Emulsified oil in wastewater

Emulsified oil may be contained in the wastewater from the desalter unit of the refinery. The emulsified oil in the wastewater is not easy to separate. When the emulsified oil is pumped into the oil tank and then pumped into the refinery, the emulsified oil will affect the relevant units indefinitely.Any ideas or tips to stop the emulsified oil in wastewater?