Abstract
Cold Circulation Freeze-Drying Equipment of a pilot plant was produced to freeze-dry sewage sludge with a view to recovering cellulose of a biomass resource. The recovery yields of solids and water by the produced equipment were 90.0-96.0% (w/w) and 170-250% (v/v), respectively. The moisture content of the dewatered sewage sludge was about 12%. The cost of the freeze-drying treatment for sewage sludge was estimated to be approximate for present sewage sludge treatment using liquefied natural gas (LNG) waste cold heat. These results also suggested that freeze-drying treatment for sewage sludge did not occur by-products (dioxin, etc.) derived from incineration.
