The Crossflow Sampler - Modified Fouling Index Ultrafiltration (CFS-MFIUF) as a water quality monitoring tool

摘要

Silt Density Index (SDI) and Modified Fouling Index (MFI0.45) are the current approaches to measure the fouling potential of reverse osmosis (RO) feed water. The major drawbacks of these methods are that both methods are operated under the pressurised dead-end mode and particles with size less than 0.45um are not incorporated in the test. As a result, MFI-UF and NF- MFI were developed subsequently utilizing ultrafiltration and nanofiltration membranes, respectively, to capture the smaller foulant particles. However, none of these indices has considered the role actual RO hydrodynamic crossflow conditions in the measurement in terms of its effect on particle fractionation and capture. To address this issue, an alternative fouling index, known as Crossflow Sampler - Modified Fouling Index Ultrafiltration (CFS-MFIUF) is developed in this study. During the measurement, the incoming feed first goes through a crossflow filtration cell, then the permeate is directed to a dead-end MFI measuring device. The purpose of this crossflow cell is to fractionate the incoming feed hydrodynamically in order to obtain a more representative sample of RO foulants. In order that there is consistency in terms of particle capture and fractionation, our CFS- MFIUF experiments is chosen to be operated under constant flux rather than under constant pressure.