PILOT-PLANT TEST OF ELECTRON-BEAM DISINFECTED SLUDGE COMPOSTING

A pilot plant was built to get information on scale-up factors of composting plant of electron-beam disinfected sludge cake. The amount of sludge to be treated was about 500 kg/batch. A Cockcroft-Walton type of electron accelerator and a machine to make thin layer of sludge were used for sludge disinfection. The composting plant consisted of a mixer, a granulating machine, a fermenter with three screw-type mixing blades, and a conveyer system. Efficient composting could be realized also by the pilot plant, by controlling fermentation temperature in the optimum range, by controlling air flow rate and by frequent mixing in the fermenter. From an economic feasibility study based on the results of pilot plant test, capital cost and treatment cost for the process are expected to be lower than those for conventional one, when the treatment capacity of plant exceeds 50 ton/day.