Acidogenic co-fermentation of waste activated sludge (WAS) and food waste (FW) under thermophilic conditions enhances process consistency, while overcoming the problem of acetic acid consumption by growing methanogens. Two long-term continuous co-fermentation experiments were carried out with a WAS:FW mixture (70:30 % in VS) at organic loading rate of 8 gVS/(L·d). Experiment 1 assessed the impact of temperature (35°C and 55°C) and the WAS origin (WAS_A and WAS_B) in two collection periods. Experiment 2 evaluated the consistency at 55°C by testing three WAS origins (WAS_A, WAS_B and WAS_C) in 3 additional collection periods. Experimental results showed that at 55°C, the solubilisation yield was enhanced compared to 35°C, although this did not always lead to higher fermentation yield. The fermentation product profile was affected by the operating temperature, with 55 °C promoting the accumulation of acetic and butyric acids. Acetic acid consumption was only detected at 35°C in fermenters treating WAS_A, whereas it was not observed in fermenters treating WAS_B. This consumption was prevented at 55 °C, as none of the 13 fermenters continuous operation showed acetic acid consumption. Acetic acid consumption was attributed to species midas_s_9557 (genus Methanosarcina), an aceticlastic methanogen, which did not grow under 55°C. Temperature had a more significant effect on the microbial community than the WAS origin. Functional redundancy was demonstrated by each fermenter having its own distinct microbial consortium while maintaining constant metabolic functions at 55°C. Overall, the acidogenic co-fermentation of WAS and FW at 55 °C is regarded as a robust and consistent biotechnology.

中文翻译：

---

在嗜热条件下，废弃活性污泥和食物垃圾进行一致的产酸共发酵


在嗜热条件下，废弃活性污泥 （WAS） 和食物垃圾 （FW） 的产酸共发酵提高了工艺一致性，同时克服了生长产甲烷菌消耗乙酸的问题。使用 WAS：FW 混合物（VS 中 70：30%）以 8 gVS/（L·d） 的有机负荷率进行了两次长期连续共发酵实验。实验 1 评估了温度 （35°C 和 55°C） 和 WAS 来源 （WAS_A 和 WAS_B） 在两个收集期的影响。实验 2 通过在 3 个额外的收集期中测试三个 WAS 来源 （WAS_A、WAS_B 和 WAS_C） 来评估 55°C 下的一致性。实验结果表明，在 55°C 时，增溶率比 35°C 更高，尽管这并不总是导致更高的发酵产量。发酵产物谱受工作温度的影响，55 °C 促进乙酸和丁酸的积累。在处理WAS_A的发酵罐中，仅在 35°C 时检测到乙酸消耗量，而在处理WAS_B的发酵罐中未观察到。在 55 °C 时可以防止这种消耗，因为 13 个发酵罐连续运行中没有一个显示乙酸消耗。乙酸消耗归因于物种 midas_s_9557（属 Methanosarcina），一种醋酸碎屑产甲烷菌，在 55°C 下不生长。 温度对微生物群落的影响比 WAS 起源更显着。每个发酵罐都有自己独特的微生物群落，同时在 55°C 下保持恒定的代谢功能，从而证明了功能冗余。 总体而言，WAS 和 FW 在 55 °C 下的产酸共发酵被认为是一种稳健且一致的生物技术。