The HELI-SEP® is a single vertical cylindrical vessel design that utilizes fluid velocity reduction, differential specific gravity and coalescences to separate nonsoluble oil, solids and entrained air from oily water. Three different actions occur with in this one vessel to provide the efficient removal or reduction of oil content to 15 PPM or less at flow rates up to 44 gallon per minute. Oily water is pulled into the HELI-SEP® by the integral pump. The water flows through a permanent "honeycomb" matrix featuring a large amount of surface for the oil to make contact with and coalesce. As the droplet increase in size they detach from the surface of the matrix and float to the top of the vessel. The water is then pulled through an oleophillic media where fine oil droplet are captured and retained until the oil discharge cycle. When sufficient oil accumulates the unit enters into an oil discharge and backwash cycle. During this process the oil is flushed from the media and discharged from the unit.