Control of sludge settling characteristics in the single-sludge system, a hypothesis Academic Article uri icon


  • Abstract Operation of activated-sludge in the single-sludge mode is suggested as an operational device for the prevention of filamentous bulking. It is hypothesized that most filamentous microbes do not possess denitrifying ability and that the denitrifying microbes possess good settling characteristics. It is therefore concluded that nitrogen transformations within the single-sludge system play an important role in the selection of microbial population by affecting the fractionation of organic carbon removal between the aerobic and the anoxic zones. In order to improve sludge settling characteristics, the aerobic volume fraction and the recycle rate should be carefully selected, based on the influent COD/ammonia ratio.

publication date

  • January 1, 1990