What could be best to separate Engine oil and water?

water is typically present in the emulsified phase creating a milkiness or fog in the oil, just like moist air on a cool day. When sufficient water exists, or when the oil has adequate demulsibility, free water will collect. Because water is typically heavier than oil, it settles below the oil, at the bottom of sumps and reservoirs. The point at which an oil contains the maximum amount of dissolved water is termed the saturation point. The saturation point is dependent on the oil’s temperature, age and additive composition. The higher the temperature, the higher the saturation point and hence more water held in solution, in the dissolved phase. This is the same as being able to dissolve more sugar in hot water, than in cold water. Similarly, the older the oil, the higher the level of water that can be dissolved. This is due to polar by-products of oxidation in the oil, which act as “hooks” holding on to the water molecules and keeping them in solution. Likewise, highly additized oils, like crankcase oils, have a higher saturation point than lightly additized oils like turbine oils, because the additives - many of which are polar - also hold the water in solution.