The removal of sulfate from injected seawater for waterflood and pressure maintenance operations has become widely accepted for reservoirs with sulfate scaling potential. The technology has been found to be exceptionally useful in deep water and subsea operations where scale controls using scale inhibition squeeze treatments become prohibitively costly. Twenty five sulfate removal facilities are now operating or being built off the cost of West Africa, Brazil, and in the North Sea. Experience with these existing facilities has identified methods to minimize the size of the sulfate removal facility with accompanying weight and space savings which often exceed the capital cost of sulfate removal system itself. Similar savings and trends have been identified by the availability and successs of auxiliary pre-filtration equipment. Operation cost reduction and improved reliability have been achieved by selecting raw seawater intake reduction and improved reliability have been achieved by selecting raw seawater intake locations, the re-design of sulfate removal system. The careful selection and evaluation of sulfate removal system components, including fine filtration and deaerators, have resulted in significant savings by extending membrane life up to twice the warranty period and by reducing operation costs of 25% than originally projected.