MEMBRANE AUTOPSY - A CASE-STUDY

This paper describes the authors' experiences of membrane autopsy proc edures to identify the cause of poor membrane performance at a Europea n power plant and the subsequent proposals made for improvement to the operating, pretreatment and cleaning programmes. The reverse osmosis (RO) system is a 2,500 m(3)/d unit producing water for cooling purpose s. The 3-year-old plant experienced continual output loss, which requi red the membranes to be cleaned on a twice weekly basis, which increas ed to every 4 days in warm weather. The autopsy objective was to carry out a destructive analysis on a fouled membrane to identify the major causes of the fouling. These were identified as being biological in n ature with the significant presence of iron, which together formed a b iomass on the membrane surface.