Increases in economic development have led to a rise in water use and, consequently, wastewater production. Water and wastewater management has grown to be a major concern in recent years due to the precipitation decline. Environmental protection in general and, more especially, the quality of wastewater released into the environment without first being treated are the top concerns for municipal governments. It has, therefore, become necessary to treat and recycle this wastewater. Fuel oil is an energy source in many countries worldwide, and it is used to run steam boilers that power turbines and generate electricity. Drain electrostatic precipitators and water scrubbers are two of the techniques used to purify the fuel. These systems use water to clean these contaminants, leading to wastewater generation. Before being released into the receiving environment, this effluent, which is typically loaded with different contaminants, needs to be treated. Therefore, studying wastewater treatment from thermal power plants is critical and requires particular attention. Pollutants found in oil washing wastewater include hydrocarbons, oils and fats, phenols, ammonia, sulphides, and other organic compounds. The immune system may be significantly harmed by these contaminants. The marine environment that absorbs untreated effluent may likewise be greatly impacted. The maritime ecosystem may be significantly impacted by untreated fuel-washing water. Various processes have been implemented to treat this type of wastewater. However, most of these techniques are better suited to the specific treatment of this type of wastewater. This work aims to provide an overview of the situation of oil effluents on a national and international scale, highlighting their composition, their impact, and the different technologies used.