Application of thermal hydrolysis for advanced anaerobic digestion of the City of Kelowna’s biosolids

Description:Application of thermal hydrolysis for advanced anaerobic digestion of the City of Kelowna’s biosolids. Presenter: Ehssan Hosseini Koupaie, University of British Columbia Okanagan Campus. Additional Contributors: Cigdem Eskicioglu, P.Eng., Ph.D., UBC Okanagan, Kelowna, BC. In recent years, the City of Kelowna has begun to investigate ways to further reduce the amount of the biosolids generated at a rate of 60 dry tons/day at Kelowna’s wastewater treatment plant (WWTP). Currently, the biosolids are trucked to a composting facility in Vernon where it is mixed with wood chips to produce a commercial fertilizer, Ogogrow. However, due to the limited capacity of the composting site, investigation of new biosolids management options is essential. One option under consideration is the implementation of an anaerobic digester at Kelowna’s WWTP. Anaerobic digestion is a biological process in which the organic waste is converted into methane-rich biogas and fertilizer in an oxygen-free environment. Under this scenario, methane recovered from the biosolids can be utilized for electricity generation. The bottleneck of conventional anaerobic digestion is slow degradation of complex organic waste such as biosolids, requiring long retention time and large digester volume. In this study, thermal hydrolysis using microwave and conductive heating was applied on Kelowna’s biosolids to disrupt its structure prior to being digested. The biosolids solubilization (disintegration) ratio was improved up to 5, 6.8, 3.1 and 2.9 times in terms of COD, sugar, protein and humic acid after thermal hydrolysis. Up to 58.1% and 70.2% of total and volatile solids were removed in the digesters fed with thermally hydrolyzed biosolids, respectively. The maximum biogas yield (534 ml/g VS-added) was achieved at the optimum thermal hydrolysis condition resulting in more than 10% improvement in methane production (over the control digester).

Authors: Ehssan Hosseini Koupaie

Subjects: Wastewater

Tags:AC15,2015 BCWWA Annual Conference & Trade Show,2015 Annual Conference,AC15 presentations

Citation:Stream 3: Resource Recovery

Publication Date:May 28th, 2015 Upload Date:Jun 25th, 2015

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