Effect of ozone pretreatment on methane production and microbial community structure of single-stage anaerobic digesters

2021-2-09
Tuncay, Sera
Increasing amount of sludge produced by wastewater treatment plants poses many problems in environmental, public health and economic aspects. Anaerobic digestion (AD), the most common sludge stabilization method, is used to reveal energy potential of sludge as methane-rich biogas. Various pretreatment methods are applied to enhance AD efficiency by facilitating the rate limiting hydrolysis step. Ozone pretreatment is a remarkable method for improving methane production, sludge reduction and pathogen removal. Therefore, this study investigated the effect of ozone pretreatment with varying doses of 0.03, 0.06 and 0.09 g O3/g TSS on methane production and microbial communities of mesophilic single-stage anaerobic digesters operated as semi-batch. Anaerobic digesters were monitored in terms of pH, temperature, chemical oxygen demand, total nitrogen, solids content, total volatile fatty acids, methane production and microbial community structure. Changes in methane and microbial community structure were determined by gas chromatography and fluorescence in situ hybridization (FISH) methods, respectively. Pretreatment with 0.06 g O3/g TSS resulted in 47% methane increase by achieving the highest methane content of 78%. FISH analyses revealed that Methanosaeta spp. were the most dominant methanogens in this pretreated digester.

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Citation Formats
S. Tuncay, “Effect of ozone pretreatment on methane production and microbial community structure of single-stage anaerobic digesters,” M.S. - Master of Science, Middle East Technical University, 2021.