A membrane module is available for the purification of a flow of brine that contains 30,000 ppm of NaCl. We need to process 1000 kg/h, and the permeate represents 75% of the initial flow. The concentration of the permeate must be 200 ppm of NaCl. Determine the average pressure applied to the feed side. The feed is at 9000 kPa and the concentrate at 8500 kPa. The discharge of the permeate occurs at atmospheric pressure.

Water permeability is 2.0531026 kg/m2 s kPa.

Salt permeability is 4.0331025 kg/m2 s.