Clarifier for liquids laden with suspended matter, comprising: an outer, first, cylindrical tank (4), a central, second, cylindrical tank (1) for collecting the filtered liquid, roughly coaxial with the first; an intermediate tank (2), formed between the outer tank (4) and the central tank (1) and roughly coaxial therewith; structure (19) for the feed of pressurized backwash liquid to the filter medium (14); a hood (26) for recovering the washing liquid after it has passed through the filter medium (14); a rotary bridge (8) which can rotate above the collection of cylindrical tanks (1, 2, 4), a compartment for introducing the liquid that is to be clarified, this compartment being positioned between the intermediate tank (2) and the central tank (1) and feeding the outer tank (4) centrally with liquid laden with suspended matter, the said compartment being itself fed with liquid that is to be clarified from the outside via a number of inlets (3).