There are three general levels of wastewater treatment: Primary, Secondary, and Tertiary.Primary: the first level of treatment where coarse suspended solids, mixtures, and some mechanical emulsions are separated from water.Secondary: the next level of treatment which removes the remaining mechanical emulsions, chemical emulsions, and organic matter in solution using chemical and biochemical processes.Tertiary: the final level of treatment which removes any impurities remaining in the effluent from the previous primary and/or secondary treatment process. This level usually requires the use of filter media or membrane filters to remove small concentrations of matter, or trace concentrations of metals, salts, or colloids.The Hydrasep oil water separator is a primary treatment device.