In Alberta, the oil-sands industry plays an important role in the local economy. However, the industry consumes a large amount of water, which is not economical. Significant capital and operating costs have been invested by the oil industries in the treatment of this contaminated water every year. Our objective is to develop new treatment solutions for the removal of contaminants, particularly silica but also organics and some hardness, using electrocoagulation to enable increased water recycling while decreasing capital and operating costs. The treatment of oil sands produced water by electrocoagulation is explored and investigated in this research. The major contaminant targeted is dissolved silica, which is the cause of the scaling problem in the steam generators in the oil-sands production process. Electrocoagulation is found to be very efficient to remove dissolved Si from approximately 60 mg/L to less than 5 mg/L, corresponding to greater than 90% Si removal. In addition, removal of 90% of the calcium present, and 60% of the magnesium could be achieved. The effect of operating parameters on electrocoagulation performance were evaluated, including the anode materials (aluminum and iron), current density, inter-electrode distance, and dissolved oxygen. Current density of 8 mA/cm2 was found to be the most efficient and also economical compared to 4 and 16 mA/cm2. Increasing the inter-electrode distance results in lower contaminant removal and higher energy consumption. Dissolved oxygen is important for enhancement in Fe-EC. The current efficiencies for metal dissolution obtained with aluminum and iron electrodes materials, as well as their electrochemical behavior, was investigated. Fe-EC had current efficiencies between 90-95%, while Al-EC showed larger than 100% current efficiencies. Besides operating parameters, different electrochemical reactor designs were also tested. Experiments were carried out in system and flow recirculation systems. A novel concept of utilizing an oscillating anode in EC was tested with both batch and recirculating flow. The combination of a batch recirculating flow reactor and anode oscillation showed the best contaminant removal performance. Investigation of the viability of EC for oil sands industry applications such as oil-sands produced water and boiler blowdown water samples have also been carried out, and the Si removal efficiency is also promising compared to the synthetic produced water. The operating cost of our EC treatments is also in the lower range compared to the general EC operating costs.