AWWA MTC64530

Several full-scale seawater desalination projects are currently under development in the USA, many of which are envisioned to include co-location at a coastal power generating facility. These power generating facilities use large volumes of seawater for cooling, which offers the desalination facility the ability to obtain feed water and concentrate disposal through existing seawater intake and outfall infrastructure. Therefore, the desalination process has the option of operating on the ambient temperature intake or the warmer power-plant cooling-loop discharge. West Basin Municipal Water District has operated a long-term pilot testing program to evaluate desalination technology on both sources. The testing has occurred over a four-year period at the El Segundo Power Generating Station in El Segundo, California. This paper provides data on the operation of membrane pretreatment processes as well as reverse osmosis membranes. A membrane desalination plant operating on the warmer return water would have the advantage of a decreased energy usage associated with a decrease in water viscosity. On the other hand, the salinity of the product produced from the warmer water would be slightly higher in concentration. In addition, the warmer water may promote biological growth, which could cause a higher fouling potential for the membrane treatment processes. For these reasons both feed sources warrant investigation. The data set is considered unique and of substantial value to the seawater desalination community, because it provides comparative data (ambient and warm water sources) from the same power plant seawater intake. One of the primary goals of the test program is to establish the performance of pretreatment and desalination processes on each source. This information will provide designers and developers of full-scale desalination projects direct comparisons that have not been previously available. Previous publications on the project have reported early performance of microfiltration and reverse osmosis on the ambient temperature intake and various pretreatment process iterations, involving chloramination and pre-strainers. Includes 6 references, tables, figures.