Dr. Vaibhav Bahadur, a professor in Mechanical Engineering (ME) and an affiliate member of TMI, and ME graduate student Shanthanu Katakam, have developed a new method for designing and predicting performance of an emerging desalination technology: Osmotically Assisted Reserve Osmosis (OARO). OARO is an advanced version of well-known reverse osmosis (RO) technology, which uses membranes to separate fresh water from saline water.
Industries like oil and gas and textile manufacturing produce extremely salty wastewater (called hypersaline brine), which is hard to treat. Reducing the volume of this brine is important because it lowers the energy needed for crystallizers and makes water recycling and mineral recovery more practical. Traditional thermal methods, such as Multi-Effect Distillation and Mechanical Vapor Compression can handle the high salt content but are expensive and energy-intensive. RO systems need far less energy, but RO membranes cannot handle high salt content in water, limiting their utility. Osmotically Assisted Reverse Osmosis (OARO) is a new technique that helps overcome the challenges in conventional RO. It uses an extra “draw solution” in the process, making it possible to treat very salty water without exceeding membrane limits. OARO still relies on mechanical work (not boiling water), so it uses much less energy than thermal methods.
Current methods to model and analyze OARO systems rely on complex mathematical modeling that is computationally expensive and often impractical. In contrast, the first-principles-based model developed by Shanthanu and Dr. Bahadur can enable design and performance calculations without relying on complex simulations, while still accounting for various real-world factors. When tested, the model was accurate to within 6% while being much faster than computational simulations. This model can be the basis of design and optimization of future OARO systems for applications such as dewatering for lithium extraction and produced water treatment.
Their new approach can help industries manage waste brine more efficiently, saving both energy and its environmental impact.To read more about their model, read "Heat-mass transfer analogy-based design method for Osmotically Assisted Reverse Osmosis membrane mass exchangers" in Desalination.
