AFL has developed coalescing media to upgrade existing gravity separators used in treating oily wastewater. The principal function of the pack is to provide a coalescing surface on which minute oil globules can agglomerate. The coalesced oil then rises to the surface to be skimmed.
Coalescing media makes possible the attainment of one of two goals-or a compromise between them:
The vertically-postioned tubes, made of polypropylene, have oleophilic (oil-attracting) properties. Small, suspended particles of oil agglomerate on the stranded surface of the tube waiting for more oil to increase their size as well as buoyancy. Once sufficiently large they break free from the tube and rise quickly to the surface thru it’s center.
The media provides up to five times more coalescing surface than a plate pack. The extra surface gives oil globules more area on which to collect.
The vertical orientation of the tubes contributes to a more efficient separation. In a plate pack the rising oil must move against the flow of the influent. With a tube pack, however, the oil is free to travel a clear upward path to the surface.
The tubes remove oil globules down to the 20-micron range; this contrasts with the removal of 150 micron globules by gravity separators constructed on API dimensional criteria. In AFL coalescing separators the tubes typically produce effluents with an oil content of less than 10 mg/ltr.