This study investigated the impact of two low-temperature thermal pre-treatments on continuous anaerobic reactors’ performance, sequentially fed with sludge of different total solids content (∼3 % and ∼6 %) and subjected to progressively increasing Organic Loading Rates (OLR) from 1.0 to 2.5 g volatile solids/(L⋅day). Assessing pre-treatments’ influence on influent sludge characteristics revealed enhanced organic matter hydrolysis, facilitating sludge solubilization and methanogenesis; volatile fatty acids concentration also increased, particularly in pre-treated sludge of ∼6 % total solids, indicating improved heating efficiency under increased solids content. The reactor fed with sludge pre-treated at 45 °C for 48 h and 55 °C for an extra 48 h exhibited the highest methane yield under all applied OLRs, peaking at 240 ± 3.0 mL/g volatile solids at the OLR of 2.5 g volatile solids/(L⋅day). 16S rRNA gene sequencing demonstrated differences in the reactors’ microbiomes as evidence of sludge thickening and the different pre-treatments applied, which promoted the release of organic matter in diverse concentrations and compositions. Finally, the microbial analysis revealed that specific foam-related genera increased in abundance in the foam layer of reactors’ effluent bottles, dictating their association with the sludge foaming incidents that occurred inside the reactors during their operation at 2.0 g volatile solids/(L⋅day).

中文翻译：

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通过连续反应器运行评估最佳污水污泥预处理技术：工艺性能和微生物群落见解

本研究研究了两种低温热预处理对连续厌氧反应器性能的影响，依次喂入不同总固体含量（∼3%和∼6%）的污泥，并逐渐增加有机负荷率（OLR） 1.0 至 2.5 克挥发性固体/(L·天)。评估预处理对进水污泥特性的影响表明，有机物水解增强，促进污泥溶解和产甲烷；挥发性脂肪酸浓度也增加，特别是在总固体含量约为 6% 的预处理污泥中，表明在固体含量增加的情况下加热效率提高。在所有应用的 OLR 下，喂入在 45 °C 预处理 48 小时和 55 °C 预处理 48 小时的污泥的反应器表现出最高的甲烷产率，在 OLR 为 2.5 g 时峰值为 240 ± 3.0 mL/g 挥发性固体挥发性固体/(L·天)。 16S rRNA 基因测序证明了反应器微生物组的差异，作为污泥增稠和应用的不同预处理的证据，这促进了不同浓度和成分的有机物的释放。最后，微生物分析表明，反应器流出瓶的泡沫层中与特定泡沫相关的属大量增加，表明它们与反应器在 2.0 g 挥发性固体/(L⋅天）。