Effect Of Treating Sanitary Waste By Bioferric-SMBR

This study use the characteristics of membrane bioreactor(MBR)and biological iron in the traditional active sludge to form a new MBR process called bioferric-SMBR.The experiment studies systematically the effect of simulated sewage treatment,the sludge characteristic and the membrane fouling under the condition of different dose of Fe(OH)₃ into the submerged membrane bioreactor.The operating condition of bioferric-SMBR is optimized based on the discussion of dose,sludge concentration,and microorganism characteristic.(1)The bioferric-SMBR process enhances the effluent quality.The optimal dose of Fe(OH)₃ into SMBR is 5%of sludge mixture concentration.The COD,total P,and NH₃-N of the effluent in bioferric-SMBR is higher than the ordinary SMBR 6.15%, 12.36%and 1.39%on the condition of this experiment.(2)Bioferric sludge has better aggragate structure on the Fe(OH)₃ dose of 5%,which decrease the resistance of filter cake layer effectively on the surface of membrane and release blocking in membrane pores.However,bioferric sludge structure seems disaggregate with the dose increasing to 7%,and thus weaken the adsorption of soluble organic substance.In addition,the higher organic matter consumption multiplies the massive filamentous bacterium,and the filamentous bacterium release more extracellular polymeric substances to aggravate membrane pollution.(3)Soluble extracellular polymeric substance(EPSs)are the primary factor causing the membrane pollution by analysis the realationship between EPSs,LB and the variation of semi-permeable membrane pressure in the mixture.Under the dose of Fe(OH)₃ increasing to 7%,polysaccharides in EPS increases and cause more severe membrane pollution.(4)When Fe(OH)₃ dose increase to 5%of sludge concentration,the content of polysaccharide enhances significantly compared to the protein.The main matter is polysaccharide along with reduction of sludge load.