Pretreatment of Seawater for Reverse Osmosis

Abstract

The objective of this work is to study the components in seawater and the pretreatment system which affects the performance of reverse osmosis process. Scales of sulfates and carbonates,colloids, metal oxides and microorganisms were the major components in which removal was necessary.The appropriate pretreatment system for these components should consist of a 5 pm cartridge filter, chemicals dose, activated carbon filter and a 1 pm catridge filter respectively.

Reverse osmosis of pretreated seawater gave higher flux and salt rejection and low accumulation on the membrane surface compared to untreated seawater. Operating conditions such as recovery(%), pressure and flow rate changed permeation flux and it can be explained by surface accumulation and flow resistances. Salt rejections were independent of operating conditions and were 98.6-99.0 %

Reverse osmosis of synthetic solutions consisting of NaCl, MgCl, and CaSO, showed that the membrane was most affected by sulfates with the rate of flux decline of approximately 8 %