North Dakota’s oil boom is aided by a new technology, fracking. But this technology implies large amounts of wastewater. The methods of dealing with this wastewater are now an issue. Currently, North Dakota locks it into deep injection wells in the Bakken formation. With the development of membrane technologies to treat wastewater, it may be feasible to treat the wastewater and reuse it. This study uses a mathematical programming model to minimize the total cost of dealing with wastewater using three methods - deep well injection, on-site treatment, and off-site treatment. The model results show it is cost-effective to use on-site and large capacity off-site treatment to treat the 20% of the wastewater that flows back within the first 30-60 days after a well is drilled.

This analysis focused primarily on three main treatment methods which were re-use, recycle, and disposal wells. The re-use treatment option is when wastewater is mixed with source water in order to meet fracturing water requirements. With this option, the hope is that the wastewater for re-use will require little or no treatment at all. The second treatment option is the recycle option. This option provides high quality water for re-use or discharge to the environment using a recycling technology. The credibility of this option is heavily dependent on its ability to recycle almost all of the wastewater with little or none left for disposal or treatment. The third option is well disposal. This entails disposing all of the wastewater into a deep formation. The software used for building the model is called @Risk. The model’s costs were estimates from recent research to capture the risks and uncertainties associated with wastewater disposal. The model revealed that re-use option remains the most cost effective treatment method to reduce overall water management cost in the Marcellus. The re-use option is most viable when a hydraulic fracturing schedule is continuous (no significant storage requirement) and infrastructure is available to transport wastewater from one fracturing operation to the other. The recycle option is the second most viable disposal option. This option is most effective when the hydraulic fracturing schedule is staggered in both time and distance because distilled water from recycling facilities can be easily discharged into the environment or stored. The most unfavorable option for wastewater management at the Marcellus is the well disposal option due to the high cost of trucking wastewater to disposal wells in neighboring states or counties. It also requires the highest usage of fresh water. A well disposal option can be favorable at the onset of a hydraulic fracturing schedule when there are low levels of infrastructure, hydraulic fracturing programs are not continuous or localized in proximity, and the volume of wastewater does not exceed the capacity for injection. In this case, disposal wells can be more favorable than recycle or re-use if they are in close proximity to drilling sites. / text

Deep injection wells (DIW) in Florida are regulated by the U.S. Environmental Protection Agency (USEPA) and the state of Florida through the Underground Injection Control regulations contained within the Safe Drinking Water Act. Underground injection is defined as the injection of hazardous waste, nonhazardous waste, or municipal waste below the lowermost formation containing an underground source of drinking water within one-quarter mile of the wellbore. Municipalities in Florida have been using underground injection as an alternative to surface disposal of treated domestic wastewater for nearly 40 years. The research involved collecting data as of September, 2007 on all the Class I DIWs in the state of Florida and evaluating the differences between them. The analysis found regional differences in deep well practice and canonical correlation analyses concluded that depth below the USDW is the most significant factor to prevent upward migration of the injected fluid. / by Jie Gao. / Thesis (M.S.C.S.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.