Patent ID: 7524415

Claim:
An effluent purifying plant with centralized structure comprising, on a vertical axis, a homogenizing vessel ( 1 ) receiving the effluent with the addition of a coagulating or flocculating agent, a settling vessel ( 2 ) beneath the homogenizing vessel ( 1 ), a flocculating vat ( 3 ) comprising a frustoconical upper portion ( 31 ) extended by a lower portion, which vat is placed inside the settling vessel ( 2 ) and in which sludge flakes form, a pipe ( 6 ) arranged in the axis (ZZ), leading downwards, connecting the homogenizing vessel ( 1 ) to the lower part of the flocculating vat ( 3 ) through which the effluent passes from bottom to top and is clarified in contact with the sludge flakes, the pipe ( 6 ) comprising an upper tube, one end of which opens into the homogenizing vessel and the other end of which opens into a lower tube of larger diameter than that of the upper tube, the lower end thereof opening into the lower part of the flocculation vat, the lower portion of the settling vessel having a frustoconical portion forming the sludge vat ( 4 ) which receives the sludge overflowing from the flocculating vat ( 3 ), an annular vessel surrounding the settling vessel and receiving the filtered water by overflow from the settling vessel ( 2 ), characterized in that the homogenizing vessel ( 1 ) has a tangential intake ( 91 ) for the effluent, the inlet ( 611 ) and the outlet ( 612 ) of the upper tube ( 61 ) include a helical guide ( 613 , 614 ) for setting the effluent in rotation, the lower tube ( 62 ) of larger diameter than that of the upper tube ( 61 ) is terminated by an outlet in the form of an upside-down cone ( 622 ) with reduced cross-section ( 621 ), the lower portion ( 31 ) of the flocculating vat ( 3 ) is frustoconical, with an apex angle smaller than that of its upper portion ( 32 ), the lower portion ( 31 ) being parallel to the cone of the outlet of the lower tube ( 62 ), and at least one anti-backflow cone ( 7 , 8 ) surrounds the pipe ( 6 ) in the settling vessel ( 2 ).