An apparatus for removing sludge from a reservoir of liquid. A downwardly opening enclosure is positioned atop the floor of a reservoir with the enclosure having inlets for sludge and liquid to flow into the cavity of the enclosure. Gas emitters on the opposite edge portions of the enclosure assist the flow of sludge and liquid into the cavity which is slanted upwardly towards an outlet having a lift pump for pulling the sludge and liquid from the enclosure. An optional additional passage leading from the cavity to a holder beneath the enclosure receives heavy sludge falling there through.