Use of MF and UF membranes for reclamation of glass industry wastewater containing colloidal clay and glass particles

Microfiltration (MF) or ultrafiltration (UF) can be a viable option for the separation of fine clay and glass particles in glass industry wastewater in order to recycle treated water (permeate) into the manufacturing process. The characteristics of treated water quality and membrane permeability were investigated using MF/UF equipment with different geometry and pore sizes at various operating conditions. Substantial particle removal was accomplished with the membranes having a pore size of less than 0.45 mum and so the quality of permeate was able to satisfy the requirements for reuse. During stirred flow and crossflow filtration runs, shear did have different effects on membrane permeability, which shed new light on an important issue that one result may not be extrapolated from the other. These phenomena could be attributed to the irreversibility of deposited particles with sticky nature as well as the difference of operational modes during MF/UF. To control irrecoverable losses of filterability due to colloidal particle deposition at the membrane surface, severe turbulent flow was required at the commencement of membrane operations. Particles' movement over the membrane surface could be explained based on the distribution of their backtransport velocities at different shear conditions during crossflow filtration. (C) 2003 Elsevier B.V. All rights reserved.