DEHYDRATION TREATING MATERIAL FOR SLUDGE AND DEHYDRATION TREATMENT

PROBLEM TO BE SOLVED: To effectively utilize sludge and burned ash by using the burned ash having a specific pH in a slurry having specific average particle size and forming a dehydration treating material for sludge. SOLUTION: This dehydration treating material is produced from the burned ash having a pH value of >=7.5 in a 20wt.% slurry having >=10μm average particle size, and the burned ashes of organic waste such as sewerage sludge, pond and lake sludge, food waste, and paper making sludge, etc., or their fused and solidified sludge is used as the burned ash. In filtering and dehydrating the sludge, the burned ash having a pH value of >=7.5 in a 20wt.% slurry having >=10μm average particle size is preliminarily added to a sludge slurry, mixed and treated to form a cake-like shape upon dehydration, and at this time 3.0-70wt.% the burned ash for sludge slurry is preferably added. Also in addition to the burned ash, at least one kind selected from aluminum sulfate, iron sulfate, sodium aluminate, slaked lime and high polymer flocculant may be added.