NOVELTY - Wastewater is purified in a device by, pumping water using water pump (20) above distribution disc through a filter head (21) with a filter (22), letting out filtered water through outlet tube, transferring water in a reject conduit (23) rejected from the filter back to the distribution tube, and adding flocculation agent to the unfiltered water before reaching the distribution tube. The water below the distribution disc is biologically treated with bacteria in a bioreactor and returned to the distribution tube. The bacteria are carried on a carrier material, i.e. zeolite.    USE - The method is useful in purifying wastewater in a device.    ADVANTAGE - The method employs a flocculation agent or a precipitation agent to the wastewater to improve the purification of the wastewater.    DETAILED DESCRIPTION - Purification of wastewater in a device comprising a cup-shaped vessel (5), which has a wastewater inlet tube (7) for the water at a certain level and an outlet tube (8) at a lower level than the inlet tube; and a horizontal distribution disc (2), which vertically divides the vessel, having at least one opening and is provided with a substantially vertical distribution tube (3) for receiving the water from the inlet tube and for liquid contact between vessel portions above and below the distribution disc, comprises pumping water using a water pump above the distribution disc through a filter head with a filter, letting out the filtered water through the outlet tube, transferring water in a reject conduit rejected from the filter back to the distribution tube, and adding flocculation agent to the unfiltered water before reaching the distribution tube. The water below the distribution disc is biologically treated with bacteria in a bioreactor and returned to the distribution tube. The bacteria are carried on a carrier material, i.e. zeolite. An INDEPENDENT CLAIM is included for a wastewater purifying device as above.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic cross section of a wastewater purification device.    Distribution disc (2)    Distribution tube (3)    Cup-shaped vessel (5)    Wastewater inlet tube (7)    Outlet tube (8)    Water pump (20)    Filter head (21)    Filter (22)    Reject conduit (23)