NOVEL FLOCCULANT AND SLUDGE TREATMENT USING THE SAME

PROBLEM TO BE SOLVED: To obtain a novel flocculant safe to animals and plants and not bringing about environmental pollution without using an acrylamide polymer generating an aluminum salt or a carcinogenic substance being a cause substance of Alzheimer's desease as a flocculant in the sludge treatment of urban sewage/ factory waste water, and a sludge treatment method using the same. SOLUTION: Safety and environment purifying properties are ensured by selecting a substance produced by an organism as a flucculant added at a time of sludge treatment. That is, a flocculant to be used is constituted of a microbiologically produced flocculant and chitin/chitosan obtained from a shell of a crab or a lobster. Especially, a flocculation active substance based on glycoprotein produced by Gram-positive bacteria containing Rhodococcus erythropolis or a flocculation active substance based on acidic polysaccharide produced by a strain of the genus Aureobasidium is used as the microbiologically produced flocculant. Further, as the chitin/chitosan, a chitin/ chitosan obtained by deacetylating 80% or more of chitin is used.