An oil-water separator is a device used for wastewater treatment that separates oil and suspended solids from water. It is commonly used in industries that generate oily wastewater, such as the petrochemical, chemical, and food processing industries, to remove pollutants before discharging the treated water into the environment.

The basic principle of an oil-water separator is to allow the mixture of oil and water to pass through a series of baffles or plates that cause the oil to rise to the surface, where it can be skimmed off and collected. The remaining water is then passed through a filter or membrane to remove any remaining suspended solids and contaminants.

Oil-water separators can be designed to handle different volumes of wastewater, depending on the needs of the industry. They can be installed above or below ground, and can be constructed from a variety of materials, including steel, fiberglass, and concrete.

In addition to their use in industrial applications, oil-water separators are also used in stormwater management systems to prevent oil and other pollutants from entering waterways during heavy rainfall events.