Hydrogen and Methane Production from Anaerobic Co-Digestion of Sorghum and Cow Manure: Effect of pH and Hydraulic Retention Time
The need for alternative energy sources is constantly growing worldwide, while the focus has shifted to the valorization of biomass. The aim of the present study was to determine the optimal pH and hydraulic retention time (HRT) values for treating a mixture of sorghum biomass solution with liquid c...
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MDPI AG
2022-06-01
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| Series: | Fermentation |
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| Online Access: | https://www.mdpi.com/2311-5637/8/7/304 |
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| author | Margarita A. Dareioti Konstantina Tsigkou Aikaterini I. Vavouraki Michael Kornaros |
| author_facet | Margarita A. Dareioti Konstantina Tsigkou Aikaterini I. Vavouraki Michael Kornaros |
| author_sort | Margarita A. Dareioti |
| collection | DOAJ |
| description | The need for alternative energy sources is constantly growing worldwide, while the focus has shifted to the valorization of biomass. The aim of the present study was to determine the optimal pH and hydraulic retention time (HRT) values for treating a mixture of sorghum biomass solution with liquid cow manure (in a ratio 95:5 <i>v</i>/<i>v</i>) through anaerobic digestion, in a two-stage system. Batch tests were initially carried out for the investigation of the pH effect on bio-hydrogen and volatile fatty acids (VFA) production. The highest hydrogen yield of 0.92 mol H<sub>2</sub>/mol carbohydrates<sub>consumed</sub> was obtained at pH 5.0, whereas the maximum degradation of carbohydrates and VFA productivity was observed at pH 6.0. Further investigation of the effect of HRT on hydrogen and methane production was carried out. The maximum yield of 1.68 mol H<sub>2</sub>/mol carbohydrates<sub>consumed</sub> was observed at an HRT of 5 d, with H<sub>2</sub> productivity of 0.13 L/L<sub>R</sub>·d. On the other hand, the highest CH<sub>4</sub> production rate of 0.44 L/L<sub>R</sub>·d was achieved at an HRT of 25 d, with a methane yield of 295.3 mL/g VS<sub>added</sub>, whereas at a reduced HRT of 20 d the process exhibited inhibition and/or overload, as indicated by an accumulation of VFAs and decline in CH<sub>4</sub> productivity. |
| first_indexed | 2024-03-09T10:18:57Z |
| format | Article |
| id | doaj.art-0f38dd779f7346bfa1dcc8dbd3d1be5c |
| institution | Directory Open Access Journal |
| issn | 2311-5637 |
| language | English |
| last_indexed | 2024-03-09T10:18:57Z |
| publishDate | 2022-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Fermentation |
| spelling | doaj.art-0f38dd779f7346bfa1dcc8dbd3d1be5c2023-12-01T22:08:12ZengMDPI AGFermentation2311-56372022-06-018730410.3390/fermentation8070304Hydrogen and Methane Production from Anaerobic Co-Digestion of Sorghum and Cow Manure: Effect of pH and Hydraulic Retention TimeMargarita A. Dareioti0Konstantina Tsigkou1Aikaterini I. Vavouraki2Michael Kornaros3Department of Chemical Engineering, University of Patras, 1 Karatheodori Str., University Campus, 26500 Patras, GreeceDepartment of Chemical Engineering, University of Patras, 1 Karatheodori Str., University Campus, 26500 Patras, GreeceDepartment of Agriculture, School of Agricultural Science, Hellenic Mediterranean University, 71004 Heraklion-Crete, GreeceDepartment of Chemical Engineering, University of Patras, 1 Karatheodori Str., University Campus, 26500 Patras, GreeceThe need for alternative energy sources is constantly growing worldwide, while the focus has shifted to the valorization of biomass. The aim of the present study was to determine the optimal pH and hydraulic retention time (HRT) values for treating a mixture of sorghum biomass solution with liquid cow manure (in a ratio 95:5 <i>v</i>/<i>v</i>) through anaerobic digestion, in a two-stage system. Batch tests were initially carried out for the investigation of the pH effect on bio-hydrogen and volatile fatty acids (VFA) production. The highest hydrogen yield of 0.92 mol H<sub>2</sub>/mol carbohydrates<sub>consumed</sub> was obtained at pH 5.0, whereas the maximum degradation of carbohydrates and VFA productivity was observed at pH 6.0. Further investigation of the effect of HRT on hydrogen and methane production was carried out. The maximum yield of 1.68 mol H<sub>2</sub>/mol carbohydrates<sub>consumed</sub> was observed at an HRT of 5 d, with H<sub>2</sub> productivity of 0.13 L/L<sub>R</sub>·d. On the other hand, the highest CH<sub>4</sub> production rate of 0.44 L/L<sub>R</sub>·d was achieved at an HRT of 25 d, with a methane yield of 295.3 mL/g VS<sub>added</sub>, whereas at a reduced HRT of 20 d the process exhibited inhibition and/or overload, as indicated by an accumulation of VFAs and decline in CH<sub>4</sub> productivity.https://www.mdpi.com/2311-5637/8/7/304anaerobic digestionpHhydraulic retention timesorghumcow manuretwo-stage system |
| spellingShingle | Margarita A. Dareioti Konstantina Tsigkou Aikaterini I. Vavouraki Michael Kornaros Hydrogen and Methane Production from Anaerobic Co-Digestion of Sorghum and Cow Manure: Effect of pH and Hydraulic Retention Time Fermentation anaerobic digestion pH hydraulic retention time sorghum cow manure two-stage system |
| title | Hydrogen and Methane Production from Anaerobic Co-Digestion of Sorghum and Cow Manure: Effect of pH and Hydraulic Retention Time |
| title_full | Hydrogen and Methane Production from Anaerobic Co-Digestion of Sorghum and Cow Manure: Effect of pH and Hydraulic Retention Time |
| title_fullStr | Hydrogen and Methane Production from Anaerobic Co-Digestion of Sorghum and Cow Manure: Effect of pH and Hydraulic Retention Time |
| title_full_unstemmed | Hydrogen and Methane Production from Anaerobic Co-Digestion of Sorghum and Cow Manure: Effect of pH and Hydraulic Retention Time |
| title_short | Hydrogen and Methane Production from Anaerobic Co-Digestion of Sorghum and Cow Manure: Effect of pH and Hydraulic Retention Time |
| title_sort | hydrogen and methane production from anaerobic co digestion of sorghum and cow manure effect of ph and hydraulic retention time |
| topic | anaerobic digestion pH hydraulic retention time sorghum cow manure two-stage system |
| url | https://www.mdpi.com/2311-5637/8/7/304 |
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