Study On The Microetch Copper Waste Water Treatment By Magnetic Seeding Flocculation

With the fast development of modern industrialization, heavy metal of industrial drainage has been continually contaminating the environment. Flocculation plays an important role in heavy metal wastewater treatment and directly affects costs of the following process. Hence, how to improve flocculation efficiency, enhance solid-liquid separation effect and save floor space has been a valuable study direction in wastewater treatment.Magnetic seeding flocculation becomes a hotspot in industrial wastewater treatment in recent years. It is based on traditional flocculation, with magnetic seed as its core of flocculation reaction, forming microbial floes, accelerating the collision and adherence to further become high density of magnetic floc. In comparison with traditional flocculation, it accelerates the floc settling speed, shortens the settlement time and greatly enhances the flocculation efficiency. So it is recognized as one highly efficient solid-liquid separation treatment process.This study mainly focuses on magnetic seeding flocculation in simulation microetch copper waste water. It consists of three parts. The first part compared the similarities and differences in heavy metal wastewater treatment of flocculation experiment dosing with magnetic seed and micro sand. The second part was determining the optimal conditions of magnetic seeding flocculation by doing orthogonal experiments. The third part was based on the second part, and how the dosage or particle size of magnetic seed affectd the settling speed, floc size, floc volume and moisture percentage. This study concentrates on magnetic seed effectiveness regularity and mechanism, giving theoretical and practical support to this method in heavy metal wastewater treatment.The results suggest that:(1) the best experimental conditions of magnetic seeding flocculation are PAC 1.8 g/L, PAM 0.015 g/L, pH 9.5, and magnetic seed 2.0 g/L, size between 300 and 400 mesh, settling time 8 minutes, in which Cu2+ and turbidity removal rates are 98.53% and 94.72%, respectively.(2) the best experimental conditions of micro sand flocculation are PAC 1.8 g/L, PAM 0.015 g/L, pH 9.5, and micro sand 2.0 g/L, settling time 8 minutes, in which Cu2+ and turbidity removal rates are 97.45% and 93.24%, respectively.(3) orthogonal experiment determines the priority order of influence factors in removing Cu2+, it is pH>magnetic seed dosage>magnetic seed size>PAM dosage>PAC dosage. The dosing of magnetic seed improves the heavy metal removal rates in industrial wastewater treatment, compared with only increases the dosage of PAC or PAM.(4) settling speed of magnetic seeding flocculation is significantly faster than traditional flocculation,and it reaches maximum of 5 cm/min, 2.64 times greater than traditional flocculation(5) when dosage and size of magnetic seed are 2.0 g/L and 300~400 mesh, respectively, floc size D50 reaches its maximum of 41.94 ?m, 20 micrometers larger than traditional particle size. The floc growth rate is affected by magnetic seed dosage and particle size.(6)Dosing magnetic seed makes the floc more condensed, and the volume of sludge reduces significantly, lightens the following sludge treatment process and enhances the treatment efficiency.(7) The dosing of magnetic seed squeezes the free water in the intervals out and reduces the moisture percentage of flocs.