Treatment of pulp mill and oil sands industrial wastewaters by the partial spray freezing process.

The spray freezing process, a natural freezing technology, was used to treat pulp mill effluent and oil sands tailings pond water. The wastewaters froze partially or completely (i.e. with or without runoff generation) during the spraying operation. Greater than 60% impurity reduction in the spray ice was obtained when 30% of the total volume of the sprayed water was released as runoff. Organic and inorganic contaminants were rejected with different efficiencies. The impurities were uniformly distributed within the ice columns when the spray ice was produced without generating any runoff. While a significant increase in impurity concentration was observed at the bottom of the ice formed with runoff production. The spray freezing process is an effective and economically feasible technique for wastewater treatment in cold regions. To achieve higher impurity removal efficiency, the wastewater should be only partially frozen during spray ice production.

Color and chlorinated organics removal from pulp mills wastewater using activated petroleum coke.

Delayed petroleum coke, a waste by-product from the oil sand industry, was utilized in the production of activated carbon. The activated carbon was then evaluated for color and chlorinated organics reduction from pulp mill wastewater. The activation of the petroleum coke was evaluated using a fixed bed reactor involving carbonization and activation steps at temperature of 850 degrees C and using steam as the activation medium. The activation results showed that the maximum surface area of the activated coke was achieved at an activation period of 4 h. The maximum surface area occurred at burnoff and water efficiency of 48.5 and 54.3%, respectively. Increasing the activation period to 6 h resulted in a decrease in the surface area. Methylene blue adsorption results indicated that the activation process was successful. Methylene blue adsorbed per 100 g of applied activated coke was 10 times higher than that adsorbed by raw petroleum coke. Adsorption equilibrium results of the bleached wastewater and the activated coke showed that significant color, COD, DOC and AOX removal (> 90%) was achieved when the activated coke dose exceeded 15,000 mg/L. Adsorption isotherms, in terms of COD, DOC, UV and color were developed based on the batch equilibrium data. Based on these isotherms, the amount of activated coke required to achieve certain removal of color and AOX can be predicted. The utilization of the petroleum coke for the production of activated carbon can provide an excellent disposal option for the oil sand industry at the same time would provide a cheap and valuable activated carbon.