A two-stage process consisting of a pre-acidification unit and an Upflow Anaerobic Sludge Blanket (UASB) reactor (UASBT-S) was compared with a one-stage UASB reactor (UASBO-S) to evaluate the treatment stability of starch wastewater (SW). The Two-stage process provided higher treatment stability than UASBO-S. Sludge floatation occurred in the UASBO-S when the organic loading rate (OLR) was increased to 4 g-COD/L/d, beyond which a paste-like membrane structure adhered to the granules was observed. Further analysis suggests that the substrate derived polysaccharide components embedded in the loosely-bound extracellular polymeric substances (LB-EPS), triggered significant increase in the protein/polysaccharide ratio in the tightly-bound EPS (TB-EPS), and was suggested to result in the granules floatation and disintegration. During the pre-acidification, the starch was mainly converted to acetic and propionic acids. The pre-acidification was beneficial for reducing the EPS content fluctuations in the UASBT-S, which greatly improved settling capability and strength of the granular sludge.

中文翻译：

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预酸化极大地改善了处理低强度淀粉废水的上流厌氧污泥毯子（UASB）反应器的颗粒理化性能和运行稳定性。

比较了一个由预酸化装置和一个上流厌氧污泥床（UASB）反应器（UASBT-S）组成的两步​​法与一个阶段UASB反应器（UASBO-S）来评估淀粉废水的处理稳定性（ SW）。两步工艺比UASBO-S提供更高的处理稳定性。当有机负荷率（OLR）增加到4 g-COD / L / d时，UASBO-S中发生了污泥浮选，超过此值则观察到糊状的膜结构粘附在颗粒上。进一步的分析表明，底物衍生的多糖成分嵌入松散结合的细胞外聚合物（LB-EPS）中，引发了紧密结合的EPS（TB-EPS）中蛋白质/多糖比的显着增加，并建议导致在颗粒中漂浮和崩解。在预酸化过程中，淀粉主要转化为乙酸和丙酸。预酸化有利于减少UASBT-S中EPS含量的波动，从而大大提高了颗粒污泥的沉降能力和强度。