AWWA WQTC71539

This powerpoint presentation begins by providing a brief overview of water scarcity and barriers to reuse, osmotically driven membrane processes, and a hybrid forward osmosis (FO)/reverse osmosis (RO) process. Project objectives were to: investigate the performance and limitations of the forward osmosis process for pretreatment of impaired/reclaimed water, and of the combined FO/RO desalination hybrid system and its effects on membrane fouling and organic solute rejection; and, to develop recommendations and cost estimates for an FO/RO hybrid system. Experimental methods included: the bench-scale forward osmosis system; forward osmosis and reverse osmosis membranes; baseline performance test (bench); short-term fouling (bench); long-term fouling/rejection (pilot); and, solution chemistry. Solute transport and modeling of economic feasibility are presented, and conclusions are provided for: flux; fouling; multiple barriers provide adequate rejection of trace contaminants; and, the process is feasible over a wide range of operational parameters. Includes tables, figures.