Nylon screen incorporated into hollow fiber microfiltration system for wastewater treatment

Low permeate flux due to clogging is the major challenge of hollow fiber microfiltration systems in wastewater treatment because of the high content of suspended solids. In this research, a new crossflow microfiltration module to overcome this problem was studied. The module consisted of a housing, a cylindrical membrane and a bundle of hollow fibers. The nominal pore size of the cylindrical membrane was 5 μm and that of the hollow fibers was 0.1 μm. The cylindrical membrane worked as a screen for pretreatment to remove those particles larger than its pore size and therefore to reduce the solid loading to the hollow fibers. Extensive experiments were conducted under various transmembrane pressures, influent concentrations, and crossflow velocities with polydispersed suspensions prepared with ISO Test Particles of size ranging from less than 0.5 μm to 10 μm. The quantity and quality of the filtrate were monitored over time. The results have shown that the cylindrical membrane worked effectively in reducing solid fouling, and therefore increasing permeate production for the hollow fiber microfiltration system.