Optimisation of Biogas Production in the Co-Digestion of Pre-Hydrodynamically Cavitated Aerobic Granular Sludge with Waste Fats
The characteristics of excess aerobic granular sludge, related to its structure and chemical composition, limit the efficiency of anaerobic digestion. For this reason, pre-treatment methods and compositions with other organic substrates are used. In earlier work, no attempt was made to intensify the...
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2024-02-01
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| Online Access: | https://www.mdpi.com/1996-1073/17/4/922 |
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| author | Marcin Dębowski Marcin Zieliński Joanna Kazimierowicz Anna Nowicka Magda Dudek |
| author_facet | Marcin Dębowski Marcin Zieliński Joanna Kazimierowicz Anna Nowicka Magda Dudek |
| author_sort | Marcin Dębowski |
| collection | DOAJ |
| description | The characteristics of excess aerobic granular sludge, related to its structure and chemical composition, limit the efficiency of anaerobic digestion. For this reason, pre-treatment methods and compositions with other organic substrates are used. In earlier work, no attempt was made to intensify the methane fermentation of the excess aerobic granular sludge by adding fatty waste materials. The aim of the research was to determine the effects of co-digestion of pre-hydrodynamically cavitated aerobic granular sludge with waste fats on the efficiency of methane fermentation under mesophilic and thermophilic conditions. The addition of waste fats improved the C/N ratio and increased its value to 19. Under mesophilic conditions, the highest effects were observed when the proportion of volatile solids from waste fats was 25%. The amount of biogas produced increased by 17.85% and CH<sub>4</sub> by 19.85% compared to the control. The greatest effects were observed in thermophilic anaerobic digestion at 55 °C, where a 15% waste fat content in volatile solids was ensured. This resulted in the production of 1278.2 ± 40.2 mL/gVS biogas and 889.4 ± 29.7 mL/gVS CH<sub>4</sub>. The CH<sub>4</sub> content of the biogas was 69.6 ± 1.3%. The increase in biogas and CH<sub>4</sub> yield compared to pure aerobic granular sludge anaerobic digestion was 34.4% and 40.1%, respectively. An increase in the proportion of waste fats in the substrate had no significant effect on the efficiency of methane fermentation. Strong positive correlations (R<sup>2</sup> > 0.9) were observed between biogas and CH<sub>4</sub> production and the C/N ratio and VS concentration. |
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| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-03-07T22:34:01Z |
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| series | Energies |
| spelling | doaj.art-df4145cdf7dc45f7856128589ae0366e2024-02-23T15:15:26ZengMDPI AGEnergies1996-10732024-02-0117492210.3390/en17040922Optimisation of Biogas Production in the Co-Digestion of Pre-Hydrodynamically Cavitated Aerobic Granular Sludge with Waste FatsMarcin Dębowski0Marcin Zieliński1Joanna Kazimierowicz2Anna Nowicka3Magda Dudek4Department of Environment Engineering, Faculty of Geoengineering, University of Warmia and Mazury in Olsztyn, Str. Oczapowskiego 5, 10-719 Olsztyn, PolandDepartment of Environment Engineering, Faculty of Geoengineering, University of Warmia and Mazury in Olsztyn, Str. Oczapowskiego 5, 10-719 Olsztyn, PolandDepartment of Water Supply and Sewage Systems, Faculty of Civil Engineering and Environmental Sciences, Bialystok University of Technology, 15-351 Bialystok, PolandDepartment of Environment Engineering, Faculty of Geoengineering, University of Warmia and Mazury in Olsztyn, Str. Oczapowskiego 5, 10-719 Olsztyn, PolandDepartment of Environment Engineering, Faculty of Geoengineering, University of Warmia and Mazury in Olsztyn, Str. Oczapowskiego 5, 10-719 Olsztyn, PolandThe characteristics of excess aerobic granular sludge, related to its structure and chemical composition, limit the efficiency of anaerobic digestion. For this reason, pre-treatment methods and compositions with other organic substrates are used. In earlier work, no attempt was made to intensify the methane fermentation of the excess aerobic granular sludge by adding fatty waste materials. The aim of the research was to determine the effects of co-digestion of pre-hydrodynamically cavitated aerobic granular sludge with waste fats on the efficiency of methane fermentation under mesophilic and thermophilic conditions. The addition of waste fats improved the C/N ratio and increased its value to 19. Under mesophilic conditions, the highest effects were observed when the proportion of volatile solids from waste fats was 25%. The amount of biogas produced increased by 17.85% and CH<sub>4</sub> by 19.85% compared to the control. The greatest effects were observed in thermophilic anaerobic digestion at 55 °C, where a 15% waste fat content in volatile solids was ensured. This resulted in the production of 1278.2 ± 40.2 mL/gVS biogas and 889.4 ± 29.7 mL/gVS CH<sub>4</sub>. The CH<sub>4</sub> content of the biogas was 69.6 ± 1.3%. The increase in biogas and CH<sub>4</sub> yield compared to pure aerobic granular sludge anaerobic digestion was 34.4% and 40.1%, respectively. An increase in the proportion of waste fats in the substrate had no significant effect on the efficiency of methane fermentation. Strong positive correlations (R<sup>2</sup> > 0.9) were observed between biogas and CH<sub>4</sub> production and the C/N ratio and VS concentration.https://www.mdpi.com/1996-1073/17/4/922anaerobic digestionaerobic granular sludgewaste fatsco-digestionbiogasmethane |
| spellingShingle | Marcin Dębowski Marcin Zieliński Joanna Kazimierowicz Anna Nowicka Magda Dudek Optimisation of Biogas Production in the Co-Digestion of Pre-Hydrodynamically Cavitated Aerobic Granular Sludge with Waste Fats Energies anaerobic digestion aerobic granular sludge waste fats co-digestion biogas methane |
| title | Optimisation of Biogas Production in the Co-Digestion of Pre-Hydrodynamically Cavitated Aerobic Granular Sludge with Waste Fats |
| title_full | Optimisation of Biogas Production in the Co-Digestion of Pre-Hydrodynamically Cavitated Aerobic Granular Sludge with Waste Fats |
| title_fullStr | Optimisation of Biogas Production in the Co-Digestion of Pre-Hydrodynamically Cavitated Aerobic Granular Sludge with Waste Fats |
| title_full_unstemmed | Optimisation of Biogas Production in the Co-Digestion of Pre-Hydrodynamically Cavitated Aerobic Granular Sludge with Waste Fats |
| title_short | Optimisation of Biogas Production in the Co-Digestion of Pre-Hydrodynamically Cavitated Aerobic Granular Sludge with Waste Fats |
| title_sort | optimisation of biogas production in the co digestion of pre hydrodynamically cavitated aerobic granular sludge with waste fats |
| topic | anaerobic digestion aerobic granular sludge waste fats co-digestion biogas methane |
| url | https://www.mdpi.com/1996-1073/17/4/922 |
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