Characterising the Performance and Fouling of Hollow Fibre Membranes: Final Report

Hollow fibre membranes and membrane bioreactors (MBRs) have been actively used for municipal and industrial wastewater treatments [1]. The two main issue hindering wider applications of this technology are the high cost of membrane materials and membrane fouling [2-4]. On the latter case, the efforts of research institutes and the industry sector are focused on understanding the mechanism of fouling, the nature of foulant, visualising and direct monitoring of fouling [2, 5]. Usually, fouling and its dependencies are characterised from filtration data [6]. In situ methods are preferred because they do not involve potential changes of feed or permeate properties by sampling or storage [2]. The basic of most in situ methods developed for detection of fouling in MBRs is measuring filtration parameters such as flux and trans-membrane pressure. In the present study, we examined the feasibility of using electrical measurements for monitoring of fouling in MBRs. For this, we used an electrical impedance spectrometer (EIS). EIS measures the electrical impedance (i.e. the complex electrical resistance) by injecting a small signal to the sample and measuring the ratio of an alternating voltage to its corresponding current and the phase difference between them [7, 8]. Therefore, EIS can potentially be used as a simple non-destructive method to monitor the filtration process in MBRs [9].