A dissolved air flotation system, comprising: a coagulator operable to mix raw water and a coagulant to form and grow floe; a separator operable to introduce micro air bubbles through nozzles to attach to the floc, to float the floc on water, and to remove floating floc, wherein the separator includes a plurality of flotation basins arranged sequentially in a flowing direction of the raw water, and wherein the plurality of flotation basins are separated from each other by partition walls so that the raw water moves to a neighboring flotation basin along passages formed below the partition walls; a circulating water supply line operable to supply circulating water in which air is dissolved to an interior of the separator, wherein the circulating water supply line includes a plurality of pumps and stabilizers operable to pressurize the circulating water supplied to the separator and ambient air introduced in front of the pump to generate micro air bubbles, the stabilizers being separately mounted behind the pumps so as to retain the air bubbles not completely dissolved therein for a given period of time and thus to dissolve the air bubbles in the circulating water again, and wherein the separator includes: a first flotation basin operable to coagulate and float the floc; and a second flotation basin operable to secondarily float and remove the floc contained in treated water passing through the first flotation basin; and wherein the plurality of pumps and stabilizers of the circulating water supply line are operable to introduce the raw water or the raw water mixed with the coagulant as the circulating water into a lower portion of the first flotation basin and to introduce a treated water as the circulating water into a lower portion of the second flotation basin, wherein the treated water is obtained through the dissolved air flotation system. a coagulator operable to mix raw water and a coagulant to form and grow floe; a separator operable to introduce micro air bubbles through nozzles to attach to the floc, to float the floc on water, and to remove floating floc, wherein the separator includes a plurality of flotation basins arranged sequentially in a flowing direction of the raw water, and wherein the plurality of flotation basins are separated from each other by partition walls so that the raw water moves to a neighboring flotation basin along passages formed below the partition walls; a circulating water supply line operable to supply circulating water in which air is dissolved to an interior of the separator, wherein the circulating water supply line includes a plurality of pumps and stabilizers operable to pressurize the circulating water supplied to the separator and ambient air introduced in front of the pump to generate micro air bubbles, the stabilizers being separately mounted behind the pumps so as to retain the air bubbles not completely dissolved therein for a given period of time and thus to dissolve the air bubbles in the circulating water again, and wherein the separator includes: a first flotation basin operable to coagulate and float the floc; and a second flotation basin operable to secondarily float and remove the floc contained in treated water passing through the first flotation basin; and wherein the plurality of pumps and stabilizers of the circulating water supply line are operable to introduce the raw water or the raw water mixed with the coagulant as the circulating water into a lower portion of the first flotation basin and to introduce a treated water as the circulating water into a lower portion of the second flotation basin, wherein the treated water is obtained through the dissolved air flotation system. a first flotation basin operable to coagulate and float the floc; and a second flotation basin operable to secondarily float and remove the floc contained in treated water passing through the first flotation basin; and wherein the plurality of pumps and stabilizers of the circulating water supply line are operable to introduce the raw water or the raw water mixed with the coagulant as the circulating water into a lower portion of the first flotation basin and to introduce a treated water as the circulating water into a lower portion of the second flotation basin, wherein the treated water is obtained through the dissolved air flotation system.