SWRO Energy Consumption: Expectations and Reality for State-of-the-Art Technology

Abstract

The reverse osmosis (RO) membrane process in seawater desalination owes part of its success to lower energy consumption compared with thermal desalination processes. However, specific energy consumption (SEC) by seawater RO (SWRO) plants is influenced by numerous parameters. Basic design parameters for SWRO consist of net production capacity for treated water; composition of permeate and product water, including salinity, boron, bromide, and alkalinity; seawater salinity and temperature variations; and permeate recovery. Secondary design targets—pretreatment system, type of potabilization process, wastewater processing, and sludge dewatering—also influence energy consumption. This article explores how energy consumption depends on key design parameters; investigates how pretreatment procedures and first-pass RO membrane configuration in split partial mode influence SWRO energy consumption; and provides power consumption ranges based on a characteristic SWRO plant size, with various design and operating conditions, as well as plant subsystems.