conduits 13 are positioned as shown in fig1 to provide a generally chevron shape whereby the supply conduits 13 extend inwardly and rearwardly relative to the direction of travel of the sludge toward the discharge opening 11 in fig4 and 5 we show a circular settling basin 10a which carries radially extending support arms 26 that are attached to a sludge removal conduit 27 having a suitable screen 28 at the lower end thereof to prevent the passage of large particles such as rocks or the like into the conduit 27 the sludge removal conduit 27 is operatively connected to a suitable pump not shown whereby the sludge may be removed also the settling basin 10a may be provided with a conventional fixed withdrawal conduit 12a adjacent the bottom center thereof as shown the screen 28 also prevents the passage of large particles into the conduit 12a mounted within the basin 10a and secured to the radially extending arms 26 are concentric liquid supply conduits 29 31 and 32 which are connected to supply conduits 33 34 and 36 respectively suitable control valves 37 38 and 39 are provided in the conduits 33 34 and 36 respectively whereby the liquid may be introduced sequentially to continuously or intermittently move the sludge toward the sludge removal conduits 12a and 27 suitable jet nozzles 23 a which are identical to the jet nozzles 23 are provided in each of the supply conduits 29.