INTERACTION OF SOLUBLE ORGANIC MATTER WITH METAL OXIDES USED AS CERAMIC MEMBRANE FOR DRINKING WATER PRETREATMENT

摘要

Throughout the world, a trend to intensify use of desalination as a means to reduce current orfuture water scarcity is observed. Membrane desalination is an extremely good technique for theremoval of colloids, dissolved organic matter and salts. However this technique is very sensitiveto fouling. Therefore, it is important to control the fouling of the Reverse Osmosis membrane toinsure a long lifetime of the membrane. Pretreatment is a good way to control the fouling. In thisproject, ceramic membrane ultrafiltration is considered as pretreatment before RO. Interactionsbetween organic matter from different sources and ceramic membranes are studied to evaluatethe efficiency of ceramic ultrafiltration as a pretreatment before RO. Terrestrial organic matterextracted from a treatment plant and marine organic matter from algae culture and sea areinvestigated. These organic materials show different organic content, hydrophobic character andmolecular weight distribution (LC-OCD profiles). Filtration of marine organic matter leads tohigher fouling than terrestrial organic matter (decline of 85% in the first ten minutes forChlorella vulgaris exudates), for a smaller content of organic matter (DOC of marine solutions =3–4 mg/L; DOC of brackish water = 10 mg/L). Analyses of backflush and chemical cleaningsolutions show that Low Molecular Weight (LMW) compounds and High Molecular Weight(HMW) compounds are preferentially retained in the ceramic membrane.