an adjustable overflow lip 4 to skim off the top surface layer into chamber 2 which has an arched roof lying wholely lower than lip 4, oil being discharged through outlets 13, possibly by a suction pump, to a further settling stage (not disclosed) and water being discharged by pump 14....
If its API gravity is greater than 10 °API, it is lighter and floats on water; if less than 10 °API, it is heavier and sinks. So the heavier the oil the fewer barrels per ton you get. From the EIA: Barrels of Crude Oil per Metric Ton by country. East Timor 8.343 Algeria ...
Oil floats to the surface of water and is separated by the oil separating trap. At the same time, the concentrations of pollutants in wastewater is reduced to a value where it is possible to perform physical and chemical treatment in the radial settling basins and flotators. Physicochemical ...