Abstract: The invention relates to an apparatus for separating solids from a liquid, comprising at least one reservoir or basin (12) for receiving solid-loaded liquid and having at least one inflow (1, 27, 101) and/or outflow (2, 111); and at least one separation device (9, 16, 25, 55, 56, 62, 63, 108) arranged in the reservoir or basin (12) for the solids, wherein the separation device has at least one separation surface, which is at least adjustable between a separation position (?) and a cleaning position (?). According to the invention, the apparatus comprises a control device (57, 58; 64, 66; 106) coupled or connected to the separation device (9, 16, 25, 55, 56, 62, 63, 108) and being operable by the liquid supplied into the reservoir or the basin (12), by means of which the position of the at least one separation surface can be changed or varied. Further a separation device (9) having at least one separation surface is provided, which comprises a surface coating and/or an at least partially structured surface.