New pretreatment media filtration for SWRO membranes of desalination plants

摘要

It is well known that seawater is contaminated with suspended solids, colloidal particles, and organic matters. Therefore, unless the contaminants are removed from the feed water prior reverse osmosis (RO) membrane, they will cause a severe membrane fouling problem by deposition on its surface. It is also known that the Foraminifera genus, Amphistegina, are found on the coasts of the Red and the Mediterranean Seas in very large quantities. Therefore, our attention in this paper is to evaluate the applicability of Amphistegina tests as new pretreatment media filtration compared with conventional sand filtration technique used for seawater desalination plants. In this work, Amphistegina tests were separated directly by sieving from fresh beach sediments with mesh size 1.0-1.5mm. According to the operating conditions for each media filtration system, the performance of the two different systems has been evaluated. From studying the filtrate quality parameters, both media filtration systems demonstrated a similar performance in removing particulates from the feed seawater and produced permeates of acceptable quality for feeding RO systems at different temperatures of 20, 30, and 40 degrees C and different flow rates of 20, 40, and 60l/min. The optimum conditions were obtained using 20l/min and 40 degrees C, and the amphistegina filter produced water with much better quality compared with that produced by sand filter. This study is based on a semi-pilot desalination unit located in the Egyptian Petroleum Research Institute (EPRI).