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. The device for carrying out said method comprises a submersion body of submersion depth first increasing downstream then decreasing, provided with opening serving as hopper to produce suction effect, on bottom in range of greatest submersion cross-section or behind latter, with adjustable spillway on front end on side of inflow, whereas with baffle plate controlling direction of flow and defining cross-section in inner space of submersion body, and with a flow-free zone for collecting the impurities separated.