SURPLUS ACTIVATED SLUDGE REDUCTION METHOD

摘要

PPROBLEM TO BE SOLVED: To provide a surplus activated sludge reduction method which is excellent in efficiency of heating energy, and promises a remarkable reduction of moisture content. PSOLUTION: In the reduction method, surplus activated sludge discharged by biological treatment is stored in a heat treatment tank, and at the same time steam is directly supplied into the sludge. Heat treatment is carried out at a prescribed temperature for a prescribed time period, and then the heated surplus activated sludge is dehydrated and solidified, and further dried. It is more desirable that the temperature of the surplus activated sludge in the heat treatment tank is maintained at 60-70C, and it is desirable that gas at 20-40C is supplied into a dry atmosphere. Spontaneous drying and/or drying by heating may be adopted for drying of the heated sludge after crushing cakes dehydrated by a compression method. As the compression method, a normal method is used. Conventional technology, such as mechanical compression, centrifugal compression, and spontaneous compression, may be used. PCOPYRIGHT: (C)2007,JPO&INPIT