It has been well over 20 years since DuPont first invented the hollow-fiber permeator and the single-bundle reverse osmosis (RO) aramid membrane used inside it. In the intervening years the B-9 brackish and B-10 seawater devices were commercialized and became standards in the field for the production of high-quality desalted water. Many improvements were made to the permeators and the technology for desalination. DuPont has now commercialized a new RO device, a double-bundle permeator, which builds on the knowledge gained in thousands of RO installations. This paper discussed the development and commercialization of this TWIN(TM) permeator: how the bundle design and fluid flow patterns were optimized and the inventive concepts required to provide a mechanically stable product. Field test data and the commercialization of this new module are reviewed.
