[{"key":"dc.contributor.author","value":"Kizza, Ronald","language":null},{"key":"dc.date.accessioned","value":"2026-03-20T03:21:41Z","language":null},{"key":"dc.date.available","value":"2026-03-20T08:02:17Z","language":null},{"key":"dc.date.issued","value":"2026","language":"en"},{"key":"dc.identifier.uri","value":"http:\/\/hdl.handle.net\/2429\/93807","language":null},{"key":"dc.description.abstract","value":"Hydrothermal liquefaction (HTL) has emerged as a promising thermochemical technology for converting municipal sludge into biofuels, providing an alternative source of energy and a more space-efficient option compared to conventional sludge treatment methods like composting. However, the implementation of HTL faces a major challenge due to the substantial volume of an aqueous byproduct referred to as hydrothermal liquefaction aqueous phase (HTLaq) it produces, requiring effective management solutions. Anaerobic digestion (AD) has been proposed as a sustainable treatment method for HTLaq, offering the potential for additional energy recovery through methane. However, HTLaq contains toxic compounds that inhibit the AD process, limiting its effectiveness. The inhibition is poorly understood, highlighting the need for comprehensive research to better understand and mitigate these challenges. In this dissertation, various approaches were utilized to develop a deeper understanding of HTLaq inhibitory compounds and their impacts on downstream anaerobic biodegradation processes. First, ultrafiltration (UF) fractionation and biochemical methane potential (BMP) assays were employed to understand the molecular weight distribution (MwD) of HTLaq organics and their impact on biodegradability. Then, anaerobic toxicity assays (ATA) were performed to quantify and compare the relative toxicities of model potential inhibitory compounds commonly found in sludge-derived HTLaq, thereby screening out the most inhibitory compounds. Finally, modeling was employed to predict the inhibition of sludge-derived HTLaq based on the abundance of individual inhibitory compounds.  Results showed that MwD had a significant impact on the rate of anaerobic biodegradability, with the Mw<1 kDa fraction achieving the highest rate (0.53 day\u207b\u00b9). However, the cumulative methane produced from Mw fractions was not statistically significantly different. Based on the ATA results, compounds such as 3-methylcyclopentanone, indole, pyridine, 2-ethylpyridine, 3-aminopyridine, phenol, and 2-aminophenol were identified as the most toxic to both mesophilic and thermophilic AD systems, while pyrazines and \u03b4-valerolactam exhibited minimal inhibition. Modeling using Generalized Additive Models (GAM) revealed that the inhibition of HTLaq can be predicted with reasonable precision based on the concentration of 15 selected constituent compounds. These findings contribute to a deeper understanding of the inhibition of HTLaq during AD treatment and inform strategies for optimizing methane production from sludge-derived HTLaq waste streams.","language":"en"},{"key":"dc.language.iso","value":"eng","language":"en"},{"key":"dc.publisher","value":"University of British Columbia","language":"en"},{"key":"dc.rights","value":"Attribution-NonCommercial-NoDerivatives 4.0 International","language":"*"},{"key":"dc.rights.uri","value":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/","language":"*"},{"key":"dc.title","value":"Insights into the inhibition of anaerobic digestion by hydrothermal liquefaction aqueous phase derived from municipal sludge","language":"en"},{"key":"dc.type","value":"Text","language":"en"},{"key":"dc.degree.name","value":"Doctor of Philosophy - PhD","language":"en"},{"key":"dc.degree.discipline","value":"Civil Engineering","language":"en"},{"key":"dc.degree.grantor","value":"University of British Columbia","language":"en"},{"key":"dc.contributor.supervisor","value":"Eskicioglu, Cigdem","language":null},{"key":"dc.date.graduation","value":"2026-05","language":"en"},{"key":"dc.type.text","value":"Thesis\/Dissertation","language":"en"},{"key":"dc.description.affiliation","value":"Applied Science, Faculty of","language":"en"},{"key":"dc.description.affiliation","value":"Engineering, School of (Okanagan)","language":"en"},{"key":"dc.degree.campus","value":"UBCO","language":"en"},{"key":"dc.description.scholarlevel","value":"Graduate","language":"en"}]