Association for Public Policy Analysis & Management

Water supplies increasingly are becoming strained due to population growth, agricultural and industrial development, and global climate change. Seawater reverse osmosis (SWRO) membrane desalination technology has the potential to meet the growing worldwide demand for freshwater by securing the most abundant resource of surface water available on the planet: the ocean. As water demands in communities around the world exceed existing storage capacity of reservoirs and deplete groundwater sources, SWRO has become a more accepted approach to augment the world’s existing freshwater supply, especially in arid regions such as the Middle East.

Coupled with recent advances in membrane technology and sustainable sources of energy for operation (such as solar or wind power), SWRO is transitioning from a viable alternative to an integral component of freshwater provisions for many coastal areas worldwide. However, there are numerous impacts of SWRO on both the environment and society. It is especially controversial in Southern California, where environmental groups are clashing with desalination developers.

This study examines both the positive and negative impacts of SWRO compared to other water management options such as reuse and built storage. Key questions addressed are – what are the environmental impacts of SWRO compared to wastewater reuse? How can SWRO enhance the reliability of water supply and what is the value of this increased reliability?

Our interdisciplinary team of students assembled data on SWRO capital investment, energy footprints, operation cost, and environmental impacts. We then used nonmarket valuation to quantify the economic impacts of improving the current desalination technology. Technological improvements we assessed include the dynamic control of desalination water production rate to synchronize with peak energy curve; improvement of membrane technology for membrane fouling reduction; application of “smart” feedback system for pretreatment optimization; and brine recovery for environmental impact minimization. Furthermore, we conducted comparative analysis on environmental and community impacts of SWRO with wastewater reuse practices.

To best represent a realistic desalination system, we used coastal Southern California as a case study. SWRO is actively being explored in this region as a solution to supplement ever increasing drinking water demands, where at least six new facilities have been proposed. A hypothetical 50 million gallons per day (MGD) (1.89 × 105 m3/day) SWRO desalination facility, located in Huntington Beach, CA, was used as a case example to illustrate the validate of SWRO as a source of drinking water supply.