Process and apparatus for treating wastewater in a dynamic, bio sequenced manner

DETAILED DESCRIPTION In accordance with -the invention, the above objects are achieved with a process for treating wastewater in a dynamic bio-sequenced manner in a single SBR reactor already filled with an activated sludge-mixed liquor up to a relatively constant level and provided with: a) decantation means which are fixedly mounted inside the SBR reactor at a given height hereinafter called "clear water level", and in and through which supernatant water on top of the mixed liquor within the SBR reactor may freely enter and be discharged out of the reactor when the level of this liquor within the reactor reaches the decantation means; and b) scum and excess sludge removal means which are fixedly mounted within the reactor at a short elevation under the clear water level and in and through which floating scum and excess sludge in suspension may be collected at the end of every decantation step and discharged out of the SBR reactor.
The process according to the invention comprises the steps of: a) rapidly introducing a given amount of wastewater to be treated into the SBR reactor below the clear water level, such a rapid introduction causing the level of the mixed liquor within the tank to raise relatively uniformly and vertically and the supernatant clarified water to enter the decantation means and be discharged out of the reactor; b) actuating the scum and excess sludge removal means to collect and discharge the scum floating on top of the wastewater filling the SBR reactor, such an actuation also causing the level of the wastewater within the SBR reactor to move down below the clear water level of the decantation means; c) mixing and aerating the mixed liquor within the SBR reactor as long as necessary to achieve the required treatment; d) optionally stirring the mixed liquor in a controlled manner within the SBR reactor to bring the sludge totally in suspension within the liquor, and then adding a supplemental amount of wastewater into the SBR reactor to cause a corresponding amount of mixed liquor containing excess sludge to overflow into the scum and excess sludge removal means and thus be removed from the SBR reactor for optional treatment into a digester or a sludge holding tank; e) allowing the sludge in suspension in the liquor to settle for a period of time sufficient to avoid solids to be carried out with the supernatant water when another given amount of wastewater is introduced into the reactor; and f) repeating as long as required steps a) to e) in this order