Analytical approach integrated natural membranes MF-UF organic (MY). Part 1: In situ characterisations and models

Interest in coupling membranes autopsies and permeates analysis for a better management of fouling phenomena occurring in low-pressure MF/UF membranes. Successful utilization of membrane technology has been greatly limited by membrane fouling. Fouling increases operation and maintenance costs by deteriorating membrane performance (flux decline vs time) and ultimately shortening membrane life. Natural organic matter (NOM) plays an important role in membrane fouling. Humic substances as well as polysaccharides and proteins have been shown to exert fouling properties towards low- and high-pressure membranes. The overall objective of our work is to better characterize the nature of the fouling material, which is responsible for the reduction of permeability observed during low-pressure membrane filtration (MF and UF) of raw and chemically treated surface waters using hollow fiber modules. Our paper focused on the membrane caracterizations conducted on hollow fibers operated with a raw surface water and two synthetic solutions containing models foulants (humic acids and algal culture) using a large panel of analytical tools including novel technologies such as ESCA (Electron Spectroscopy for Chemical Analysis) and pyrolysis gaz chromatography/mass spectrometry in addition to FESEM (Field Emission Gun Scanning Electronic Microscopy), AFM (Atomic Force Microscopy), contact angle and zeta potential measurements. Complementary informations obtained from the analyses of the feed water, the permeate and the backwash water solution (DOC, UV254, High-pressure SEC, Total Amino Acids (AA) and Amino Sugar (AS), hardness, alkalinity) are also discussed. Furthermore, the cake layer model of fouling is developped to determine the modified fouling index parameters denoted MFI-UF and MFI-MF for a raw water from the Marne River (France) and two synthetics solutions (humics and algae), in order to predict fouling.