Publicação
Optimizing biogas production via ozone sludge pretreatment
| Resumo: | Anaerobic digestion (AD) is the preferred method for handling wastewater sludge while producing renewable energy in the form of biogas. However, this process often occurs during the hydrolysis phase, which can prevent the system from working at maximum efficiency. This study examined the effect of ozone pre-treatment on methane generation from municipal sludge during mesophilic batch digestion. Ozone was applied at concentrations of 0%, 5%, and 10% for exposure times of 30, 60, and 90 s, respectively. A series of anaerobic co-digestion experiments was then conducted using different inoculum-tosubstrate (I/S) ratios of 1.0, 1.5, and 2.0. Methane production was continuously monitored using the AMPTS II system. The methane yield was 736 NmL CH4 g-1 VS at an ozone concentration of 4.41 L min-1. The Buswell–Mueller equation was applied to estimate the theoretical biochemical methane potential (TBMP), resulting in a value of approximately 517 mL CH₄ per gram of volatile solids (VS). Kinetic modeling using the modified Gompertz equation showed faster methane production rates and reduced lag times under the optimized pretreatment conditions. Overall, the data suggest that ozone pretreatment, when carefully controlled, can significantly improve sludge biodegradability and enhance biogas yields, indicating a promising method for increasing energy recovery in wastewater treatment systems. Furthermore, a comparative evaluation of four kinetic models (Gompertz, Logistic, Transference, and Cone) was conducted to identify the most suitable approach for describing biogas production kinetics under ozone pretreatment. Although all models provided statistically robust fits, the Logistic and Gompertz models demonstrated slightly superior consistency and interpretability across the range of experimental conditions. This careful model selection not only improved the reliability of methane yield predictions but also supported more informed process optimization. Overall, these findings emphasize that integrating robust kinetic modeling with innovative pretreatment strategies can significantly enhance biogas yield and process efficiency, offering valuable insights into advancing sustainable energy recovery from municipal sludge. |
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| Autores principais: | Alqudah, Safaa Ahmad Mustafa |
| Assunto: | Anaerobic digestion Biogas production Co-digestion Gompertz model Methane yield Ozone pretreatment Sludge solubilization Wastewater sludge |
| Ano: | 2025 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Instituto Politécnico de Bragança |
| Idioma: | inglês |
| Origem: | Biblioteca Digital do IPB |
| Resumo: | Anaerobic digestion (AD) is the preferred method for handling wastewater sludge while producing renewable energy in the form of biogas. However, this process often occurs during the hydrolysis phase, which can prevent the system from working at maximum efficiency. This study examined the effect of ozone pre-treatment on methane generation from municipal sludge during mesophilic batch digestion. Ozone was applied at concentrations of 0%, 5%, and 10% for exposure times of 30, 60, and 90 s, respectively. A series of anaerobic co-digestion experiments was then conducted using different inoculum-tosubstrate (I/S) ratios of 1.0, 1.5, and 2.0. Methane production was continuously monitored using the AMPTS II system. The methane yield was 736 NmL CH4 g-1 VS at an ozone concentration of 4.41 L min-1. The Buswell–Mueller equation was applied to estimate the theoretical biochemical methane potential (TBMP), resulting in a value of approximately 517 mL CH₄ per gram of volatile solids (VS). Kinetic modeling using the modified Gompertz equation showed faster methane production rates and reduced lag times under the optimized pretreatment conditions. Overall, the data suggest that ozone pretreatment, when carefully controlled, can significantly improve sludge biodegradability and enhance biogas yields, indicating a promising method for increasing energy recovery in wastewater treatment systems. Furthermore, a comparative evaluation of four kinetic models (Gompertz, Logistic, Transference, and Cone) was conducted to identify the most suitable approach for describing biogas production kinetics under ozone pretreatment. Although all models provided statistically robust fits, the Logistic and Gompertz models demonstrated slightly superior consistency and interpretability across the range of experimental conditions. This careful model selection not only improved the reliability of methane yield predictions but also supported more informed process optimization. Overall, these findings emphasize that integrating robust kinetic modeling with innovative pretreatment strategies can significantly enhance biogas yield and process efficiency, offering valuable insights into advancing sustainable energy recovery from municipal sludge. |
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