Measurement of cell density and floc property of excess activated sludge conditioned by freezing and thawing process, using centrifugal settling.

Unidirectional Freezing of Waste-Activated Sludges: Effects of Freezing Speed

“…For activated sludges, the freezing speed investigated in available literature ranges from 0.6 to 8 µm/s (6,9,(13)(14)(15)(16), or 11 µm/s (24). Most of these experimental results are thus typical of type II floc characteristics.…”

Fast Freeze/Thaw Treatment on Excess Activated Sludges: Floc Structure and Sludge Dewaterability

“…Freeze/thaw processes have been investigated extensively (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25). It is found that this physical process can significantly improve certain sludge dewatering characteristics and change the floe structure, usually irreversibly, into a more compact form (e.g.,seeref25).…”

“…It is found that this physical process can significantly improve certain sludge dewatering characteristics and change the floe structure, usually irreversibly, into a more compact form (e.g.,seeref25). Thesuspended particles tend to agglomerate and form larger floes within which the bound water content is reduced (17)(18)(19)(20)(21).…”

High-level deliquoring of activated sludge by ultrahigh-pressure expression combined with flocculation

“…11, w 1 /w d is plotted against the reciprocal expression pressure (1/p c ), where w 1 is the final wet cake mass per unit crosssectional area, corresponding the expression pressure, and w d is the dry cake mass per unit cross-sectional area (Nakakura et al, 1996). The final wet cake mass at the infinite pressure, which is related to the amount of the bound water, has been frequently evaluated from the ordinate intercept of the straight line of experimental data (Kawasaki et al, 1990a;Matsuda et al, 1992). However, the plots deviate from a linear relationship at more than 2 MPa pressures, and thus it is essential to measure the moisture content of the compressed cake from the real experiments in order to obtain the cake moisture content attained by ultrahigh pressure expression.…”