| 摘要 |
<p>PURPOSE:To contrive the complete decomposing separation of dithionic acid, by applying the method of adding an S compound such as thiosulfate in the treatment of waste water with activated sludge to a supernatant liquid from a precipitation tank after treating the titled waste water with activated sludge. CONSTITUTION:Waste raw water from which SS, metal components, etc. have been removed is sent through a line 1 into a nitrification tank 3 and treated therein by mixing it with returned sludge through a line 5. Waste water flowing out of the tank 3 is denitrified in a denitrification tank 17 and then aerated in a reaeration tank 25. After the treatment with activated sludge is finished, the waste water is subjected to precipitating treatment in a precipitation tank 33. The resulting treated water is supplied for secondary treatment with activated sludge, by introducing it into the aeration part 43 of a disposal tank 41, injecting air through a sparger pipe 47 and adding alkali substance through a line 49 to hold the pH of the liquid at 6-8. In addition, to accelerate the decomposition of dithionic acid in the aeration part 43, at least one of S and S compounds in an amount of 1-2mol based on 1mol of dithionic acid is added.</p> |
