AG2 - Clay deposit removal from membranes Extract from the paper "Cleaning Clay from fouled membranes", to be presented at Euromed 2008, Jordan Desalination Cooperation among Mediterranean countries of Europe & the MENA region, 9-13 November 2008.

Genesys membrane laboratories in Madrid show that the majority of deposits found on reverse osmosis membranes are clay based aluminosilicates .These deposits are difficult to remove with traditional cleaning chemicals, Genesol 703 is a speciality membrane cleaning chemical designed to effectively remove these and other deposits reducing membrane cleaning frequency and associated costs. Results of cleaning trials on actual membranes are presented. Membrane clay deposits Within the lifetime of most reverse osmosis (RO) systems some fouling will adversely affect membrane performance with the nature of the foulant generally being determined through membrane autopsy. Autopsy results show that the major constituents of these deposits are aluminosilicates or clays. Clay minerals are generally categorized as being <2µm in size and are formed by the gradual chemical weathering of silica bearing rocks which over time are transported into natural water sources and will therefore occur in all RO feed waters. Due to this small size they are difficult to remove from feed water by conventional chemical and physical pre-treatment methods. Clay minerals have traditionally proved difficult to remove effectively from membranes using conventional cleaning chemicals. The incomplete removal of these deposits leads to a higher cleaning frequency, an increase in operational costs and also an enhanced potential for membrane damage.