DRINKING WATER FROM THE SEA: REVERSE OSMOSIS, THE MODERN ALTERNATIVE

In this paper, the authors outline the principles of reverse osmosis and its development and explain the design of RO plants for shipboard applications. Different types of membrane are described ogether with details of their application, in single-pass and two- pass RO systems. Associated subjects such as pretreatment, control and operation and maintenance are also discussed. Cost comparisons and power consumption figures are given for RO and the more conven- tional shipboard desalination systems such as multi-stage flash and vapour compression. These show that RO is now economically attractive compared to the other systems and has the added attractions of simplicity and low maintenance.