Apparatus for superflocculating and thickening a sludge

An apparatus for superflocculating and thickening a sludge, which comprises

• (a) a cylindrical vessel having an upper part and a lower part,
• (b) an axially extending delivery conduit having an outlet in the upper third part of the vessel,
• (c) means for feeding a mixture of the sludge and of a flocculating agent to the delivery conduit whereby the mixture is delivered into the vessel through the delivery conduit outlet,
• (d) means for collecting liquid removed from the mixture delivered into the vessel and for discharging the removed liquid peripherally of the vessel at the upper part thereof,
• (e) a vertical rotary shaft extending through the vessel,
• (f) vanes mounted on the rotary shaft for rotation therewith,
• (g) counter-vanes arranged in the vessel to cooperate with the vanes,
• (1) the vanes and counter-vanes extending in substantially radial planes and being inclined with respect to each other, the inclinations of cooperating vanes and counter-vanes being in opposite directions, the vanes forming a discontinuous helix extending from the upper to the lower part of the vessel and the pitch of the helix diminishing towards the lower part of the vessel, and
• (h) a discharge conduit for the thickened sludge in the lower part of the vessel.