高盐好氧颗粒污泥的形成过程及机制

Granulation Process and Mechanism of Hypersaline Aerobic Granular Sludge

对SBR反应器中高盐好氧颗粒污泥的形成过程、颗粒粒径分布和形成机制进行了研究。结果表明,不同操作条件下产生了结构、形态不同的颗粒污泥,盐胁迫方式是影响颗粒污泥形态的主要因素,反应器有机负荷和Al3+的添加对颗粒污泥的结构有一定影响,同时有机负荷、水力剪切力和盐胁迫方式是适度诱发丝状菌的有效控制措施。不同反应器中形成的颗粒污泥粒径差异性较大,颗粒的离散度与平均粒径呈正相关。在高盐条件下好氧颗粒污泥的形成是晶核理论、丝状菌理论和胞外聚合物(EPS)理论共同作用的结果。其中,低浓度初始盐胁迫选择压下形成的颗粒污泥较密实,以EPS架桥模型为主,同时存在适量的丝状菌可缠绕连接胶团菌作为絮体的骨架;高浓度初始盐胁迫选择压下形成的颗粒污泥较疏松,周边布满丝状菌菌丝,并呈分散式增长,以丝状菌相互缠绕模型为主。

The granulation process of hypersaline aerobic granular sludge, size distribution of gran- ules and granulation mechanism were investigated in sequencing batch reactors. The results indicated that granular sludge with different morphologies and structures would be formed under different operating conditions. The salt stress mode was a major factor influencing the granular sludge morphology, meanwhile the organic loading rate of the reactor and aluminum ion dosage influenced the granular structure. Fur- thermore, effective control measures such as organic loading rate, hydraulic shear stress and salt stress mode could induce an appropriate growth of filamentous bacteria. High difference in granule size and a positive correlation between the dispersion level and mean size of granules were observed in different reac- tors. The granulation controlled jointly by crystal nucleus, filamentous bacteria and extracellular polymeric substances （EPS） theory was proposed for the growth of hypersaline aerobic granules. Granules under low initial slat stress showed high density, and thus EPS-linking was the main mechanism of granulation. Meanwhile, some existing filamentous bacteria could entangle and link floc-forming bacteria as a frame-work of flocs. In contrast, granules under high initial slat stress showed low density, filamentous bacteria grew dispersedly around, and thus the entanglement of filamentous bacteria was the main mechanism of granulation.