CCD Series No-10: small compact BWRO closed-circuit desalination (CCD) units of high-recovery, low-energy and reduced fouling for supplied water upgrade to industry, irrigation, domestic, and medical applications

Abstract

The recently emerging new closed circuit desalination (CCD) technology enables performing high-recovery and low-energy BWRO desalination of reduced fouling irrespective of the number of elements per module and thus opened the door to a new class of small compact units for diverse applications. The design aspects and performance prospects of such small compact BWRO-CCD units (<5.4 m3/h; <130 m3/d) are illustrated with modules comprising either two or three elements each (MEn with n = 2–3). Since small compact BWRO units are extensively used for supplied water upgrade to industry, irrigation, domestic and medical applications, the unique performance characteristics of said small compact CCD units of high recovery and low energy is exemplified with feed of 200–750 ppm NaCl which cover the range of 230–900 ppm of ordinary supplied water sources worldwide. The supplied water upgrade by said compact CCD units are illustrated at the level of a single-pass quality permeates as well as at the level of double-pass quality permeates of exceptionally low salinity in the range 0.13–1.54 ppm depending on the feed salinity and the membrane salt rejection characteristics. The double-pass process in these compact CCD units implicate the use of first pass permeates as feed to the second pass, thereby enabling the same unit execute either a single or a double-pass process depending on the desired quality of permeate.