Rever- make that - Forward Osmosis
In our class we have spent a decent chunk of time talking about water shortages and how pollution of water sources multiplies that problem. We also addressed recently the issue of what to do with all the waste water that hydraulic fracking creates. Treating waste water or polluted water is often impossible using traditional reverse osmosis because the water pressure required to overcome the high salinity of these waters would cause its membranes to shred. The only option previously available to purify such contaminated waters was thermal evaporation, a process that uses 25–50% more energy than forward osmosis.
While desalinating water is still completed cheapest using reverse osmosis, forward osmosis technology offers an option to treat extremely polluted waters using a relatively small amount of energy. Forward osmosis can be used however to treat extremely salty water solutions in countries enacting zero liquid discharge policies. These policies prevent countries from dumping the leftover solids and liquids into the ocean after the freshwater has been separated and collected. The reason countries are adopting these policies is dumping the large amounts of excess salt back into the ocean potentially damages surrounding ecosystems. This is an extremely interesting technology and I cannot wait to see further applications it is developed for. In my mind, I see great opportunities for this to adopted for uses such as cleaning waste water from power plants and perhaps even large scale in waste water treatment facilities.
McKenna, Phil. “Purifying the Dirtiest Waters” “PBS: NovaNext” April 29, 2015












