| 摘要 |
PURPOSE:To lower the water content of a dehydrated cake, by a method wherein water soluble silicate and a metal ion sequestering agent are added to org. sludge while a cationic high-molecular floccurant is thereafter added to said sludge to form flocs which are then dehydrated. CONSTITUTION:Water soluble silicate and a metal ion sequestering agent are added to org. sludge such as anaerobic digestion sludge of excretion or excessive sludge in activated sludge treatment of sewage or the other various sewages. The water soluble silicate is sodium silicate or potassium silicate and the metal sequestering agent is a monomer or a polymer having a phosphate group or a phosphonate group and sequestering a metal ion. Subsequently, an org. cationic high-molecular flocculant is added to the sludge and the formed flocs are subjected to dehydration treatment such as centrifugal dehydration or vacuum dehydration directly or after separated water is removed from the flocs. The obtained dehydrated cake is subjected to drying, incinerating or composting treatments.
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