Comparison of Membrane and Granular Media Pretreatment, Toxin, and Boron Rejection Results, and Energy Recovery Update in Carlsbad, California

The Carlsbad, CA seawater desalination demonstration pilot facility started up in late 2002 and began continuous, 24 hr / 7 day per week operation in early 2003. The facility is fed water from the Agua Hedionda lagoon after having been through the power plant cooling system. The lagoon is under the influence of surface water runoff from Agua Hedionda Creek, experiences daily temperature variations, and is subject to exposure to red tide and algal blooms. This paper will address key, current technical issues within the desalination community by presenting a performance comparison of pretreatment ultrafiltration membrane (1) and granular media filtration. Other testing results will be presented and discussed, including boron challenge testing and seawater membrane rejection at various pH values which will be compared to California, EPA and WHO standards; a boron speciation technical primer; and results of domoic and saxitoxin testing experienced during a red tide event.