Magnetic Particle On The Biological Treatment Of Heavy Metal Wastewater Impact

The traditional methods for removing heavy metals have several disadvantages when metals are present in concentrations lower than 100 mg/L. Biosorption, which use s biological materials as adsorbents, has been considered as an alternative method.In this work, the effect of magnetic field produced by magnetic powders, such as Fe3O4, fixed permanent magnetic powders were investigated. Moreover, the mechanism of magnetic field and flocculation, and the filtration of bacterium were researched too.Fe3O4 and fixed permanent magnetic powders were chosen as the source of magnetic field and added into the culture medium. The permanent magnetic powders were fixed by rubber and Sodium Alginate-glutin respectively. Strain A and B were provided by the lab, while strain 7# and 2# were filtrated from the printing and dyeing wastewater.The results indicated that the strain A and B propagated well and had high flocculation activity under a certain concentration of Fe3O4. As the Fe3O4 concentration was 4g/L culture medium, the cell numbers of A and B with magnetic field were two times of those without magnetic field in state period. What's more, cell B with magnetic field came into state period 4 hours ahead of the comparison. The maximum copper removal rate of A was 73.53% and was 35.76% higher than the comparison. While the maximum copper removal rate of B was 66.91% and was 23.4% higher than the comparison. The maximum copper removal rate was both present in anaphase of the state period or prophase of the death period.The permanent magnetic powder fixed by rubber has so strong magnetic intensity that restrained the microorganism's growth.As the concentration of the permanent magnetic powder embedded by Sodium Alginate-glutin is 0.065g/L, it can improve microorganism's growth and flocculation activity obviously. The effect of magnetic field on microorganism's growth, no matter accelerating or restraining, is just temporarily change its activity and will gradually go steady as time goes on.It was demonstrated by the distribution of flocculating activity that both the biomass and the extracellular polymers have a good capacity of removing metals. It was showed that pH value of the biomass influences the flocculation apparently. The maximum copper removal rate of 88.76% was obtained as adjusted the pH value of the biomass to 10. What's more, the experimental results showed that the adsorption accorded with Langmuir and Freundlich sorption models.