Optimal Water Backwashing Condition in Combined Water Treatment of Alumina Microfiltration and PP Beads.

Hyungmin Cho,Jin Yong Park,Gihoon Yoon,Minjae Kim

doi:10.3390/membranes12010092

Abstract

Membrane fouling is a dominant limit of the membrane separation process. In this research, the optimal water backwashing to solve the membrane fouling problem was investigated in the combined water treatment process of alumina MF and pure polypropylene (PP) beads. Additionally, the influence of membrane shape (tubular or seven channel) was examined, depending on the water backwashing period. The optimal backwashing time (BT) could be 20 s in the combined water treatment process, because of the highest total treated volume (VT) in our BT 6–30 s conditions. The optimal backwashing period (BP) could be 6 min, because of the minimum membrane fouling and the maximum VT in the combined process of tubular alumina MF and PP beads. The resistance of reversible membrane fouling (Rrf) showed a major resistance of total membrane fouling, and that of irreversible membrane fouling (Rif) was a minor one, in the combined process using tubular or seven channel MF. The Rif showed a decreasing trend obviously, as decreasing BT from NBW to 2 min for seven channel MF. It means that the more frequent water backwashing could be more effective to control the membrane fouling, especially irreversible fouling, for seven channel membranes than tubular membranes.

Highlights

In the membrane separation process, usually, membrane fouling was accomplished by the adsorption-precipitation of organic and inorganic compounds on the membrane surface or inside the membrane and leads to decreasing the permeate flux, increasing membrane cleaning costs, and reducing the membrane life
Strategies for reducing membrane fouling remain insufficient, that is, the major hindrance in the successful application of membrane separation technology, considerable progress has been made in membrane fouling control [1,2]
The anti-adhesion method which prohibits the initial attachment of bacteria on a membrane surface was more efficient than the anti-bacterial approach that focuses on killing bacteria already involved on the membrane surface [2]

Summary

Introduction

In the membrane separation process, usually, membrane fouling was accomplished by the adsorption-precipitation of organic and inorganic compounds on the membrane surface or inside the membrane and leads to decreasing the permeate flux, increasing membrane cleaning costs, and reducing the membrane life. Strategies for reducing membrane fouling remain insufficient, that is, the major hindrance in the successful application of membrane separation technology, considerable progress has been made in membrane fouling control [1,2]. The modified membranes were investigated for their anti-biofouling performance in the viewpoints of the anti-adhesion and anti-bacterial effects. The anti-adhesion method which prohibits the initial attachment of bacteria on a membrane surface was more efficient than the anti-bacterial approach that focuses on killing bacteria already involved on the membrane surface [2]. Natural organic matter (NOM) is a dominant constituent of membrane fouling in lowpressure membrane filtration. A new adsorbent, such as heated aluminum oxide powder, was employed in an absolutely automated pilot water treatment process to exclude NOM in the surface water [4]

Methods

Results

Conclusion