Abstract: Provided is a wastewater treatment apparatus for removing nitrogen and phosphorus having an anaerobic tank, an anoxic tank, an aerobic tank and a clarifier, wherein the aerobic tank includes has a baffle installed at one side thereof to form a dissolved oxygen reducing zone for reducing the concentration of dissolved oxygen contained in internally recycled wastewater returned from a dissolved oxygen reducing zone while increasing the concentration of dissolved oxygen contained in treated effluent supplied from a part other than the dissolved oxygen reducing zone of the aerobic tank to a clarifier in a subsequent stage. Since organic matter present in wastewater is effectively used, the efficiency of removing nitrogen and phosphorus can be increased and the amounts of oxygen required throughout the treatment process and organic matter required for denitrification can be reduced. Also, synthesis of cells of microorganisms is suppressed. Therefore, the repair and maintenance costs can be reduced.

Abstract: Provided is a wastewater treatment apparatus including a bottom portion and a plate formed above and spaced apart from the bottom portion to form a lower chamber with the bottom portion, an outlet installed on the bottom portion for drawing off water and sludge in the lower chamber before backwashing, a filter medium layer supported to the upper portion of the plate by the plate, the upper layer of which forms a bottom portion of an upper chamber, a wastewater introducing means connected to the lower chamber, for introducing wastewater to be treated into the lower chamber, a process air introducing means for supplying process air to the filter medium layer formed over the plate, a plurality of aerators formed over and spaced apart a predetermined distance from the plate, and mounted in a plurality of air flow pipes led to the process air introducing means, a backwash air introducing means for supplying backwash air to the lower chamber during backwashing, a backwash water introducing means for supplying backw

Abstract: Provided is a wastewater treatment apparatus including a bottom portion and a plate formed above and spaced apart from the bottom portion to form a lower chamber with the bottom portion, an outlet installed on the bottom portion for drawing off water and sludge in the lower chamber before backwashing, a filter medium layer supported to the upper portion of the plate by the plate, the upper layer of which forms a bottom portion of an upper chamber, a wastewater introducing means connected to the lower chamber, for introducing wastewater to be treated into the lower chamber, a process air introducing means for supplying process air to the filter medium layer formed over the plate, a plurality of aerators formed over and spaced apart a predetermined distance from the plate, and mounted in a plurality of air flow pipes led to the process air introducing means, a backwash air introducing means for supplying backwash air to the lower chamber during backwashing, a backwash water introducing means for supplying backw