Oily Wastewater Treatment

Abstract

Oily wastewater is generally generated from the industries that are primarily engaged in the refining of crude oil, processing of food, transportation, and extraction. The hazardous nature of the oily wastewater poses serious threats to the environment and human health if it is disposed to the environment without proper treatment. Most of the countries around the world have their distinguished wastewater discharge standards. Therefore, efficient oily wastewater treatment is utterly important to improve the quality of the wastewater according to the wastewater discharge standards before releasing it into the water streams.In this chapter, we review the conventional and advanced technologies for the treatment of oily wastewater. The major points are the following: (1) There are several conventional oily wastewater treatments, such as flotation, coagulation, and biological treatments. Among these three methods, biological treatment is the least popular method for the oily wastewater treatment due to high difficulty in handling the diverse microbe behaviors under different environmental conditions. (2) Membrane technologies, such as microfiltration, ultrafiltration, nanofiltration, and reverse osmosis, are gaining significant attention due to high emulsion separation efficiency with the minimum use of chemicals, as well as the easy and low-cost operation. However, nanofiltration and reverse osmosis are not well received due to relatively low flux and high energy consumption. (3) Electrochemical treatment is arguably the most effective technique for oily wastewater treatment due to the energy saving process, robust performance, versatility, and simple process control kinetics. This treatment can achieve excellent removal of oil and grease, chemical oxygen demand, and turbidity of more than 90%. (4) The integration of various technologies has become an interest of studies for the improvement of oily wastewater treatment. These hybrid technologies have shown enhanced treatment performances than the treatment with a single technology.KeywordsOily wastewaterConventional wastewater treatmentMembrane filtrationElectrochemical treatmentHybrid technology