An apparatus for separating floating and non-floating particulates from drain water wherein the apparatus includes a first chamber for collecting non-floating particulates, a second chamber for collecting floating particulates, and a third chamber through which treated drain water can be discharged from the apparatus. An inlet pipe for introducing drain water into the first chamber is provided tangential to the first chamber to provide a vortex flow of drain water into the first chamber, and an outlet pipe providing flow of drain water from the first chamber to the second chamber has an inlet at the vortex of drain water flow in the first chamber.