A lamellar separator for clarification of aqueous influents comprising a primary clarification section provided with inclined co-current lamellas fed by the said aqueous influents at the upper ends of the said lamellas and discharging streams of concentrated solids and streams of clarified liquid at the lower end of the said lamellas, and an interception section attached to and being in hydraulic communication with the said primary clarification section at the lower ends of the said lamellas, the said interception section housing at least one interception means, whereby the said streams of concentrated solids are combined into a flow of concentrated solids and the said streams of clarified liquid are combined into a flow of clarified liquid, and the said flow of concentrated solids and the said flow of clarified liquid are evacuated from the said lamellar separator without intermixing.