Apparatus for Treatment of Domestic Wastewater Combining Continuous SBR and Contact Aeration Tank and Method Therefor Using the Apparatus

摘要

PURPOSE: Provided are an apparatus and a method for treating wastewater using a sequencing batch reactor (SBR) and a contact aeration tank, which can treat wastewater with high efficiency by synergy effect of the SBR and the contact aeration tank. CONSTITUTION: The apparatus comprises a wastewater tank(2) for storing wastewater; a sequencing batch reactor(3) with a tank having a wastewater inlet at the bottom thereof and a treated water outlet at an upper portion thereof, an impeller(12) connected to an agitator(10), an air diffuser(13) connected to an air supply unit(8), and a sludge drain for discharging excess sludge, wherein the tank is operated under a settling condition for settling pollutants in wastewater by gravity force, under a wastewater influent/effluent condition, under an anoxic condition for reducing nitrate to nitrogen, under an anaerobic condition for releasing phosphorous from denitrifying microorganisms, and under aerobic condition for nitrifying nitrogen, luxury uptake of phosphorous, multiplication of microorganisms in turn; a contact aeration tank(4) with a water inlet and an outlet at an upper portion thereof, an air diffuser(16) and contact media(15) onto which microorganisms are immobilized for biologically treating wastewater; and a return pipe(21) for returning effluent water of the contact aeration tank(4) to the sequencing batch reactor(3). The method comprises the steps of (a) settling wastewater and separating into a first sludge layer and a first decant water in a sequencing batch reactor, (b) introducing wastewater to the first sludge layer from the bottom of the reactor while discharging the first decant water by the same amount of wastewater introduced into the reactor, (c) reducing NOx-N to N2 by denitrifying microorganisms by operating the reactor under an anoxic condition, (d) releasing phosphorous from denitrifying microorganisms under anaerobic condition, (e) nitrifying N using organic material, causing luxury uptake of phosphorous by microorganisms, and discharging the microorganisms under aerobic condition, (f) biologically treating remained pollutants in the outflow of the sequencing batch reactor by bringing the pollutants into contact with air and contact media in a contact aeration tank, (g) returning a portion of the effluent water of the contact aeration tank to the sequencing batch reactor and transferring the other portion of the effluent water to a settling tank, thereby separating it into a second sludge layer and a second decant water.