More recently, there has been increasing use of RO in reclamation of wastewater for indirect potable use. For example, the recent implementation of the GWR facility in Orange County produces 280,000 m3/d of treated wastewater that is used to augment the groundwater in the region that supplies local municipalities with drinking water. (Franks 2004) RO plays an integral role in the advanced treatment process used at this plant. At this plant, low pressure, high rejection ESPA2 membranes are used to make RO permeate with less than 50 mg/l TDS. But more importantly, RO membranes are extremely valuable for ensuring that the reclaimed water is safe for potential potable reuse. Wastewaters can contain a range of organic contaminants, including pharmaceutical compounds, personal care products, pathogens, disinfection by-products, and pesticides. Due to their complex structure, they are often poorly degraded by bacteria during the activated sludge process. Also, due to their water solubility, they can stay dissolved in water and not be removed in the sludge. Thus, they can present a threat to the safety of reclaimed water, making RO separation a key step in the safe recovery of water from wastewater sources.