Two perturbations were investigated in acidogenic co-fermentation of waste activated sludge (WAS) and food waste in continuous mesophilic fermenters: increasing the organic loading rate (OLR) and changing the WAS. A control reactor maintained an OLR of 11 gVS/(L·d), while a test reactor had a prolonged OLR change to 18 gVS/(L·d). For each OLR, two WAS were studied. The change in OLR led to differentiated fermentation product profile without compromising the fermentation yields (∼300 mgCOD/gVS). At 11 gVS/(L·d), the product profile was dominated by acetic, butyric, and propionic acids while at 18 gVS/(L·d) it shifted to acetic acid, ethanol, and caproic acid. Reverting the OLR also reverted the fermentation profile. The biomass immigration with the WAS changed the fermentation microbial structure and introduced acetic acid-consuming methanogens, which growth was only delayed by the OLR increase. Microbial monitoring and post-fermentation tests can be used for early detection of acetic acid-consuming events.

中文翻译：

---

羧酸生产共发酵中对有机负荷和活性污泥变化的适应能力


研究了连续中温发酵罐中废弃活性污泥 (WAS) 和食品垃圾的产酸共发酵中的两种扰动：增加有机负荷率 (OLR) 和改变 WAS。对照反应堆保持 11 gVS/(L·d) 的 OLR，而测试反应堆的 OLR 变化延长至 18 gVS/(L·d)。对于每个 OLR，研究了两个 WAS。 OLR 的变化导致发酵产物特征差异化，且不影响发酵产量（∼300 mgCOD/gVS）。在 11 gVS/(L·d) 时，产物特征主要是乙酸、丁酸和丙酸，而在 18 gVS/(L·d) 时则转向乙酸、乙醇和己酸。恢复 OLR 也恢复了发酵曲线。 WAS 的生物量迁移改变了发酵微生物结构并引入了消耗乙酸的产甲烷菌，其生长仅因 OLR 的增加而延迟。微生物监测和发酵后测试可用于早期检测乙酸消耗事件。