Problem 2: Each pressure vessel (containing 200m2 of membrane area) in a proposed design for desalination of seawater (35,000mg/L dissolved salt concentration) is rated for 35% recovery at flow rates between 850 and 1,300 m3/d. Design a multi-stage array system that will yield 2,000m3/d of pure water for a town of 5,000 people at a total permeate recovery of 50%. In your design it is suggested to operate with flows to each pressure vessel on the conservative side of the flow range allowed to provide a design safety factor. The mass transfer coefficient for water flux of 7104m3/dm2kPa, and assume 100% rejection of salts by the membranes. (a) For each stage of the array system, determine the number of pressure vessels to operate in parallel and the minimum required net transmembrane pressure (in kPa ). (b) Estimate the dissolved salt concentration in the reject stream from the multi-stage array system. (c) Sketch the system diagram