Comprehensive bench- and pilot-scale investigation of trace organic compounds rejection by forward osmosis. Environ

1 S1 – The FO-RO dual barrier system for high efficiency water purification Our recent study has demonstrated the effective dual barrier characteristics of the FO process when hybridized with seawater RO for treatment of secondary and tertiary treated do-mestic effluents (Cath et al. 2010). In the process impaired water is first treated by an FO mem-brane and water is drawn into a seawater draw solution (DS) and the diluted DS is desalinated by RO to produce a stream of purified water. The basic configuration of the hybrid FO-RO process is illustrated in Figure S1. The osmotic dilution approach may provide at least four major bene-fits related to water and energy resources. These include lower energy and higher recovery sea-water desalination, multi-barrier protection of drinking water, reduction in reverse osmosis membrane fouling due to impurities in impaired water, and beneficial reuse of impaired water. Figure S1. Two configuration of the hybrid FO-RO process: (a) closed loop DS in which the FO recovers water from an impaired stream and the RO reconcentrated the DS for reuse and simul-taneously produces purified water, and (b) open loop DS in which the FO recovers water from an impaired stream that dilutes pretreated seawater on the way to a seawater reverse osmosis pro-cess. The rejection of wastewater constituents such as organic carbon, nutrients (i.e., ammonia, nitrate, phosphate), and suspended solids by the two tight barriers (FO and RO) was very high (95-99.9%), the FO membranes protected the sensitive RO membranes from fouling and scaling, and energy saving was calculated. (a) (b