Independent testing of commercially available, high-permeability SWRO membranes for reduced total water cost

Abstract

Energy remains the major operating expense when producing desalted water by seawater reverse osmosis (SWRO). Recent advances in membrane materials and highly efficient energy recovery devices have drastically reduced the energy required to desalinate seawater over a wide range of system capacities. This study tests the performance of novel, commercially available, high-permeability membranes (including nanocomposite membranes) over an extended period of time. Tests were carried out utilizing a 125 m3/day SWRO system with independently verified continuous power monitoring. The desalination subsystem utilizes a staged membrane configuration and a low flux—low recovery design to minimize the overall energy consumption, reduce potential fouling, and reduce membrane cleaning. The specific power required to desalinate water to produce potable water having total dissolved solids below 400 mg/L was consistently below 2.0 kWh/m3 for feedwater temperatures above 20 °C using commercially available high pressure pumps and energy recovery devices.