Abstract: An apparatus for separating supernatant pollutant, such as oil, from a liquid, such as water is disclosed. The apparatus comprises a receiving tank and a separating tank. The receiving tank has a wall dividing the tank into a first vessel receiving the liquid mixture and having a self-adjusting weir, and a second vessel. The separating tank has a first receptacle separated from the first vessel by a partition along which the self-adjusting weir is located, and a second receptacle connected to the first receptacle. The first receptacle has an outlet for draining the supernatant, while the second receptacle and second vessel have outlets for draining the cleaned liquid.

Abstract: Separation of impure surface water layer, separation of mixture of impurities and water and method for implementation of discharging impurities separated, according to which local water level lowering required for flowing impure surface water layer through overflow spillway is performed in conformity with the Bernoulli formula by suction effect produced and maintained by increasing flow rate, while separation taking place in the same step is carried out by the transient decrease of flow rate, then by change of direction. By turbulent-free inflow without decrease of rate really excellent scraping efficiency can be achieved.