National Taiwan University Dept Chem EngnChung, H.Y.H.Y.ChungJu, S.P.S.P.JuLee, D.J.D.J.Lee2006-11-142018-06-282006-11-142018-06-282003http://ntur.lib.ntu.edu.tw//handle/246246/2006111501275357We hung the activated sludge flocs on an elastic nylon stick and then subjected it to a uniform water flow and measured its displacement. The hydrodynamic drag force exerted on the floc was subsequently estimated, both for cationic flocculated flocs and for flocculated and then frozen/thawed flocs. A confocal laser scanning microscope (CLSM) was employed to probe the interior structure of flocs. Polyelectrolyte flocculation leads to a compact global structure, and hence high drag force exerted on the floc by water. The corresponding CDΩ value at Re = 12–27 for flocs ranges from 1.58 to 3.61. Fast freezing would little affect the hydrodynamic drag force. Slow freezing, in contrast, considerably consolidated the floc structure and hence presented impermeable sphere-like behavior of the slowly frozen/thawed flocs.application/pdf527765 bytesapplication/pdfen-USFloc structureDrag forceActivated sludgeFreezingMeasurement[SDGs]SDG6journal article10.1016/S0021-9797(03)00404-1http://ntur.lib.ntu.edu.tw/bitstream/246246/2006111501275357/1/6801.pdf