Fuel and lubricating oil leaks produce an oily wastewater that creates an environmental problem for industries. Dissolved air flotation (DAF) has been successfully employed for the separation of oily contaminants. Collectors constitute an auxiliary tool in the DAF process that enhances the separation efficiency by facilitating the adhesion of the contaminant particles. The use of biosurfactants as collectors is a promising technology in flotation processes, as these biomolecules are biodegradable and non-toxic. In the present study, a biosurfactant was produced from the bacteria Pseudomonas aeruginosa UCP 0992 cultivated in 0.5% corn steep liquor and 4.0% vegetable oil residue in a bioreactor at 225 rpm for 120 h, resulting in a surface tension of 26.5 mN/m and a yield of 26 g/L. The biosurfactant demonstrated stability when exposed to different temperatures, heating times, pH values and salt and was characterised as a glycolipid with a critical micelle concentration of 600 mg/L. A central composite rotatable design was used to evaluate the effect of the crude biosurfactant added to a laboratory DAF prototype on the removal efficiency of motor oil. The isolated and formulated forms of the biosurfactant were also tested in the prototype after the optimisation of the operational conditions. The results demonstrated that all forms of the biosurfactant increased the oil separation efficiency of the DAF process by 65 to 95%. In conclusion, the use of biosurfactants is a promising alternative as an auxiliary tool in flotation processes for the treatment of oily waters generated by industrial activities.

中文翻译：

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在浮选系统中使用低成本生物表面活性剂处理含油废水。

燃油和润滑油的泄漏会产生含油废水，给工业造成环境问题。溶解气浮法（DAF）已成功用于分离油性污染物。收集器是DAF工艺中的辅助工具，可通过促进污染物颗粒的粘附来提高分离效率。在浮选过程中，使用生物表面活性剂作为捕收剂是一种很有前途的技术，因为这些生物分子是可生物降解的且无毒的。在本研究中，由铜绿假单胞菌细菌生产了一种生物表面活性剂。UCP 0992在生物反应器中的0.5％玉米浆和4.0％植物油残渣中以225 rpm的速度培养120 h，表面张力为26.5 mN / m，产量为26 g / L。当暴露于不同的温度，加热时间，pH值和盐时，该生物表面活性剂表现出稳定性，其特征是糖脂的临界胶束浓度为600 mg / L。中央复合可旋转设计用于评估添加到实验室DAF原型中的粗生物表面活性剂对机油去除效率的影响。优化操作条件后，还对原型中的生物表面活性剂的分离和配制形式进行了测试。结果表明，所有形式的生物表面活性剂均可将DAF工艺的油分离效率提高65％至95％。结论，