Oil Separation

Oil Separation

Streams of oily wastewater are frequent within industry, however, that does not mean we should be complacent about them.

Common sources of contamination are petroleum derivatives and fats from vegetable and meet processing.

Dedicated solutions have been developed by FARAN Process and Energy Engineering Company employing the following technologies:

1. API Pits, (static gravity separator)

These rely heavily on gravity and perhaps represent the original, simplest and lowest cost of separating certain amounts of oils/solids prior to discharge to the sewer.

The method of operation is that effluent/contaminated water enters the vessel (tank/compartments(s)) where it must sit undisturbed for a prolonged period of time, oil eventually floats to the top of the holding tank.

2. Parallel/Coalescing Plate Separators. (CPI Separator)   

These separators arguable represent second-generation systems for the waste/effluent treatment of oil/ solids contaminated water prior to discharge to sewer.

They consist of a chamber containing; a pack of narrowly separated paralleled plates stacked one above the other (usually fiberglass or stainless steel plates) usually with the plates inclined so as not to impede flow. The method of operation is that effluent/waste water flow smoothly between the plates with a minimum of turbulence/disturbance. Oil coalesces or ‘sticks’ on the surface of the plate above and travels to the opposite opening between the plates.

The coalesced oil then migrates to the bulk of oil at the top of the chamber.

By comparison with settling tanks, oil may have to rise many centimeters to coalesce whereas in a plate pack coalescence occurs between the plates which may be only a couple of centimeters. Some newer designed plate separators are even more compact.

3. Hydrocyclone Oil Separator.

These separators are compact, (depending on the application) and are designed as a vertical cylinder/cone with oily effluent/waste entering at the top via a positive pressure pump. “The flow is directed into a vortex without disrupting the reverse flowing core. As the flow is forced down the liner it takes up a helical form along the inner walls and (accelerates) creating the strong centrifugal forces that promote rapid separation (of oil from water). The denser water moves to the walls of the hydrocyclone and is removed at the downstream clean water outlet. Oil is drawn into the low pressure core and by applying back pressure to the treated water outlet it flows back up the hydrocyclone to be removed at the upstream outlet orifice”.

4. Dissolved air Floatation (DAF)

The equipment incorporates many superior designs, both mechanical and operational. The units are used in applications where the specific gravity of the solids or contaminants is very close to or less than 1.0.

Within the retention tank, air is dissolved into the liquid under pressure. The liquid level within the retention tank is monitored by level controls and maintained by air release valve. The air-saturated liquid shall then exit the retention tank and be directed toward the back pressure control valve in the skimmer tank.