EVALUTATION OF A HYBRID TREATMENT SYSTEM FOR FRACKING WASTEWATER

Daniel ChaThe United States’ pursuit of energy independence since the 1970s introduced a hydraulic fracturing (fracking) revolution for natural gas as a fuel source. Marcellus Shale in Pennsylvania has been the focal point as it is the largest known shale reserve in the U.S. and possibly the world, with approximately 77.2 trillion ft3 of natural gas production potential. Fracking presents significant issues for the communities associated with the process. The highly contaminated brine wastewater produced from fracking wells is not treatable in municipal treatment plants. Additionally, induced seismic activity in Youngstown, Ohio has been caused by the primary fracking wastewater disposal technique, deep-well injection. Characterizations have shown that the wastewater is composed of high levels of suspended solids, dissolved organics, salts, oils & greases, and naturally occurring radioactive material (NORM). To reduce the impacts of deep-well injection, comprehensive treatment of the wastewater has been proposed. Traditional treatment technologies explored include: coagulation and flocculation, granular media filtration, micro/ultra-filtration, reverse osmosis, forward osmosis, ion-exchange, activated carbon adsorption, distillation, and advanced oxidation processes. After analysis, a process was proposed using 3 treatment stages: (1) coagulation & flocculation and mixed-media rapid sand filtration to remove particulates and oil & greases, (2) forward osmosis desalination, and (3) advanced oxidation with ozone and hydrogen peroxide to degrade organic material. Design parameters were estimated for each stage to treat wastewater from 10 Marcellus Shale wells. An approximate cost analysis was also conducted to treat a loading of 10,000 m3/day, resulting in a total construction cost of $56,900,000, and a total operation and maintenance cost of $14,800,000.Environmental Engineerin