Out of their initial efforts toward building a 'super capacitor' for desalinating sea water into drinking water for the military, a startup has developed a new desalination system that could take on some of the oil and gas industry's wastewater for reclamation.
The petroleum industry uses a lot of water every year, and a huge portion of that water ends up as salty wastewater, unable to be used again without intensive processing. But the new desalination system from Atlantis Technologies, called Radial Deionization (RDI), is claimed to be a "low-cost, chemical-free desalination system that can remove salt from oil, gas, mining, and industrial waste water."
RDI systems are said to be able to safely clean salty wastewater at up to 75% less of a cost than other current systems, such as brine concentrators or reverse osmosis. The system can process water containing silica and barium/calciumstrontium sulfate, and can treat high total dissolved solids (TDS) streams such as water from hydraulic fracturing and wastewater from reverse osmosis plants, as well as high TDS acid from mine drainage.
Here's the tech info on the units:
"A stream containing salt is passed between two oppositely charged super capacitors (electric double layer capacitors, or EDLC). As the liquid passes through the dielectric spacer separating the capacitors, charged ions are attracted to the oppositely charged capacitor layers. The ions leave the process stream/dielectric layer, pass through a charge specific membrane, and are adsorbed onto the surface area of the electrode. When the capacitors have filled with ions, the polarity is reversed and the ions are discharged back into the dielectric spacer and removed from the system. A 3-way valve is situated at the outlet of the device(s) which directs the discharged ions away from the previously cleaned process stream." - Atlantis Technologies
The company's system is modular, capable of being connected together in series or parallel to form a larger system, and operates using 25% to 75% less energy than the most energy efficient brine concentrators now available. The RDI system can recover up to 95% of the water, is able to be adjusted to concentrate the elements in the outgoing water (for recapture), and is scalable up to flow rates up to 1,000 gallons per minute.