Sludge disposal is a key issue in wastewater treatment facilities and, therefore, represents an important factor for economical management of municipal sewage plants. On the other hand, efficient anaerobic digestion does not only represent a suitable solution for sludge disposal, but also provides additional energy gain from biogas use in cogeneration. In this study, a significant improvement in sludge treatment and energy recovery by an innovative two-phase anaerobic digestion process is reported. The main feature of this new process is CO2 use and conversion to organic carbon during a hydrolytic-acidogenic-acetogenic fermentation step. A demonstration run was carried out in a versatile 2.7 mc pilot plant located within the municipal wastewater treatment plant of the city of Bologna (Italy). By means of an appropriate conditioning of WWT sludge, highly selected microbial cultures could be obtained and maintained, to perform a two-phase anaerobic digestion process. In particular, acid conditions were established in the first reactor (DIG2) by hydrolytic, acidogenic and acetogenic bacteria in presence of carbon dioxide flux, at moderate pressure and mesophilic temperature. Methanogenic conditions were developed in the second reactor (DIG3). As expected from the two-phase configuration, biogas production was carried out in DIG3, while significant carbon dioxide absorption was detected in DIG2. A steady-state, two-phase anaerobic process was successfully operated throughout the whole demonstration period. Volatile suspended solid (VSS) reduction in the pilot plant was 58%, which was significantly better than that of the main facility. At the same time, the reported methane productivity is much higher than the one of the main facility. In conclusion, the aforementioned process configuration can enhance solid reduction, boosting methane production and performing an improved greenhouse gas (GHG) balance for anaerobic digestion. Different process configurations are under study to answer specific requirements, such as improved CO2 conversion, industrial waste disposal and maximized biogas productivity
Enhanced biosolid reduction and conversion to methane by CO2 injection in a two-Phase anaerobic digestion pilot plant / Salomoni C. ; Caputo A.; Bonoli M.; Francioso O.; Rodriguez-Estrada M.T.; Palenzona D.. - STAMPA. - (2010), pp. 1-8. (Intervento presentato al convegno ECSM 2010-2nd European Conference on Sludge Management tenutosi a Budapest, Hungary, nel 9-10 September 2010).
Enhanced biosolid reduction and conversion to methane by CO2 injection in a two-Phase anaerobic digestion pilot plant
FRANCIOSO, ORNELLA;RODRIGUEZ ESTRADA, MARIA TERESA;PALENZONA, DOMENICO
2010
Abstract
Sludge disposal is a key issue in wastewater treatment facilities and, therefore, represents an important factor for economical management of municipal sewage plants. On the other hand, efficient anaerobic digestion does not only represent a suitable solution for sludge disposal, but also provides additional energy gain from biogas use in cogeneration. In this study, a significant improvement in sludge treatment and energy recovery by an innovative two-phase anaerobic digestion process is reported. The main feature of this new process is CO2 use and conversion to organic carbon during a hydrolytic-acidogenic-acetogenic fermentation step. A demonstration run was carried out in a versatile 2.7 mc pilot plant located within the municipal wastewater treatment plant of the city of Bologna (Italy). By means of an appropriate conditioning of WWT sludge, highly selected microbial cultures could be obtained and maintained, to perform a two-phase anaerobic digestion process. In particular, acid conditions were established in the first reactor (DIG2) by hydrolytic, acidogenic and acetogenic bacteria in presence of carbon dioxide flux, at moderate pressure and mesophilic temperature. Methanogenic conditions were developed in the second reactor (DIG3). As expected from the two-phase configuration, biogas production was carried out in DIG3, while significant carbon dioxide absorption was detected in DIG2. A steady-state, two-phase anaerobic process was successfully operated throughout the whole demonstration period. Volatile suspended solid (VSS) reduction in the pilot plant was 58%, which was significantly better than that of the main facility. At the same time, the reported methane productivity is much higher than the one of the main facility. In conclusion, the aforementioned process configuration can enhance solid reduction, boosting methane production and performing an improved greenhouse gas (GHG) balance for anaerobic digestion. Different process configurations are under study to answer specific requirements, such as improved CO2 conversion, industrial waste disposal and maximized biogas productivityI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
