Water Resources Research Act Program

Details for Project ID 2015ND296B

Glutaraldehyde Removal from Flowback and Produced Water Using Photolysis

Institute: North Dakota
Year Established: 2015 Start Date: 2015-03-01 End Date: 2016-02-29
Total Federal Funds: $6,132 Total Non-Federal Funds: $12,265

Principal Investigators: Khan Eakalak, Sivaguru Jayaraman

Project Summary: In unconventional oil and gas extraction, hydraulic fracturing technology has been applied to ensure high and prolonged production of oil and gas from shale deposits. This technology induces cracking network in low-permeability shale to allow trapped oil and/or gas flow to the production wells by injection of hydraulic fracturing fluid at extremely high pressure and flow rate. Primarily, due to this recently improved technique, North Dakota right now is the second largest crude oil producing state in the United States, with 314 million barrels of oil produced in 2013. Currently, oil withdrawal from the Bakken shale, which requires hydraulic fracturing, accounts for 90% of North Dakotas oil production.In addition to the additives found in fracturing fluids, contaminants in flowback water also come from water in shale and dissolution of shale, which are dissolved and suspended salts and metals, dissolved and non-aqueous hydrocarbons, and in some locations, naturally occurring radioactive materials. The water that flows to the surface after flowback water until the end of the life of well is called produced water. Produced water is naturally occurring water in shale. This water tends to have more mineral and hydrocarbon than flowback water.Biocides are considered as one of the most harmful contaminants in flowback water. Glutaraldehyde (GA), the most common biocide used in hydraulic fracturing fluid, accounts for 80% of all shale fracturing. It is also used periodically to keep the number of bacterial cells low in the production well.In addition to its toxicity, the other obvious issue with GA in flowback and produced water is the restriction of biological activities in the wastewater making biological treatment a non-viable alternative. Thus, removing GA from flowback and produced water would be beneficial for both environment and wastewater recyclability and disposal. The specific objectives of this research are: 1. Determine GA removal efficiency and kinetics by photodegradation; 2. Elucidate removal mechanism, pathways, intermediates, by-products, and end-products of GA photodegradation; and 3. Identify optimal operating conditions for photodegradation of GA. The result from the project will show for the first time of the actual concentration of GA in flowback and produced water which is important to accurately evaluate the impact of flowback and produced water to the environment. The project will deliver a cost effective treatment scheme for the reuse and disposal of the flowback and produced water which in turn will benefit the oil and gas production industry in cost saving on fracturing water and the environment in eliminating or minimizing pollutants discharge.