PURPOSE: To prevent generation of methyl mercaptan and methyl sulfide by using a powder sterilizer as a deodorizer, thereby transferring the deodorizer to a cake side after dehydration and anaerobically decomposing org. matter.
CONSTITUTION: The powder of 1,2-benzoisothiazolone (one kind of the deodorizer) is suspended in water and is added in this state from a line 2 to a mixture composed of the first settling basin sludge of sewage, the excess sludge of activated sludge and the withdrawn sludge in an anaerobic digestion treatment of the excess sludge; thereafter, a high-polymer flocculating agent is added from a line 3 to the mixture to form flocs which are then supplied to a belt press type dehydrator 4 and are thereby dehydrated. As a result, the 1,2- benzoisothiazolone migrates to the cake side after the dehydration, thus exhibiting strong restraining power to septic bacteria and sulfate reducing bacteria. The org. matter is thereby anaerobically decomposed and the generation of the methyl mercaptan and methyl sulfide is prevented; in addition, the sulfate is reduced to prevent generation of hydrogen sulfide.
MARUOKA REIJI
HINA SEIYA
MAGATA HIROYUKI
KURITA WATER IND LTD
| JPS6257698A | 1987-03-13 | |||
| JPS6178499A | 1986-04-22 | |||
| JPS59112811A | 1984-06-29 |
Next Patent: ANAEROBIC DIGESTION METHOD WITH FLUIDIZED BED