Utilizing Petroleum Coke for Hydraulic Fracturing Flowback and Produced Water Treatment - Targeting Dissolved Organics and Iron Removal

Responsible hydraulic fracturing is important for the future of Canada's oil and gas sector. Hydraulic fracturing operations use significant amounts of water. The flowback and produced water from hydraulic fracturing operations contain toxic chemicals and is stored on site. Alberta Energy Regulator records hundreds of surface spills of flowback and produced water per year. Nevertheless, to promote water reuse during hydraulic fracturing operations and reduce costs, industry uses fit-for-purpose water treatment methods to treat the flowback and produced water, targeting suspended solids and dissolved solids. In addition, the recent interest in the lithium content in hydraulic fracturing flowback and produced water has stimulated direct lithium extraction technology development across Canada. However, most of these technologies require a certain degree of organic removal. Traditional water treatment technologies are costly, and as such, further development in low-cost water treatment techniques is crucial to treat and reuse flowback and produced water. In this study, we utilized waste materials (i.e., petroleum coke) from the oil sands industry for hydraulic fracturing flowback and produced water treatment by employing an in-house coke activation method. Flowback and produced water samples from different locations in the Western Canadian Sedimentary Basin were analyzed and compared using a suite of analytical techniques. Dissolved organics were analyzed by high-resolution mass spectrometry using nontargeted analysis methods. The organic and iron removal efficiencies of different activated carbon products were compared. Results indicate that the surface area of coke is the primary factor influencing its adsorption capacity for dissolved organics; however, it does not significantly impact the efficiency of iron removal. Overall, this study demonstrated the potential of using petroleum coke for treating flowback and produced water, laying grounds for development of low-cost treatment technologies.