Bio-inspired wastewater treatment using agricultural wastes

含油废水是世界范围内许多工业的不可避免的副产品，包括石油精炼、金属精加工、食品加工、食用油生产、油漆制造和木材防腐工业。作为全球最大的食品和木制品出口国之一，加拿大拥有第二大可采油藏，几乎所有的工业都可能产生危险的含油废水。尤其是油砂行业的用水量是最大的问题。蒸汽辅助重力泄油法（SAGD）是将蒸汽注入地下以降低沥青的粘度，促进沥青的开采。然后，水和沥青的混合物返回到地面，在那里使用一系列常规重力、浮选和撇油工艺将沥青和水分离，以从采出水中除去沥青和残余油。这些技术不是生态友好的，并且具有处理效率低、资金和维护成本高、产生大量污泥和高能耗的缺点。因此，本研究的重点是利用天然有机吸附剂开发一种可持续的、经济有效的、环境友好的技术，其中来自农副产品的吸附剂由于其低成本和高可用性而具有特别的优势。这些材料中高含量的碳水化合物聚合物通过碳水化合物聚合物中丰富的羟基与水污染物之间的一系列化学反应来增加其吸附能力。小麦秸秆是加拿大最有效的农业废弃物之一。仅阿尔伯塔一省就生产了560万吨小麦、大麦、燕麦和亚麻秸秆，即使将其中一些用于土壤保护和牲畜饲养。利用废弃小麦秸秆作为吸附剂处理生活污水将是一项创新技术，因为该系统的工作原理是“废物对废物”，即，该系统利用废秸秆来处理废水，从该废水中产生处理水，沿着的是具有油的饱和秸秆，所述油也是废物，但是由于其是可生物降解的，所以可以容易地处理。

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.