Hydrothermal Carbonization of Dry Anaerobic Digestion Residues Derived from Food and Agro Wastes in Lesvos Island
Biowaste management is at the center of attention in recent years due to the increased focus on Circular Economy practices. Lesvos has numerous food processing facilities and olive mills, and therefore Olive Mill Wastewater (OMWW) is a wastewater stream that requires attention. In this study, a holi...
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MDPI AG
2023-06-01
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| Series: | Energies |
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| Online Access: | https://www.mdpi.com/1996-1073/16/12/4619 |
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| author | Panagiotis Xypolias Stergios Vakalis Ioannis Daskaloudis Dimitrios Francis Lekkas |
| author_facet | Panagiotis Xypolias Stergios Vakalis Ioannis Daskaloudis Dimitrios Francis Lekkas |
| author_sort | Panagiotis Xypolias |
| collection | DOAJ |
| description | Biowaste management is at the center of attention in recent years due to the increased focus on Circular Economy practices. Lesvos has numerous food processing facilities and olive mills, and therefore Olive Mill Wastewater (OMWW) is a wastewater stream that requires attention. In this study, a holistic experimental set-up that combines aerobic and anaerobic treatment strategies was developed taking into consideration the hydrothermal carbonization of AD digestate along with locally available OMWW. The study focuses on the hydrothermal carbonization (HTC) of anaerobic residues from biogas production, and food waste was co-utilized with spent coffee grounds (SCG). The reduced volatile solids of SCG have some effects on the final products. AD produced methane yields of 54.7% for the food waste and 52.4%. for the feedstock with added SCG. At the same time, the feedstock that contained SCG produced more hydrochar that reached up to 50% of the yield. Hydrothermal carbonization in a water medium produced liquids with basic pH values around 8 and conductivities of 4–5 mS/cm, while the samples that were treated in OMWW medium had pH values close to 5.5 and conductivities of around 12 mS/cm. The produced hydrochars have significant calorific values that exceeded 20 MJ/kg for almost all the samples. Overall, HTC with OMWW as a medium was able significantly reduce the COD of OMWW while resulting in hydrochars with increased heating values. |
| first_indexed | 2024-03-11T02:32:09Z |
| format | Article |
| id | doaj.art-d8e073dd7d37494e9e152c478eaec957 |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-03-11T02:32:09Z |
| publishDate | 2023-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-d8e073dd7d37494e9e152c478eaec9572023-11-18T10:11:51ZengMDPI AGEnergies1996-10732023-06-011612461910.3390/en16124619Hydrothermal Carbonization of Dry Anaerobic Digestion Residues Derived from Food and Agro Wastes in Lesvos IslandPanagiotis Xypolias0Stergios Vakalis1Ioannis Daskaloudis2Dimitrios Francis Lekkas3Waste Management Laboratory, Department of Environment, University of the Aegean, University Hill, 81100 Mytilene, GreeceEnergy Management Laboratory, Department of Environment, University of the Aegean, University Hill, 81100 Mytilene, GreeceWaste Management Laboratory, Department of Environment, University of the Aegean, University Hill, 81100 Mytilene, GreeceWaste Management Laboratory, Department of Environment, University of the Aegean, University Hill, 81100 Mytilene, GreeceBiowaste management is at the center of attention in recent years due to the increased focus on Circular Economy practices. Lesvos has numerous food processing facilities and olive mills, and therefore Olive Mill Wastewater (OMWW) is a wastewater stream that requires attention. In this study, a holistic experimental set-up that combines aerobic and anaerobic treatment strategies was developed taking into consideration the hydrothermal carbonization of AD digestate along with locally available OMWW. The study focuses on the hydrothermal carbonization (HTC) of anaerobic residues from biogas production, and food waste was co-utilized with spent coffee grounds (SCG). The reduced volatile solids of SCG have some effects on the final products. AD produced methane yields of 54.7% for the food waste and 52.4%. for the feedstock with added SCG. At the same time, the feedstock that contained SCG produced more hydrochar that reached up to 50% of the yield. Hydrothermal carbonization in a water medium produced liquids with basic pH values around 8 and conductivities of 4–5 mS/cm, while the samples that were treated in OMWW medium had pH values close to 5.5 and conductivities of around 12 mS/cm. The produced hydrochars have significant calorific values that exceeded 20 MJ/kg for almost all the samples. Overall, HTC with OMWW as a medium was able significantly reduce the COD of OMWW while resulting in hydrochars with increased heating values.https://www.mdpi.com/1996-1073/16/12/4619food wastehydrothermal carbonizationhydrocharbiowasteanaerobic digestion |
| spellingShingle | Panagiotis Xypolias Stergios Vakalis Ioannis Daskaloudis Dimitrios Francis Lekkas Hydrothermal Carbonization of Dry Anaerobic Digestion Residues Derived from Food and Agro Wastes in Lesvos Island Energies food waste hydrothermal carbonization hydrochar biowaste anaerobic digestion |
| title | Hydrothermal Carbonization of Dry Anaerobic Digestion Residues Derived from Food and Agro Wastes in Lesvos Island |
| title_full | Hydrothermal Carbonization of Dry Anaerobic Digestion Residues Derived from Food and Agro Wastes in Lesvos Island |
| title_fullStr | Hydrothermal Carbonization of Dry Anaerobic Digestion Residues Derived from Food and Agro Wastes in Lesvos Island |
| title_full_unstemmed | Hydrothermal Carbonization of Dry Anaerobic Digestion Residues Derived from Food and Agro Wastes in Lesvos Island |
| title_short | Hydrothermal Carbonization of Dry Anaerobic Digestion Residues Derived from Food and Agro Wastes in Lesvos Island |
| title_sort | hydrothermal carbonization of dry anaerobic digestion residues derived from food and agro wastes in lesvos island |
| topic | food waste hydrothermal carbonization hydrochar biowaste anaerobic digestion |
| url | https://www.mdpi.com/1996-1073/16/12/4619 |
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