Test Of Selecting Coagulant For The Sanctifier Of Highly Efficient Sewage Treating Dairy Wastewater

The test adopted the sanctifier of highly efficient sewage, which treated Fuyang dairy wastewater. The test selected three types of inorganic flocculants ,which were aluminum sulfate(AS), polyaluminum chloride(PAC)and polyferric sulfa(PFS),and one type of organic flocculants, which was polyacrycamid(PAM). The test researched the effects of inorganic flocculants, analyzed relation of dosage with the removal of COD and turbidity. Finally, got the optimized dosage respectively. The test also studied the effects of AS, PAC, PFS mixed with PAM respectively, analyzed the relation of dosage with the removal of COD and turbidity and then got the each best combinations. In the end, obtained the best and the most economic one. At the same time, the cost of every coagulant were compared. The main conclusions of the test as following three:1 .Inorganic flocculants: the optimized dosage of AS was 390mg/L, the removal of COD and turbidity was about 93% and 68%, the cost of AS was 0.234yuan per cubic meters; the optimized dosage of PAC was 320mg/L, the removal of COD and turbidity was about 94% and 74%, the cost of PAC was 0.512yuan per cubic meters. the effluent chroma was high when PFS was used,so it wasn't fit for the system.2.Inorganic flocculants united with organic flocculants: the best combinations of AS as following three: the first, the dosage of AS was 270mg/L and the dosage of PAM was 0.7mg/L; the second, the dosage of AS was 300mg/L and the dosage of PAM was 0.5mg/L; the third, the dosage of AS was 330mg/L and the dosage of PAM was 0.3mg/L, the removal of COD and turbidity under the best combinations was about 94% and 69%,the cost of coagulants was 0.176yuan per cubic meters,0.19yuan per cubic meters, 0.204yuan per cubic meters in correct order. The best combinations of PAC as following two: one combination was the dosage of PAC was 240mg/L and the dosage of PAM was 0.5mg/L, the other combination was the dosage of PAC was 280mg/L and the dosage of PAM was 0.3mg/L, the removal of COD and turbidity under the best combinations was about 94% and 74%, the cost of coagulants was 0.394yuan per cubic meters. 0.454yuan per cubic meters in correct order. So the best and the most economic combination was the dosage of PAC was240mg/L and the dosage of PAM was 0.5mg/L.3. Through the orthogonal experiment, we knew that the main factor of affecting the effects of the system was the dosage of inorganic flocculants, types of inorganic flocculants was the second, different amount and the dosage of organic flocculants affected the effects slightly.