| 摘要 |
<p>PURPOSE:To improve the speed of biodecomposing dithionic acid or the like, by adding organic substance to waste water containing at least dithionic acid or dithionate, and performing anaerobic biotreatment while formed hydrogen sulfide. CONSTITUTION:An outflow liquid mixture 2 from a decomposition tank 4 is degasified by circulating it through a decompression chamber 5 decompressed by a decompression pump 10 and then introduced into a precipitation-separating tank 6. Said liquid is separated into the fraction 12 of precipitating (living) sludge and the fraction 3 of a supernatant liquid in the precipitation-separating tank 6. The fraction 3 of a supernatant liquid is introduced as water for the treatment of decomposing dithionic acid into the process of aerobic treatment to remove BOD components. A part of the fraction 12 of precipitating sludge is returned to a decomposition tank 4 by a pump 11, while the remainder is disposed as excess sludge 13. The removal of gaseous hydrogen sulfide from an inner liquid inside the decomposition tank 4 can be performed by a method such as adding a metal salt, e.g. a ferric one, to the inner liquid to remove it as an insoluble sulfide.</p> |
