Bio-inspired wastewater treatment using agricultural wastes

点击翻译按钮获取中文摘要

Oily wastewater is an inevitable byproduct of many industries worldwide including petroleum refining, metalfinishing, food processing, edible oil production, paint manufacturing, and wood preservation industries. Asone of the largest global exporters of food and wood products with the second largest recoverable oilreservoirs, Canada has almost all the industries that can produce hazardous oily wastewater. Water usage in theoil sands industry, in particular, is the biggest concern. In the steam assisted gravity drainage (SAGD) forbitumen extraction steam is injected into the ground to decrease the viscosity of bitumen and to facilitate itsextraction. The mixture of water and bitumen then returns to the surface where the bitumen and water areseparated using a series of conventional gravity, flotation, and oil skimming processes to remove the bitumenand residual oil from the produced water. These techniques are not eco-friendly and suffer from inefficienttreatment, high capital and maintenance cost, generation of large volumes of sludge, and high energyconsumption. Hence, the focus of this research project is to develop a sustainable, cost-efficient andenvironmentally-friendly technique by utilizing natural organic adsorbents.Adsorbents originated from agricultural by-products are particularly advantageous due to their low-cost andhigh availability as starting materials. The high content of carbohydrate polymers in these materials increasestheir adsorption capacity through a series of chemical reactions between abundant hydroxyl groups ofcarbohydrate polymers and water contaminants. Wheat straw is one of the most available agricultural waste inCanada. Alberta alone yields 5.6 Mt of wheat, barley, oat and flax straw even after utilizing some for soilconservation and livestock feeding. Utilization of the waste wheat straw as an adsorbent for the treatment ofoily wastewaters will be an innovative technique since the system works on the principle of 'waste by waste',i.e., the system utilizes waste straw for treating the wastewater from which it generates treated water along withsaturated straw with oil which again is a waste but can be handled easily since it is biodegradable.