In the Ultrafiltration (UF) process, wastewater containing emulsified oils is pumped through a membrane unit. Water and some dissolved low molecular weight materials pass through the membrane pores and exit the system as permeate. Emulsified oil and any suspended solids are retained by the membrane and remain in the wastewater feed. The emulsified oil is concentrated in this manner up to approximately 60% oil and solids.

What is Emulsified Oil?
There are two forms of oil that we find in wastewater. Free Oil is oil that will separate naturally and float to the surface. Emulsified Oil is oil that is held in suspension by a chemical substance (Detergents - Surfactants) or electrical energy. Free Oil will normally separate by gravity and float to the surface in approximately 30 minutes. Emulsified Oil is held in a molecular structure called a micelle and will not separate on its own.