The effect of global velocity gradient on the character and filterability of aggregates formed during the coagulation/flocculation process

0360835 - ÚH 2012 RIV GB eng J - Journal Article
Pivokonský, Martin - Bubáková, Petra - Pivokonská, Lenka - Hnaťuková, Petra
The effect of global velocity gradient on the character and filterability of aggregates formed during the coagulation/flocculation process.
Environmental Technology. Roč. 32, č. 12 (2011), s. 1355-1366. ISSN 0959-3330. E-ISSN 1479-487X
R&D Projects: GA AV ČR IAA200600902
Institutional research plan: CEZ:AV0Z20600510
Keywords : aggregate size distribution * flocculation * mixing * fractal dimension * filtration
Subject RIV: BK - Fluid Dynamics
Impact factor: 1.406, year: 2011

Paper describes the influence of the global velocity gradient G on the properties of aggregates formed during the coagulation/flocculation process. The methods of image and fractal analysis were used to determine aggregate size and structure, respectively. The influence of these aggregate properties on separation using depth filtration is also described. The suspension was formed in a flow mixing tank with global velocity gradients ranging from 28.4–307.2 s⁻¹ and ferric sulphate used as a coagulant. Predictably, it was shown that the aggregate size decreased with increasing global velocity gradient G. Furthermore it was demonstrated that, with increasing G, the aggregates became more compact and regular and the suspension became more homogeneous in size. The aggregates with the smallest diameter and highest fractal dimension displayed the best filterability, i.e. penetrated throughout the full depth of the filter bed and generated a minimum pressure drop.
Permanent Link: http://hdl.handle.net/11104/0198291