NOVELTY - A sludge-disposal apparatus is provided with an ultrasonic sludge-disposal unit (11) to irradiate ultrasonic wave to sludge. The apparatus has a rod-shaped ultrasonic oscillator (13), a cylindrical screen (14), a to-be-processed-sludge inflow path (16) and a non-processed-sludge outflow path (17) connected to an ultrasonic process chamber (15), and a processed-sludge outflow path (19) connected to a process-sludge outflow chamber. The sludge-disposal unit consists of the ultrasonic oscillator provided in a processing container (12).    USE - Apparatus for disposing sludge, such as digested sludge extracted out from methane-fermentation tank, livestock excrement, sewage sludge, purification-tank sludge containing organic refuse, pruned branch, used paper, litter, foodstuffs residue, etc. (all claimed), and sludge generated by water-treatment processes.    ADVANTAGE - The sludge-disposal apparatus enables efficient processing of surplus sludge and improves methane-fermentation efficiency.    DETAILED DESCRIPTION - A sludge-disposal apparatus is provided with an ultrasonic sludge-disposal unit (11) to irradiate ultrasonic wave to sludge. The apparatus has a rod-shaped ultrasonic oscillator (13), a cylindrical screen (14), a to-be-processed-sludge inflow path (16) and a non-processed-sludge outflow path (17) connected to an ultrasonic process chamber (15), and a processed-sludge outflow path (19) connected to a process-sludge outflow chamber. The sludge-disposal unit consists of the ultrasonic oscillator provided in a processing container (12). The sludge treated with ultrasonic waves when flown into the ultrasonic process chamber permeates the cylindrical screen to the processed-sludge outflow chamber (18). The cylindrical screen surrounds the ultrasonic oscillator and divides the processing container into ultrasonic process chamber of inner circumference side and processed-sludge outflow chamber of peripheral side. The screen is a porous material of wedge wire screen, punched metal, network structure, or texture structure, containing metal, ceramics or plastic.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of the sludge-disposal apparatus.    Ultrasonic sludge-disposal unit (11)    Processing container (12)    Ultrasonic oscillator (13)    Screen (14)    Ultrasonic process chamber (15)    To-be-processed-sludge inflow path (16)    Non-processed-sludge outflow path (17)    Processed-sludge outflow chamber (18)    Processed-sludge outflow path (19)