Effect of Residual Magnetic Properties of Soft/Hard Magnetic Powder on The Efficiency of Its Supported Active Sludge Process in Water Treatment
Traditional activated sludge method is always poorly tolerant of toxic pollutants and the big change of sludge loading,and then leading to a decreased treatment efficiency.Magnetic powder-supported activated sludge technology has been developed to possibly overcome this problem,in which hard magnetic ferrofenric oxide is always used.Demagnetization treatment is needed because of residual magnetic properties in recycle of ferroferric oxide,leading to high cost.Soft magnetic powder has no residual magnetic properties,but its supported-activated sludge has not been studied so far.The study investigated the difference in treatment efficiency of self-prepared wastewater and dyeing wastewater by the pre-magnetized ferroferric oxide-supported activated sludge process and soft ferrosilicon aluminum-supported one,thus promoting the development of latter technology(without demagnetization equipment).The results showed that the removal rates of CODCr and NH3-N were 94.21％and 97.01％,90.03％and 92.10％in ferrosilicon aluminum group and ferroferric oxide group under the same conditions,respectively,both higher than those of the controlled one(86.81％and 76.40％).Similar results were obtained in treatment of dyeing wastewater.the removal rates of CODCr and NH3-N were 94.21％and 97.01％,90.03％and 92.10％in ferrosilicon aluminum group and ferroferric oxide group,respectively,both higher than those of the controlled one(86.27％and 76.04％).The results of sludge-magnetic powder separation efficiency indicated that the recovery rates of powder were 90.94％and 81.39％for ferrosilicon aluminum and ferroferric oxide,respectively.Considering the above results and the cost of demagnetization(including equipment investment and energy consumption),ferrosilicon aluminum-supported activated sludge has better application prospect.
magnetic powder-supported activated sludgebiochemical treatment efficiencysoft magnetic ferrosilicon aluminumhard ferroferric oxidemagnetic powder recovery
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