Patent ID: 9522832
Filing Date: 2016-12-20
CPC Classification: C02F,Y02W,Y10T

Claim Text:
1. A wastewater treatment apparatus comprising: a reaction tank that includes an upstream-side zone provided on an upstream side of the reaction tank and a downstream-side zone provided on a downstream side of the reaction tank; an air diffusing unit that is provided in the reaction tank and supplies gas to nitrogen-containing water throughout substantially a whole area in a flow direction of the nitrogen-containing water in the reaction tank, so that ammonia contained in the nitrogen-containing water is nitrified to nitrate according to a flow of the nitrogen-containing water through the reaction tank, and the nitrate is denitrified at each position along the flow direction; a denitrification confirming unit provided at a halfway position of the reaction tank along the flow direction of the nitrogen-containing water between the upstream-side zone where a nitrification treatment and a denitrification treatment are processed and the downstream-side zone where the nitrification treatment and the denitrification treatment are processed, which follows the upstream-side zone on a downstream side thereof, to confirm whether the nitrate generated at the halfway position has been denitrified; and a gas supply-amount control unit that controls a gas supply amount from the air diffusing unit at least on an upstream side of the denitrification confirming unit along the flow direction of the nitrogen-containing water, so that a desired proportion of the nitrate is denitrified at the halfway position, based on the denitrification state confirmed by the denitrification confirming unit, wherein a reaction rate of the nitrification treatment and the denitrification treatment in the downstream-side zone is different from the reaction rate of the nitrification treatment and the denitrification treatment in the upstream-side zone, and the halfway position of the reaction tank corresponds to a reaction rate change between the reaction rate in the downstream-side zone and the reaction rate in the upstream-side zone.