Theories of cake filtration and consolidation and implications to sludge dewatering

This work presents a mini-review of the various theories in previous literature while considering the transport processes in filter cakes during filtration and consolidation. The development of the conventional two-resistance theory (referred to herein as conventional theory) is initially discussed based on different types of power-law constitutive equations. Multi-phase theory is then described, along with the criticisms raised by Willis et al. over the past two decades. Also discussed herein is the validity of some frequently adopted assumptions in filtration studies. Implications of the filtration/consolidation theory to sludge dewatering are finally made.