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Thickening of Sludge from DAF process by Flotation; Application of Solid Flux Theory and Effective Factors  

Park, Sangcheol (서울대학교)
Han, Mooyoung (서울대학교)
Dockko, Seok (단국대학교)
Kwon, Soonbuhm (한국수자원공사)
Publication Information
Journal of Korean Society of Water and Wastewater / v.20, no.4, 2006 , pp. 617-626 More about this Journal
Abstract
Compared with the sludge from gravity sedimentation, it is difficult for operations to settle the sludge occurred from dissolved-air-flotation (DAF). Even though there are some problems in treating DAF sludge with conventional gravity thickeners, those has been used until now. In this study, Solid Flux theory for gravity thickening was applied to the Solid Flux of DAF sludge through flotation in order to develop new methodology for treatment of DAF sludge. Also, characteristics of DAF sludge were investigated. From the experiment results, it was revealed that the higher the polymer dosage, at fixed the solid concentration, the greater the rising velocity becomes. When we applied solid flux theory, the relationship, which is similar to that of gravity thickening, has been achieved. Also, we could find the proper polymer dosage from the rising velocity is about 50 mg/L. Consequently, the limiting solid flux can be derived from the relationship between the total solid flux and the withdrawal velocity of DAF sludge. Furthermore, the factors, such as solid concentrations, bubble volume, pH, zeta potential, and temperature, have effects on the flotation and sedimentation for DAF sludge treatment.
Keywords
Sludge from DAF plant; Solid Flux; Rising velocity; Polymer dosage; Effective factors;
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