Desalination of raw water using a polyamide hollow fiber membrane

An aromatic polymide hollow fibre membrane designed for a reverse osmosis system of 35,000 ppm total dissolved solids in take water was subjected to a low salinity of around 3000 ppm. The applied pressure and feed water temperature were varied to study their effects on permeation and salt rejection. The salt rejection was between 97 and 98%. High quality drinking water was produced at a pressure of 100 psig and room temperature (28-32°C). The performance of aromatic polyamide hollow fibre membrane manufactured by Horizon Desalinators (designed for seawater) was compared with Dow Chemicals thin film composite type spiral wound membrane made of aromatic polyamide (designed for brackish water). The performance of the hollow fibre membrane was better.