Dissolved air flotation machine design needs to consider what aspects, can make the air flotation machine in the treatment of sewage more efficient, look at the following eight points:

(1) to fully study the water quality of the treated water, analysis of the rationality and applicability of the use of air flotation process;

(2) in the case of a condition, the need for the treatment of waste water should be necessary to carry out a small test or model test. According to the test results, the appropriate solution gas pressure and reflux ratio were selected. Generally, the solution gas pressure is 0.2~0.4MPa, the reflux ratio is 5%~100%, and the reflux ratio is determined by the concentration of the suspended matter. Concentration of high reflux ratio, concentration of small reflux ratio.

(3) according to the test, the type of coagulant, dosage, flocculation time, reaction degree, determine the reaction form and reaction time, the general precipitation reaction time is shorter, with 30 a 2 minutes is appropriate;

(4) determine the pool type of flotation tank, should be based on the structures of water treatment, water purification process and before and after the treatment of cohesion, the surrounding terrain and structures of coordination, difficulty of construction and cost factors to be taken into account. The reaction pool should be flotation tank. In order to avoid breaking the flocculation, we should pay attention to the form of the structure. The flow rate of the inlet chamber should be controlled within S / 0.1M;

(5) the contact room must provide good contact conditions for the air bubble and the flocculation body, and the width should be considered for installation and maintenance requirements. The rising velocity of the water flow is generally 10~20mm / s: the residence time of the water flow in the room should not be less than 60 seconds.

(6) according to the degree of difficulty and the treatment of water quality, the air separation chamber should be based on the difficulty and the water quality. Select the flow (down) of the flow rate, generally take 1.5~3.0mm / s, that is, the surface of the separation chamber load rate of 5.4~10.8m3/ (m2.h);

(7) the effective water depth of the air floatation pool is generally 2.0~2.5m, and the residence time of the water flow in the pool is generally 10~20min;

(8) the length and width of the flotation tank than without strict requirements; in general, single width is less than 10m, the cell length is not less than 15m;