Challenges Treating Oily Wastewater

Oily wastewaters are generated in petroleum refining, food, metal finishing, auto service and other facilities. Fats, oils and greases (FOG’s) present in these wastewaters have to be removed before the water can be reused or discharged to surface water bodies. These oily waters are mainly in the form of oil-in-water (O/W) emulsions that pose a great problem in facilities attempting to stay in compliance with discharge limits. Treatment of oily wastewaters is performed by a variety of methods and the degree of oil removal depends mainly on the concentration and physical nature of the oil present and its droplet size. This paper looks at oil and grease removal treatment process alternatives and challenges.