Thiothrix eikelboomii interferes oxygen transfer in activated sludge.
Thiothrix eikelboomii interferes oxygen transfer in activated sludge.
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DOI：
10.1016/j.watres.2018.12.019
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发表时间：
2019-03
期刊：
影响因子：
12.8
通讯作者：
Xianwei Wu;Ju-chang Huang;Zichuan Lu;Gaofeng Chen;Jianmin Wang;Guoqiang Liu
中科院分区：
文献类型：
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作者：
Xianwei Wu;Ju-chang Huang;Zichuan Lu;Gaofeng Chen;Jianmin Wang;Guoqiang Liu
本研究发现，引起污泥膨胀的丝状细菌thiiothrix eikelboomii也会干扰废水处理过程中的氧传递。在相同生物质浓度下，丝状膨胀污泥（FBS）的体积氧传递系数（KLa）比絮凝形成污泥（FFS）低43%，部分原因是丝状菌增加了污泥的表观粘度。然而，即使两种污泥的表观粘度相似，FBS的KLa值仍显著低于FFS。气泡表面附着了许多细小且自由游动的细丝，这可能减少了液膜的更新，增加了液膜的厚度。此外，这些纤维还被细胞外蛋白质和多糖的聚合物质共包覆，使其具有表面活性剂的“两亲分子”作用，阻碍氧的转移。因此，细丝的特殊表面性质及其与气泡的相互作用也会影响氧的传递。结果表明，Thiothrix eikelboomi是降低KLa值的丝状细菌，而其他短丝丝状细菌对氧传递没有干扰。研究表明，控制污泥膨胀不仅有利于污泥沉降，而且有利于氧转移。
This study revealed that,Thiothrix eikelboomii, a well-known filamentous bacterium that causes sludge bulking, could also interfere oxygen transfer during wastewater treatment. The volumetric oxygen transfer coefficient (KLa) in filamentous-bulking sludge (FBS) was found to be 43% lower than that in floc-forming sludge (FFS) at similar biomass concentrations, partially because the filamentous bacteria had increased the sludge apparent viscosity. The KLa value for FBS, however, was still significantly lower than that for FFS even if both sludges had similar apparent viscosity. Numerous tiny and free-swimming filaments were observed to attach on the air bubble surface, presumably reducing the liquid film renewal and increasing the liquid film thickness. Moreover, the filaments were co-coated with extracellular polymeric substances of protein and polysaccharide, which could make them performing like “amphiphilic molecules” of surfactants to hinder oxygen transfer. Therefore, the particular surface property of filaments and their interaction with air bubbles could also impact oxygen transfer.Thiothrix eikelboomiiwas identified to be the responsible filamentous bacterium that lowered the KLa value, while other filamentous bacteria with short filaments did not interfere oxygen transfer. This study implies that controlling sludge bulking benefits not only sludge settling but also oxygen transfer.