Characterization of the reverse osmosis membrane fouled by Oum Errabia river water of Khenifra city, Morocco

Abstract

The Khenifra desalination plant is designed to produce 36,290 m 3 /d of drinking water by 2030. Since the start-up of this plant in 2013, several problems have been encountered in the reverse osmosis unit due to membrane fouling. Clogging is a major issue related to the interaction between feed water quality and the pre-treatment process. Membrane autopsy, monitoring of seasonal variations in raw water and surveillance of operating parameters are carried out. The results obtained show that feed water is subject to large seasonal variations in terms of temperature (10 - 25 °C), conductivity (1395 - 2500 µS.cm -1 ) and Silt Density Index (SDI) (< 3) in 2017 using microfiltration, which influences the fouling of the membrane. Membrane autopsy by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray Diffraction (XRD), shows the formation of large cracks on the surface of the membrane and that the fouling layer is mainly composed of: CaCO 3 (38.70 %), Al 2 O 3 (17.42 %), Ba(SO 4 ) 2 (15.23 %), MgCl 2 (15.02 %) and SiO 2 (13.64%).