Study On Advanced Treatment Technology Of Magnetic Field And Ozonation Composite Strengthening Coagulation

The magnetic field has a promoting effect on chemical reaction. In order to improve efficiency of the wastewater treatment, magnetic treatment technique can be used as an effective strengthening measure for conventional technology of wastewater treatment. In this study, magnetic field was combined with advanced wastewater treatment technology. Study on magnetic field stregtheing coagulation, magnetic field stregtheing ozonation, magnetic field and ozonation compsite stregtheing coagulation in the application of advanced wastewater treatment.Main results and conclusions are as follows:(1) The results of the study on magnetic field-intensified coagulation show that the treatment efficiency of magnetic field-intensified coagulation was superior to coagulation. The data obtained show that PAC are the optimal coagulant whose optimal coagulant dose is 8mg/L in static coagulation test. The removal efficiencies of COD_Cr, UV₂₅₄, turbidity, colority by coagulation treatment were 20.77%, 31.13%, 58.78%, 34.93% respectively. In the test of magnetic field-intensified coagulation advanced treatment for municipal wastewater, the suitable operating conditions were: the dosage of PAC was 7 mg/L, the magnetic field intensity was 3000Gs, and magnetizing time was 5 min. The average removal of COD_cr, UV₂₅₄, turbidity and colority in magnetic field-intensified coagulation treatment test were 31.72%, 44.69%, 62.08% and 41.12% respectively. The removal rates increase by 6.19%, 10.95%, 13.56%, and 3.30% respectively compared with the removal rates in coagulation treatment test.(2) The study on magnetic field-intensified ozonation show that the magnetic field plays a certain role in the ozonation advanced treatment for municipal wastewater, it can accelerate reaction velocity of ozonation. In the test of ozonation, the optimal ozone dose was 3.5mg/L, the contact time was 10 min, and the removal efficiencies of COD_cr, UV254, colority were 33.95%, 65.47% and 76.40% respectively. In the test of magnetic field-intensified ozonation treatment for municipal wastewater, the suitable operating conditions were: the dosage of ozone was 3.5 mg/L, the magnetic field intensity was 3000Gs, and the contact reaction time was 10 min. Under the optimal condition, the average removal of COD_Cr, UV₂₅₄ and colority were 34.30%, and 73.33% 87.43%, respectively. Compared with the removal rates of COD_Cr, UV₂₅₄ and colority in ozonation test the removal rates increase by 0.35%, 7.86% and 11.03% respectively (3) The study on ozonation enhanced coagulation showed that the treatment effect of secondary effluent was good, when PAC dose was 4.0 mg/L, ozone dose was 2.0mg/L, average removal rates of COD_cr, UV₂₅₄, turbidity and colority could reach 43.10%, 63.05%, 74.16% and 63.89% respectively. Magnetic field and ozonation compsite stregtheing coagulation applied to advanced treatment for municipal wastewater had a better treatment efficiency,when PAC dose was 4.0 mg/L, ozone dose was 2.0mg/L, the magnetic field intensity was 3000Gs and magnetized during ozonization treatment. Under this condition, the average removal rates of COD_Cr, UV₂₅₄, turbidity and colority increase by 4.59%, 5.10%, 4.89% and 14.82% respectively compared with the removal rates in ozonation enhanced coagulation test.