Oil Separation and Coalescence Separation: Fundamentals
Oil separation and coalescence separation are used to remove oils from industrial wastewater streams. Free oil is primarily separated from water by gravity. The separation performance depends significantly on the hydraulic retention time in the oil separator, as this determines how much time oil droplets have to rise to the water surface.
The design and operation of oil separators are governed by EN 858. The standard defines requirements for the design, performance and maintenance of systems used for the separation of light liquids such as mineral oils from wastewater.
Coalescence Separation for Unstable Emulsions
Lightly mechanically emulsified oils can form unstable emulsions that cannot be separated effectively by gravity alone. Coalescence separators are used for such applications.
The process is based on coalescence: small oil droplets combine to form larger droplets, which can then rise to the water surface more easily. This improves separation performance and enables finer oil droplets to be separated from the wastewater. Coalescence separation therefore complements conventional gravity-based oil separation.
OKO-aquaclean Systems: Design and Applications
The basic versions of OKO-aquaclean systems are designed as coalescence separators in accordance with EN 858. They are used in a wide range of applications, including mobile oil separation systems, groundwater remediation and metalworking fluid maintenance.
The systems combine robust construction with controlled separation performance and straightforward maintenance. Their modular design allows them to be integrated into existing wastewater treatment systems according to the specific application.
Please note: EN 858 does not cover the sole use of oil separators for applications involving washing temperatures above 60 °C, pressures above 60 bar or strongly emulsifying cleaning agents. In such cases, an Emulsion Breaking System (EBS) may be required downstream of the oil separator to further treat the emulsified oil.
