Characterization of the Initial Fouling Layer on the Membrane Surface in a Membrane Bioreactor: Effects of Permeation Drag.

Shengli Wang,Jingbo Guo,Haifeng Zhang,Xin Lu,Lanhe Zhang

doi:10.3390/membranes9090121

Abstract

In this study, the properties of the initial fouling layer on the membrane surface of a bioreactor were investigated under different operating modes (with or without permeate flux) to improve the understanding of the effect of permeation drag on the formation of the initial fouling layer. It was found that protein was the major component in the two types of initial fouling layers, and that the permeation drag enhanced the tryptophan protein-like substances. The attraction of the initial foulants to the polyvinylidene fluoride (PVDF) membrane was ascribed to the high zeta potential and electron donor component (γ−) of the membrane. Thermodynamic analyses showed that the permeation drag-induced fouling layer possessed high hydrophobicity and low γ−. Due to permeation drag, a portion of the foulants overcame an energy barrier before they contacted the membrane surface, which itself possessed a higher fouling propensity. A declining trend of the cohesive strength among the foulants was found with the increasing development of both fouling layers.

Highlights

Membrane bioreactors (MBRs) are gaining worldwide attention as a promising solution for wastewater treatment
It is widely known that biofouling starts with the deposition of foulants during the initial stages of membrane filtration, resulting in the development of additional fouling layers on the membrane surface [4]
The intensity of peak A was 79.2% higher under normal conditions and was significantly higher than the intensity of peak B (34.7% higher), indicating that the flux conditions and was significantly higher than the intensity of peak B (34.7% higher), indicating presence of the permeation drag force had a more important influence on the adhesion of tryptophan that the presence of the permeation drag force had a more important influence on the adhesion of tryptophan protein-like substances than that of other protein fractions on the membrane surface

Summary

Introduction

Membrane bioreactors (MBRs) are gaining worldwide attention as a promising solution for wastewater treatment. These reactors have many advantages over conventional activated sludge systems, such as a smaller footprint and better effluent quality, which enables reuse [1,2]. Membrane fouling, especially biofouling, has been the main obstacle for the wide application of MBRs [3]. It is widely known that biofouling starts with the deposition of foulants during the initial stages of membrane filtration, resulting in the development of additional fouling layers on the membrane surface [4]. The initial fouling layer plays a significant role in the membrane filtration process and requires more consideration

Objectives

Results

Conclusion