title: Compression and swelling of activated sludge cakes during dewatering.
abstract: A drainage/filtration apparatus was developed for automatically determining sedimentation velocity and dewatering rate. Pressure-step testing was used to study filter cake compressibility, resistance, and swelling. Activated sludge was analysed, and the data indicate that the sludge is highly compressible even at low pressures (10 kPa). Furthermore, compressed sludge cakes swell if the pressure is released. Hence, the average specific cake resistance decreases if the pressure is released, though the resistance is higher after the compression cycle than before. Sludge must be dewatered under low pressure, because higher pressure only compresses the cake and does not improve the dewatering rate.
authors: Department of Biotechnology, Aalborg University, Sohngaardsholmvej 57, 9000 Aalborg, Denmark.
authors: Steffen Gralert
authors: SG
authors: Sveegaard
authors: Kristian
authors: K
authors: Keiding
authors: Morten Lykkegaard
authors: ML
authors: Christensen
mesh_terms: D003890:Desiccation / Q000379:methods*; D005374:Filtration / Q000295:instrumentation / Q000379:methods*; D019793:Fluorescein; D011312:Pressure; D012722:Sewage / Q000737:chemistry*; D014618:Vacuum; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*; D014867:Water / Q000737:chemistry
chemical_list: D012722:Sewage; D014867:Water; D019793:Fluorescein