A system for separating petroleum from water that has been contaminated with petroleum products.
If rainwater finds its way into an underground gasoline storage tank, over a period of time the water forms a layer on the bottom of the tank and the gasoline floats above. Petroleum products are lighter than water and will, therefore, float on top of water. Because of this tendency of the two liquids to arrange themselves in layers, manufacturers of oil/water separators have been able to develop equipment that contaminated water can be fed into, and which creates an action resulting in relatively clean water coming out one port and petroleum product coming out the other.
Oil/water separators are relatively simple devices that look somewhat like an ordinary tank containing a series of baffle plates or coalescer plates. The contaminated water is introduced into one end of the tank and as it moves through the baffles, the oil-floating on top of the water-collects on these impediments. The oil floats to one level; the water to another level. By the time the oil/water mixture has made its way through the entire oil/water separator, a substantial portion of the two liquids has been separated. The oil typically collects in the oil/water separator until pumped out for sanitary disposal or further processing. The water typically flows out and is directed to an approved discharge point.
Oil/water separators are widely used at petroleum terminals and other locations where spills and overfills of product combine with surface water to create contamination.