AWWA MTC64637

The objectives of this slide presentation were to outline the viability of ammonia-carbon dioxide (NH₃-CO₂) forward osmosis; evaluate membrane performance under a variety of feed and draw solution concentrations; and, evaluate energy use. The presentation provides a schematic of the experimental setup, a homogenous dense membrane, an asymmetric membrane (FO mode), and figures are given for membrane performance results and energy usage. Concluding remarks include: NH₃-CO₂ forward osmosis may be a viable desalination alternative; internal concentration polarization significantly hinders performance, ICP is more severe for higher draw solution concentrations; the presence of ICP forces the use of higher draw solution concentrations, increasing the load on the draw solute recovery system; and, tailoring of a membrane for forward osmosis would help reduce ICP phenomena and hence reduce energy requirements and increased GOR. Includes figures.