A Dynamics Research Of Treating Rare Earth Ammonia Wastewater By A Submerged Membrane Bioreactor

The membrane bioreactor (MBR), a combined process of biological treatment with advancedmembrane separation, is an innovative and high-efficient technology for wastewater treatment. Inthis subject, submerged membrane bioreactor (SMBR) was established to deal with rare earthammonia nitrogen wastewater. Under the premise of ensuring the effluent’s quality and waterproduction, the experiment focused on researching the running effect of SMBR, inspecting the bestrunning operation and optimal operation parameters, and searching for the optimum runningconditions for mitigating the membrane fouling. Then based on these conditions to establish kineticmodels of microorganism multiplication and excess sludge production model. The purpose of thisthesis is providing a theoretical basis for engineering design and application of SMBR and has asignificance means for SMBR in its treatment of rare earth ammonia nitrogen wastewater.The paper studies results indicated that the removal of CODCrand NH3-N mainly depended onthe biodegradation, the membrane mainly played a role in stabilized effluent quality. Theexperiment studied the effect by running parameters on the process of SMBR treated rare earthammonia nitrogen wastewater, the results showed that the best operation conditions for SMBR are:DO=1.0mg/L, HRT=8h, C/N=3.5, pH between neutral and partial alkalinity. In these conditions, theremoval rate of CODCrand NH3-N was89.3%and80.7%respectively. The orthogonal experimentshowed that the influence on ammonia nitrogen removal rate by these factors in sequence from thebiggest to smallest was DO、HRT、pH value and C/N ratio.Membrane fouling has to be solved during the running process, therefore, the paper studied theoperation way for mitigating membrane fouling. The orthogonal experiment showed the bestoperation conditions were:8minutes of suction time,4minutes of suction suspended time andoxygen capacity is0.05m3/h. The sequence from biggest to smallest which about the influencedegree was suction time, oxygen capacity, suction suspended time.For analyzing operation conditions about Rare earth ammonia wastewater submergedmembrane bioreactor reactor, combined with organic substrates and microbial material balancecalculation. Kinetic models of microorganism multiplication and excess sludge production modelwere established based on Lawrence-McCarty model. The coefficient of sludge theoreticalconversion yield Y and microorganism contabescenceK dwere calculated by linear regressionmethod. The value of Y andK dwere0.587mgVSS/mgCOD and0.1119d1. Visual Basicestablished visual windows for models which were aim to apply the kinetic models convenientlyand had better effect on practical engineering. The maximum sludge concentration was calculatedconveniently with the visual windows.