Paulinetti Ana Paula, Guerieri Fernanda Furtunato, Augusto Isabela Mehi Gaspari, Lazaro Carolina Zampol, Albanez Roberta, Lovato Giovanna, Ratusznei Suzana Maria, Domingues Rodrigues José Alberto
Department of Chemical Engineering, Mauá School of Engineering, Mauá Institute of Technology, Praça Mauá 1, Zip Code 09.580-900, São Caetano do Sul/SP, Brazil; Department of Environmental Engineering Sciences, School of Engineering of São Carlos, University of São Paulo, Av. Trabalhador São-Carlense, 400 - Zip Code 13.566-590, São Carlos/SP, Brazil.
Department of Chemical Engineering, Mauá School of Engineering, Mauá Institute of Technology, Praça Mauá 1, Zip Code 09.580-900, São Caetano do Sul/SP, Brazil.
J Environ Manage. 2024 Nov;370:122508. doi: 10.1016/j.jenvman.2024.122508. Epub 2024 Oct 3.
One of the factors that has a direct impact on anaerobic digestion is the applied organic loading rate (OLR). Increasing OLR can boost methane production but can also cause process failure. As a result, establishing the appropriate OLR for the procedure is critical. This study evaluated the effect of increasing the OLR 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 OLR from 10 to 15 and 20 kg-COD/m³/d led to a decrease in COD removal efficiency (90, 86, and 75%), methane yield (12.0, 11.6, and 9.9 mol-CH/kg-COD) and an increase in total volatile acids concentration (251, 456, and 1393 mg-HAc/L, respectively). At 15 kg-COD/m³/d, R-Meso performed similarly to R-Thermo, and at 20 kg-COD/m/d, R-Meso outperformed (81% COD removal efficiency, 9.3 mol-CH/kg-COD and 154.5 mol-CH/m/d). Temperature greatly influenced the distribution of metabolic pathways, as shown by thermodynamic and kinetic analyses, thus impacting bacterial diversity. At 55 °C, amongst the bacterial genera, Tepidiphilus stood out (>28.2%), followed by Acetomicrobium, Coprothermobacter and Candidatus_Caldatribacterium. The OLR 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.
对厌氧消化有直接影响的因素之一是所应用的有机负荷率（OLR）。提高OLR可以促进甲烷的产生，但也可能导致工艺失败。因此，为该工艺确定合适的OLR至关重要。本研究评估了在嗜热厌氧反应器（R-Thermo）中使用大豆糖蜜提高OLR的效果，以及进料策略和与豆渣共处理的效果。此外，还研究了R-Thermo与中温厌氧消化（R-Meso）之间性能与稳定性的权衡。OLR从10增加到15和20 kg-COD/m³/d导致化学需氧量（COD）去除效率降低（分别为90%、86%和75%），甲烷产量降低（分别为12.0、11.6和9.9 mol-CH/kg-COD），总挥发性酸浓度增加（分别为251、456和1393 mg-HAc/L）。在15 kg-COD/m³/d时，R-Meso的表现与R-Thermo相似，在20 kg-COD/m³/d时，R-Meso表现更优（COD去除效率为81%，甲烷产量为9.3 mol-CH/kg-COD，甲烷产率为154.5 mol-CH/m³/d）。热力学和动力学分析表明，温度对代谢途径的分布有很大影响，从而影响细菌多样性。在55°C时，在细菌属中，嗜热栖热菌最为突出（>28.2%），其次是醋微菌属、嗜热栖热杆菌属和热原体属。OLR明显影响古菌群落；嗜热栖热杆菌属（77.4%）比甲烷八叠球菌属（14.8%）更占优势。在嗜热温度下，互营乙酸氧化（SAO）细菌似乎可能与乙酸裂解产甲烷菌竞争底物，而在R-Meso中，负责有机物分解初始步骤的微生物，如厚壁菌门和变形菌门的成员（至少67%）占主导地位。总之，R-Meso的特点是代谢途径分布更均匀，以及微生物群落多样且适应性良好，在高负荷下表现出更高的稳定性，优于R-Thermo。
