The Oil Sands Region of North-Eastern Alberta, Athabasca, has been home to the commercial production of bitumen since the late 1960's. Mining is one of the most common techniques used for oil extraction in this region. Bitumen is then extracted from the oil sand using hot water. The wastewater obtained from treating mined sand has high levels of naphthenic acids as well as calcium ions (Ca2+) and is not suitable for release to the environment or for recycling back into the extraction process. This water has been retained in storage areas for years and is called consolidated tailings (CT) release water. If the CT release water can be processed to remove the naphthenic acid and calcium components, it can either be recycled back to the extraction process, which will reduce the demand for fresh makeup water from the Athabasca River, or discharged directly to the environment. Chemical Engineering students from University of Waterloo conducted a design project in their 4th year of study to review possible methods for treating the tailings water, and estimated the expected cost to treat 10 years of CT release water.
This case study introduces students to various methods for removing contaminants from industrial wastewater. Students learn about the design of reactors and vessels, and the development of their design equations. By the end of the case study, students should be able to identify suitable processes for wastewater treatment, and be able to analyze series and parallel vessel arrangements. Students will also gain experience with estimating the cost of industrial processes.