Compression characteristics of alum sludge and pressure loss in the cake under constant rate dewatering

Koki Goto, A. Sato

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The results in this paper are summarized as follows: 1) The properties of a compressive cake can be expressed by the parameter of silica/alumina ratio. 2) From the results of compression-permeability tests, the floc structure in the cake changes rapidly by the slight decrease of porosity in the range of higher porosity than the Liquid Limit, and then the permeability of a cake decreases rapidly. In the range of high compressive pressure, the change of floc structure is small, and therefore the permeability of a cake decreases gently. From these results, it follows that the porosity at the Liquid Limit of alum sludges is the transition point where the floc structure in the cake changes. 3) When the constant rate dewatering is carried out in order to prevent the liquid pressure drop near the medium at the initial dewatering stage, it is possible to obtain about three times larger filtrate under low constant rate dewatering (q = 0.025 cm/min) than under high constant rate dewatering (q = 0.2 cm/min) at the applied pressure 4 kgf/cm2 independently of sludge components. 4) Although the liquid pressure loss of the thin cake layer (0 to 0.5 mm layer from the medium) under high constant rate dewatering (q = 0.2 cm/min) is about 90 to 94% of applied pressure, it becomes at most 56 to 74% under low constant rate dewatering (q = 0.025 cm/min).

Original languageEnglish
Title of host publicationWater Supply
Pages367-376
Number of pages10
Volume4
Edition1
Publication statusPublished - 1986 Jan 1
EventWater Seoul '85, Proc of the 5th Water Supply Conf of the Asian Pac Reg of IWSA - Seoul, S Korea
Duration: 1985 Sep 151985 Sep 21

Other

OtherWater Seoul '85, Proc of the 5th Water Supply Conf of the Asian Pac Reg of IWSA
CitySeoul, S Korea
Period85/9/1585/9/21

ASJC Scopus subject areas

  • Engineering(all)

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    Goto, K., & Sato, A. (1986). Compression characteristics of alum sludge and pressure loss in the cake under constant rate dewatering. In Water Supply (1 ed., Vol. 4, pp. 367-376)