Abstract: In a rectangular primary sedimentation tank having a transverse trough for sludge collection, a sludge shovel apparatus is provided for efficient removal of sedimentation. In one embodiment, a reciprocative trolley assembly, hoist linkage and latching means operate together to carry a sludge shovel in a scooping position from a drop end of the trough toward a sludge withdrawal end, to vertically lift the sludge shovel above the sedimentation level, to return the sludge shovel to its starting end and to drop it for continued scooping operation. Continuous and efficient sludge removal is thereby effected with minimal disturbance of the remaining sludge during the raising and lowering of the sludge shovel.