(743e) Cost Optimization of Osmotically Assisted Reverse Osmosis

Authors: 
Bartholomew, T., Carnegie Mellon University
Siefert, N., National Energy Technology Laboratory
Mauter, M., Carnegie Mellon University
Safe and cost-effective management of high salinity brines is a critical enabler of inland brackish water desalination, produced water treatment, geothermal energy production, and CO2 sequestration. While reverse osmosis is considered the most energy efficient and cheapest desalination technology, the process has limited effectiveness for brines with salinities greater than seawater. In this work, we assess the techno-economic viability of a membrane-based process capable of desalinating high salinity brines, osmotically assisted reverse osmosis (OARO). We develop a non-linear optimization model to minimize the product water costs and extract generalizable guidelines for low cost design and operation of the OARO process. We estimate that the OARO process has lower or similar costs to mechanical vapor recompression, the current benchmark for high salinity brine desalination technology. We find that membrane costs account for the majority of OARO process costs, which suggests that advances in membrane properties and manufacturing may reduce OARO process costs significantly.