ACTIVATED SLUDGE METHOD FOR BIOLOGICAL SIMULTANEOUS REMOVAL OF NITROGEN AND PHOSPHOROUS

摘要

The present invention provides an activated sludge method for biological simultaneous removal of nitrogen and phosphorous. The present invention provides a method for removing phosphorus compounds and nitrogen compounds in wastewater, the method comprising: (A) a step for supplying wastewater to an activated-sludge-containing treatment tank to form a mixture of the wastewater and the activated sludge, the step being characterized in that an additional volatile fatty acid or salt thereof is added such that the total amount of volatile fatty acids in the mixture is equal to or greater than the threshold value; (B) a step for non-aerobically treating the mixture in the treatment tank; (C) a step for aerobically treating the non-aerobically treated mixture in the treatment tank; (D) a step for precipitating the activated sludge in the mixture to separate the mixture into the activated sludge and treated water; and (E) a step for withdrawing at least a portion of the treated water from the treatment tank, wherein the activated sludge contains at least nitrifying bacteria, denitrifying bacteria, and phosphorus accumulating bacteria.