Operation and reliability of very high-recovery seawater desalination technologies by brine conversion two-stage RO desalination system

A reverse osmosis (RO) seawater desalination system has many advantages suc h as saving energy and using less installation space, and has become regula r technology to obtain fresh water from seawater. A significant way to lowe r energy and installation space is to raise system recovery, and we have de veloped anew RO seawater desalination system which provides 60% recovery of fresh water for 3.5% seawater. The new technology is called a brine conver sion two-stage SWRO system (BCS). This system includes several new technolo gies such as system configuration, energy recovery, operating condition, et c.; high-performance membrane technology; anti-biofouling technology and a new analysis method. A pilot plant has been operated successfully at Toray' s Ehime plant site since 1997. The first commercial plant of 4500m(3)/d (1. 2mgd) has been operating successfully since March 1999 in Mas Palomas (Gran Canaria, Spain). The Tortola and Curacao plants in the Caribbean have been installed with the fall BCS (first- + second-stage RO system), and also op erated under good conditions. A new application of the BCS, installed at th e Muroto plant in Japan, has been in operation to obtain bottled drinking w ater and high concentrated mineralized water from deep seawater. Furthermor e, other plants are under construction in Spain and the Caribbean. The BCS is presumed to be the standard SWRO system for the 21st century.