Analysis On Efficiency Of Magnetic Technology Intensified MBR Process For Vessel Oily Wastewater Treatment And Membrane Fouling Control

Vessel oily water has always been an important source of marine pollution,which are easily diffusivity,refractory,and toxic.The feature of Vessel oily water has brought certain difficulty to marine oily sewage treatment.In addition to the standard of the international maritime organization?IMO?,more and more stringent oily wastewater discharge standards were enacted by the coastal countries and domestic,the traditional oil-water separators meets the requirement of the standard gradually difficult,so oily sewage must process deeply to meet the requirements of discharge.The process of combined MBR has some advantages,such as simple and compact structure,reliable operation,energy saving,good effluent,resisted membrane fouling.This kind of process is regarded by the researchers at domestic and abroad and being applied to practice.Dosing magnetic powder affecting the effectiveness of vessel oily wastewater treatment of MBR reactor and the membrane fouling were investigated.The mechanism of magnetic powder improving the characteristics of sludge then retarding membrane fouling was investigated.In the paper,the PM-MBR?Powder Magnet-MBR?is added with Fe₃O₄ powder,the MBR is ordinary MBR.?1?The powder dosage of PM-MBR is 650mg/L which was determined by pilot test.During the trial operation,COD_cr and oil content were always under 30mg/L and0.25mg/L in effluent of PM-MBR.?2?During the operation period,organics and oil removal efficiency of two reactors also fulfill the effluent requirements of national standard.There was so little difference of oil in effluent between two reactors,but the COD_cr removal efficiency of PM-MBR slightly higher.In the short HRT,COD_cr removal efficiency declines in the two reactor,while because the effect of magnetic powder,the PM-MBR has more effective ability of removal sewage.?3?In research,we found that improving aeration intensity for membrane and suction suspended time can retard membrane fouling.Membrane fouling rate in PM-MBR was always lower than MBR under operation conditions,this shows that magnetic powder can help retarding membrane fouling.?4?Observe membrane surface through?scanned electron microscopy?SEM,the PM-MBR membrane surface had accumulated to less bacteria and affiliated products.Besides,the FTIR spectrum shows the main pollutants on membrane surface are polysaccharide and protein.There are a lot of correlations between membrane fouling rate and EPS,SMP.Magnetic powder can speed up the biological metabolism to reduce the concentration of EPS and SMP,in turn,it can slow down membrane fouling rate.?5?Magnetic powder has changed the growth environment of microorganisms,promoted growth and reproduction of microorganism,improved the ability of the sludge resists aeration shear and.settling performance.The average diameter of granules has increased 40.5%,the mixture viscosity has decreased 3.5%,and Zeta Potential has increased 12.5%.Under the effect of aeration shear force,magnetic powder slows down the sludge cake layer formation and the increase of the transmembrane differential pressure,thus slow down the membrane fouling.