Abstract: The invention relates to a device for purifying waste water, comprising a reservoir (2), supply means (3) for the waste water flowing out into the reservoir, means for maintaining a pre-determined fluid level (11) in the upper part of the reservoir and draining means (12) for draining purified water from the reservoir. Said reservoir forms part of a cycle of microbe supporting elements (8) that have a lower density than 1, and comprising means (15) for removing microbe supporting elements from the reservoir operative above the pre-determined level, cleaning means (17) for removing sludge from the supporting elements, and re-introducing means (20) flowing out into the lower part of the reservoir for re-introducing the cleaned microbe supporting elements.

Abstract: A separator comprises a frame supporting a closed cylindrical drum, a motor for rotating the drum about a central, longitudinal axis, an inlet through which a liquid from which constituents are to be separated is introduced into the drum, and an outlet through which relatively clean liquid is dischargeable from the drum. During the separating process, centrifugal force causes a layer of the heavier constituents to collect on the interior surface of the drum, displacing the relatively clean liquid into an annular layer situated concentrically with and between the constituent layer and the entering volume of liquid, such that the contents of the annular layer is separately dischargeable from the drum in a continuous manner.