A Rotating Hollow Fiber Module for Fouling Control in Direct Membrane Filtration of Primary Settled Wastewater

Abstract

Direct membrane filtration (DMF) has emerged as an attractive option to treat municipal wastewater; however, this technology suffers from severe membrane fouling. In this paper, a rotating hollow fiber module for enhancing the fouling control is proposed. The experimental study was conducted at lab scale, filtering a primary settled municipal wastewater. The effectiveness of this technology coupled with physicochemical pretreatment was also evaluated. Results showed the existence of a threshold permeate flux (32–36 L/h·m2), below which the shear rates exerted by membrane rotation prevented supramicron size particle deposition, regardless of the application of physicochemical pretreatment, even at low rotational speeds (w = 120 rpm). At higher fluxes (40–48 L/h·m2), the rotational speed had to be increased to 340 rpm to achieve sustainable conditions. Even when applying physicochemical pretreatment, the internal residual fouling was found to be the main fouling contribution, probably associated with the submicron particles.