Switchable Polarity Solvent Forward Osmosis Converts Fracking Wastewater into Potable Water

Idaho National Laboratory (INL) has developed a new technology that could turn fracking wastewater into potable water. Switchable Polarity Solvent Forward Osmosis (SPS FO) aims to alleviate criticism directed towards hydraulic fracturing- a process that produces 3 to 5 million gallons of concentrated wastewater per drill site.

INL researcher Aaron Wilson and his team have developed SPS FO, a technology that combines two known processes to create a brand-new, efficient water-filtration system. SPS FO can cleanse highly concentrated industrial wastewater to make purified water. The technique has won several outstanding innovation awards, including a 2013 R&D 100 Award, an Idaho Innovation Award for Early-Stage Innovation, and an Outstanding Technology Development Award from the Federal Laboratory Consortium Far West Region.

Osmosis purifies water by drawing out dirty, contaminated wastewater through a membrane and pulling it into an even more concentrated solution. In order to create that concentrated solution, Wilson used switchable polarity solvents (SPS). For the membrane, he asked the help of Fred Stewart, an INL expert in membrane research, to find a delicate, highly porous membrane that allowed only water to pass through.

The whole SPS FO process starts with wastewater pumped past one side of a membrane and the SPS solution simultaneously pumped past the other side. The SPS solution is a combination of amines, water and a CO2 trigger that creates a solution more concentrated than the wastewater.

Heat is then applied to separate the pure water from the SPS solution. This procedure causes carbon dioxide release, turning the remaining SPS solution into an oily liquid. The solution then separates from the water and is siphoned off. The CO2 gas and now-oily SPS solution are fed back through the system, where the reintroduction of CO2 triggers a polarity switch. This switch changes the nonpolar oil back to a polar salt solution. The ability to switch between oil and a salt is what makes this a closed-loop system, ensuring a continuous flow of SPS solution.

SPS FO technology is used in nuclear, natural gas and petroleum industries. Developments such as this pave way for real life applications. Aqua Solutions offers high capacity frame mounted RO pretreatment systems with high production rates for the removal of contaminants in tap water. High-quality purification systems, like SPS FO and Aqua Solutions’ RO pretreatment system, can deliver the highest purity reagent grade water for laboratory applications.