澄清器
沉淀
脱水
沉积作用
流出物
曝气泻湖
胞外聚合物
活性污泥
悬浮物
曝气
絮凝作用
污泥膨胀
分段丝状菌
倾析
化学
制浆造纸工业
环境工程
污水处理
色谱法
废水
环境科学
生物膜
沉积物
岩土工程
生物
细菌
地质学
工程类
古生物学
遗传学
有机化学
作者
Allen C. Chao,Thomas M. Keinath
出处
期刊:Water Research
[Elsevier]
日期:1979-01-01
卷期号:13 (12): 1213-1223
被引量:93
标识
DOI:10.1016/0043-1354(79)90165-9
摘要
The separation of microbial mass in an activated sludge system depends on the formation of large settleable sludge flocs. Microbial cells agglomerate into small clumps and subsequently into sludge flocs by a natural bioflocculation process. The resulting biological mass may exist as individual cells, small aggregates, or large flocs in the aeration basin effluent. In the secondary clarifier, only large flocs are separated by sedimentation while individual cells and small aggregates are washed out as effluent suspended solids. In the present study, the separation of sludge by sedimentation was shown to be closely related to the surface roughness of the resulting flocs. Normal sludges were observed to have relatively smooth surfaces while filamentous and zoogloeal bulking sludges were noted to have rough and diffused surfaces. The filamentous growths and the non-filamentous protuberances on the bulking sludge surface serve to increase the frictional drag between the moving solid and the liquid. This contributes to a lower settling velocity and associated dewatering rate of bulking sludges. Conversely, the quantity of non-settleable solids was shown to be related to the quantity of extracellular biopolymers excreted by the microorganisms. The quantity of biopolymers produced decreased for higher Process Loading Intensity or lower sludge age levels thereby resulting in poor aggregation of cells into clumps and subsequently into flocs. This contributes to low clarification efficiencies of the activated sludge process.
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