Research on orthogonal coagulated setting and coagulation-flotation test of tannery wastewater

The treatment of the tannery wastewater was studied by orthogonal test of beaker coagulation. FeSO4 and alkaline sodium aluminum waste liquid contained NaOH-NaAlO2 were used as flocculants, with polyacrylamide (PAM) as coagulation. When the dosage of FeSO4 was 2.66 g/L (pH 5.5), the wastewater pH value of adding alkaline sodium aluminum waste liquid was 8, and the dosage of PAM was 1 mg/L, the optimum result was obtained. A test device of co-coagulation flotation reactor was designed on the basis of the conglutination of bubble, flocci and turbulent flotation theory. In the device, the gas-1iuid mixed pump substituted the air compressor and the pressure releaser. The combination of coagulation and air flotation were realized. The pump is a new kind of air saturation equipment. The air compressor and the pressure releaser were used commonly in traditional air flotation device. The results of treatment of the tannery wastewater showed a stable state, when the operating pressure was 5×105 Pa, circumfluence ratio was 225%.