Process Performance and Biogas Output: Impact of Fluctuating Acetate Concentrations on Methanogenesis in Horizontal Anaerobic Reactors

The influence of introducing fluctuations in acetate feeding concentrations on the process stability of a lab-scale horizontal anaerobic reactor (HAR) was investigated to ascertain its effects on acetoclastic methanogenesis. Acetate concentrations were randomized at 85 g COD/L ± 20% and discontinuou...

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Main Authors: Jovale Vincent Tongco, Md Abu Hanifa Jannat, Sangmin Kim, Sang Hyeok Park, Seokhwan Hwang
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Energies
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Online Access:https://www.mdpi.com/1996-1073/18/12/3120
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author Jovale Vincent Tongco
Md Abu Hanifa Jannat
Sangmin Kim
Sang Hyeok Park
Seokhwan Hwang
author_facet Jovale Vincent Tongco
Md Abu Hanifa Jannat
Sangmin Kim
Sang Hyeok Park
Seokhwan Hwang
author_sort Jovale Vincent Tongco
collection DOAJ
description The influence of introducing fluctuations in acetate feeding concentrations on the process stability of a lab-scale horizontal anaerobic reactor (HAR) was investigated to ascertain its effects on acetoclastic methanogenesis. Acetate concentrations were randomized at 85 g COD/L ± 20% and discontinuously fed in the duplicate HARs for five days per week (giving the system time to rest and equilibrate for two days). The reactors were monitored daily with respect to performance indicators (physicochemical variables). The residual acetate concentration was observed to fluctuate at the initial stages, followed by a converging trend (decrease in variance) until the end of operation. Furthermore, letting the system self-neutralize and equilibrate during rest days resulted in improved process performance. The daily acetate degradation efficiency at ~90% and methane concentration at ~60% were attained after operating the reactors for 80 days. The results divulged that introducing fluctuations in acetate feeding concentrations does not affect the stability of biogas production and methane concentration. The acclimatization of the methanogenic population (predominantly <i>Methanosaeta,</i> then shifting to <i>Methanosarcina</i>) was also observed.
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spelling doaj-art-a8b56df3fb6243aa9e203d650855ca0a2025-08-20T02:24:43ZengMDPI AGEnergies1996-10732025-06-011812312010.3390/en18123120Process Performance and Biogas Output: Impact of Fluctuating Acetate Concentrations on Methanogenesis in Horizontal Anaerobic ReactorsJovale Vincent Tongco0Md Abu Hanifa Jannat1Sangmin Kim2Sang Hyeok Park3Seokhwan Hwang4Department of Forest, Rangeland and Fire Sciences, University of Idaho, 875 Perimeter Dr, Moscow, ID 83844, USADivision of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang 37673, Republic of KoreaDivision of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang 37673, Republic of KoreaDivision of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang 37673, Republic of KoreaDivision of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang 37673, Republic of KoreaThe influence of introducing fluctuations in acetate feeding concentrations on the process stability of a lab-scale horizontal anaerobic reactor (HAR) was investigated to ascertain its effects on acetoclastic methanogenesis. Acetate concentrations were randomized at 85 g COD/L ± 20% and discontinuously fed in the duplicate HARs for five days per week (giving the system time to rest and equilibrate for two days). The reactors were monitored daily with respect to performance indicators (physicochemical variables). The residual acetate concentration was observed to fluctuate at the initial stages, followed by a converging trend (decrease in variance) until the end of operation. Furthermore, letting the system self-neutralize and equilibrate during rest days resulted in improved process performance. The daily acetate degradation efficiency at ~90% and methane concentration at ~60% were attained after operating the reactors for 80 days. The results divulged that introducing fluctuations in acetate feeding concentrations does not affect the stability of biogas production and methane concentration. The acclimatization of the methanogenic population (predominantly <i>Methanosaeta,</i> then shifting to <i>Methanosarcina</i>) was also observed.https://www.mdpi.com/1996-1073/18/12/3120anaerobic digestionhorizontal reactoracetoclastic methanogenesissubstrate concentration fluctuationmicrobial community analysis
spellingShingle Jovale Vincent Tongco
Md Abu Hanifa Jannat
Sangmin Kim
Sang Hyeok Park
Seokhwan Hwang
Process Performance and Biogas Output: Impact of Fluctuating Acetate Concentrations on Methanogenesis in Horizontal Anaerobic Reactors
Energies
anaerobic digestion
horizontal reactor
acetoclastic methanogenesis
substrate concentration fluctuation
microbial community analysis
title Process Performance and Biogas Output: Impact of Fluctuating Acetate Concentrations on Methanogenesis in Horizontal Anaerobic Reactors
title_full Process Performance and Biogas Output: Impact of Fluctuating Acetate Concentrations on Methanogenesis in Horizontal Anaerobic Reactors
title_fullStr Process Performance and Biogas Output: Impact of Fluctuating Acetate Concentrations on Methanogenesis in Horizontal Anaerobic Reactors
title_full_unstemmed Process Performance and Biogas Output: Impact of Fluctuating Acetate Concentrations on Methanogenesis in Horizontal Anaerobic Reactors
title_short Process Performance and Biogas Output: Impact of Fluctuating Acetate Concentrations on Methanogenesis in Horizontal Anaerobic Reactors
title_sort process performance and biogas output impact of fluctuating acetate concentrations on methanogenesis in horizontal anaerobic reactors
topic anaerobic digestion
horizontal reactor
acetoclastic methanogenesis
substrate concentration fluctuation
microbial community analysis
url https://www.mdpi.com/1996-1073/18/12/3120
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