Aerator for water treatment

The aerator comprises an air inlet pipe, a mixing disc and a submersible electric pump which are sequentially arranged from top to bottom, and the mixing disc is provided with an aeration cavity with an opening in the upper end and a plurality of flow channels communicated with the aeration cavity; a second impeller is arranged in the aeration cavity and is connected with the submersible electric pump; the second impeller is a radial impeller; the top end of the air inlet pipe is positioned above the liquid level, the bottom end of the air inlet pipe is positioned in the aeration cavity, and the air inlet pipe is communicated with the aeration cavity; a plurality of second cutting groove groups are formed in the inner wall of the aeration cavity in the circumferential direction at equal intervals, and each second cutting groove group is located between two adjacent flow channel inlets; and each second cutting groove group comprises 2-4 second cutting grooves which are vertically distributed. According to the