Patent ID: 7674380

Claim:
An apparatus for treating sewage using semi-batch, comprising: an aeration tank, in which an aeration unit aerating sewage continuously to be in an aerobic condition is installed; a thickening tank, of which the top is open, including side walls having a height lower than that of the aeration tank and arranged in the aeration tank, for continuously settling and thickening sludge of sewage aerated in the aeration tank and overflowing therein in an anoxic condition and, then, discharging the thickened sludge to the outside by a pump; a dephosphorization tank, including an anti-swirl plate established on the bottom thereof, of which the width narrows toward the top, for receiving upwardly raw water and the thickened sludge discharged from the thickening tank, stirring the same in an anaerobic condition, and continuously overflowing dephosphorized sewage through a weir established on the top circumference thereof; a first reactor basin and a second reactor basin, each including an opening portion, formed by opening a side wall thereof to be connected with a lateral portion of the aeration tank, and an aeration unit installed therein, the first reactor basin and the second reactor basin being arranged in parallel in the longitudinal direction; a flow distribution pipe including a start pipe, connected with a lateral portion of the weir of the dephosphorization tank and extending toward the bottom, and a pair of flow pipes, each extending from an end of the start pipe and curved to be parallel to the bottoms of the first reactor basin and the second reactor basin in the longitudinal direction and including an auxiliary pipe at one side thereof; a pair of stirrers, each being established at one side of the auxiliary pipes in each of the pair of flow pipes, operating in turn to stir the dephosphorized sewage overflowing from the dephosphorization tank to the first reactor basin and the second reactor basin alternately; and a decanter, installed across the top of the opposite side to the opening portions of the first reactor basin and the second reactor basin, for alternately decanting purified supernatant overflowing in turn from the first reactor basin and the second reactor basin.