested, as the sulfite dose increased, more high molecular weight (MW) compounds were degraded to low MW molecules, while the UV254 absorbance contributed from hydrophobic LOM declined. This study represented the first study on application of ARPs for treatment of landfill leachate. Meanwhile, a new treatment train in the combination of AOP and ARP was proposed and tested for alleviation of LOM. This study clearly demonstrates that the propose LOM treatment method is a promising approach to addressing LOM impacts for supporting sustainable management of landfill leachate.

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