DuPont Permasep Products (A business unit of E. I. du Pont de Nemours & Company)

Du Pont introduced its first reverse osmosis permeators for water desalination in 1969 under the trade name "Permasep" as a result of its contusion research in polymer chemistry and synthetic fibers. Du Pont designed two types of permeator membranes, hollow-fiber and spiral-wound.

Du Pont made the hollow fiber B-9, the first Permasep permeator commercially available in 1969. Following the introduction of the B-9, Du Pont continued to unveil new and refined permeator models. For its innovation in developing the Permasep B-9 permeator, the company was awarded chemical engineering's Kirkpatrick Chemical Engineering Achievement Award in 1971. Du Pont introduced the B-10 permeator, the first permeator to make seawater desalination commercially feasible, in 1974. In 1989, Du Pont Permasep patented a chloramines process that created reliable biological control of surface seawater plants and prevented the formation of trihalomethanes created when water is treated with chlorine. In 1991, Du Pont sold the spiral wound permeator section of their business to TriSep. The sale of the spiral wound permeators left Du Pont to focus on developing more efficient hollow-fiber permeators. In 1992 Du Pont introduced the B-10 Twin permeator. The Twin drastically reduced operation costs and was more efficient than the standard B-10. Permasep, originally part of the Du Pont's polymer sector, was switched to the fibers sector in 1993 where it joined fibers like Kevlar and Nomex.

By 1997, Du Pont had sold over 1.5 billion gallons of desalting capacity. Du Pont had Permasep sales offices in seven countries: United States, Japan, United Kingdom, Switzerland, Saudi Arabia, Germany, and Belgium. These offices sold Permasep products across the globe, especially the Middle East. Customers there included Jordan, Kuwait, Libya, United Arab Emirates, Iraq, Iran, Saudi Arabia, and Bahrain, which had the world's largest reverse osmosis plant. Other countries include Malta, the Canary Islands, Italy, Venezuela, Chile, Morocco, and Singapore. Despite Permasep's success, Du Pont decided to discontinue production of hollow-fiber permeators in 1997. The reverse osmosis market slowly shifted away from hollow-fiber permeators towards spiral wound permeators. This shift was the deciding factor in decision to discontinue production.