Economic Comparison of Pressure Driven Membrane Processes to Electrically Driven Processes for Use in Hydraulic Fracturing

Hydraulic fracturing has provided many new resources for the United States in oil and gas. These resources continue to be an economic driver going forward in many areas of the country. However, significant challenges remain with the environmental sustainability of this technology. One of the areas that is of particular concern is the re-use of the water that is used in fracking operations. The current method of dealing with this water, deep well injenction, takes water out of the eco-system and has been shown to cause earthquakes. This water has high levels of suspeneded and disolved organics as well as high levels of dissolved salts. Because of this the osmotic pressures of these streams are significantly more than seawater reverse osmosis in several instanced. Our group has looked at several possible alternatives of dealing with this water including reverse osmosis, nanofiltration, electrodialysis, and electrodeionization. All of these technologies have different advantages depending on the concentration of the water and ultimate re-use objective. This study has shown that electrodeionization is the most flexible technology, due to selective ion removal and high water recoveries, with the potential to work for both re-use and drinking production as well as acceptable economics at high and low ion concentrations. Experimental results as well as economic modeling will be presented in this talk.