VARI-RO ™ “low energy” desalting for the San Diego region

This U.S. Bureau of Reclamation sponsored Desalting Technology Program Research study was directed at a 30 mgd desalination facility to be located in the San Diego region. The overall objective of the study effort was to show how the cost of seawater desalination can be reduced through the use of an alternate technology, the VARI-RO TM system (VRO), which is more energy efficient and environmentally attractive than existing methods. The VARI-RO TM technology is a highly efficient, low cycle speed, low pulsation, variable flow, positive displacement pumping and energy recovery system suitable for large capacity SWRO and BWRO projects. As compared to a centrifugal pump, energy recovery turbine, and variable speed drive system (CT); the following savings were projected for a 30 mgd SWRO facility: electric power savings 8 mW, percent savings 43 %, five year cost savings $26 million, thirty year straight line savings $156 million. As compared to the California State Water Project (SWP), power savings of 5 mW (megawatts) were projected. This means that desalting seawater can be less energy intensive that importing natural water. Also, substantial environmental benefits were projected, including: air emission reductions and lowering of reject brine concentrations.