Behavior of sulfate-reducing bacteria in single-stage anaerobic digesters pretreated with ozone

Tuncay, Sera
Akcakaya, Merve
İçgen, Bülent
Anaerobic digestion is a solid stabilization process commonly used at both municipal and industrial wastewater and sludge treatment. Anaerobic digesters convert the microbiological cells and other solids generated during the treatment process to a stable end product and also produce methane-rich biogas as an energy source through the degradation of organic matter. Microbial population dynamics involved in anaerobic digestion are not well-studied yet due to the requirement of an extensive investigation of microorganisms, their mechanisms and their relations to each other. There are four successive stages of anaerobic digestion as hydrolysis, acidogenesis, acetogenesis and methanogenesis which are governed by hydrolytic microorganisms, acidogens, acetogens and methanogens. Ozone pretreatment to anaerobic digestion promotes the hydrolysis stage by enhancing methane production ability of methanogens. In anaerobic digestion, sulfates and other sulfur oxides are easily reduced to sulfides especially to hydrogen sulfide (H2S) by sulfate-reducing bacteria (SRB). In the presence of sulfate at considerable levels, this sulfate reduction process dominates over methanogenesis since sulfate reducers and methanogens compete for the similar substrates. Besides, H2S as the end-product of the process, has an inhibitory effect to methanogens and other microbial communities because of its toxicity. In this study, 0.03, 0.06 and 0.09 g O3/g TSS ozone doses were applied to single-stage mesophilic anaerobic digesters in order to observe the improvement in methane production. The effects of these ozone doses on SRB and their role in methane production were examined. Community analysis for the sulfate reducers were performed with Fluorescence in situ Hybridization (FISH) method. As a result of the study, sulfate reducers dominated for the digester pretreated with 0.03 g O3/g TSS ozone dose day by day, while sulfate reducers in the other digesters remained same and did not show a significant change during the operation.
4th International Energy & Engineering Congress (UEMK 2019), 24-25 October 2019


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Citation Formats
S. Tuncay, M. Akcakaya, and B. İçgen, “Behavior of sulfate-reducing bacteria in single-stage anaerobic digesters pretreated with ozone,” Gaziantep, Turkey, 2019, p. 546, Accessed: 00, 2021. [Online]. Available: