Thermophilic and mesophilic anaerobic digestion of soybean molasses: A performance vs. stability trade-off

Autor(es)

Paulinetti, Ana Paula ; Guerieri, Fernanda Furtunato ; Augusto, Isabela Mehi Gaspari ; Lazaro, Carolina Zampol ; Albanez, Roberta ; Lovato, Giovanna ; Ratusznei, Suzana Maria ; Rodriguesa, Jose Alberto Domingues

• Tipo de documento: Artigo Científico
• Fonte: Journal of Environmental Management; v. 370, p. 14-pg., 2024-10-03.

Resumo

One of the factors that has a direct impact on anaerobic digestion is the applied organic loading rate (OLRA). Increasing OLRA can boost methane production but can also cause process failure. As a result, establishing the appropriate OLRA for the procedure is critical. This study evaluated the effect of increasing the OLRA using soybean molasses in a thermophilic anaerobic reactor (R-Thermo), as well as the effect of feeding strategy and co-processing with okara. Furthermore, the performance versus stability trade-off between R-Thermo and mesophilic anaerobic digestion (R-Meso) was investigated. The increase of OLRA from 10 to 15 and 20 kg-COD/m(3)/d led to a decrease in COD removal efficiency (90, 86, and 75%), methane yield (12.0, 11.6, and 9.9 mol-CH4/kg-COD) and an increase in total volatile acids concentration (251, 456, and 1393 mg-HAc/L, respectively). At 15 kg-COD/m(3)/d, R-Meso performed similarly to R-Thermo, and at 20 kg-COD/m(3)/d, R-Meso outperformed (81% COD removal efficiency, 9.3 mol-CH4/kg-CODrem and 154.5 mol-CH4/m(3)/d). Temperature greatly influenced the distribution of metabolic pathways, as shown by thermodynamic and kinetic analyses, thus impacting bacterial diversity. At 55 degrees C, amongst the bacterial genera, Tepidiphilus stood out (>28.2%), followed by Acetomicrobium, Coprothermobacter and Candidatus_Caldatribacterium. The OLRA clearly impacted the archaeal community; Methanothermobacter (77.4%) was favored over Methanosarcina (14.8%). Under thermophilic temperature, it seems that syntrophic acetate oxidation (SAO) bacteria might have competed for substrate with acetoclastic methanogens, while in R-Meso microorganisms responsible for the initial steps of organic matter breakdown, such as members of the Firmicutes and Proteobacteria phyla (at least 67%), were dominant. In summary, R-Meso, characterized by a more uniform distribution of metabolic pathways, as well as a diverse and well-adapted microbial consortium, have exhibited enhanced stability and outperformed R-Thermo at high-loads. (AU)

• Processo FAPESP: 22/01425-4 - Produção de hidrogênio e metano em dois estágios pelo tratamento de resíduos do processamento da soja (melaço e okara) em condição termofílica e mesofílica
• Beneficiário: Isabela Mehi Gaspari Augusto
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto
• Processo FAPESP: 22/05522-4 - Viabilidade operacional de um AnSBBR no tratamento de esgoto sanitário: remoção de diclofenaco e ibuprofeno
• Beneficiário: Ana Paula Paoli
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 22/10615-1 - Consolidação do conceito de biorrefinaria aplicado ao tratamento biológico de águas residuárias e de resíduos sólidos
• Beneficiário: Marcelo Zaiat
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 21/13810-7 - Produção de biocombustíveis pelo tratamento anaeróbio de melaço de soja em condições mesofílica e termofílica
• Beneficiário: Giovanna Lovato
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 21/13797-0 - Produção de metano em AnSBBR termofílico pelo tratamento de melaço de soja
• Beneficiário: Fernanda Furtunato Guerieri
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica