Research On Municipal Wastewater Treatment Process Based On Anaerobic Membrane Bioreactor(AnMBR)

As an important contaminant,the municipal domestic wastewater has the characteristics of large amount,complex pollutants and strong environmental damage.In view of these characteristics,traditional wastewater treatment system mainly adopts aerobic activated sludge process and biofilm process,but has problems such as large space,serious energy consumption,high management cost,large sludge production,secondary pollution and so on.Therefore,it is imperative to explore the stability and value of the new wastewater treatment process.This thesis focuses on the application of a new integrated three-chamber forced circulation anaerobic membrane bioreactor(AnMBR)in domestic wastewater treatment,particularly studying on the acclimatization of anaerobic sludge,the rapid start-up of the bioreactor,and also the effects of operating parameters(HRT,circulation and temperature)on bioreactor performance,anaerobic sludge properties and activity,and membrane fouling,in order to ensure the adaptability of the bioreactor in the south area with warm climate.During the experiment,the anaerobic sludge was acclimatized for 111 days,and the anaerobic membrane bioreactor was operated for 175 days.The following results were obtained:The anaerobic sludge with high treatment effect,strong activity,flocculation and sedimentation can be obtained by anaerobic sludge acclimatization,and the anaerobic sludge can be inoculated in the start-up period of the anaerobic membrane bioreactor.The bioreactor starts up quickly on the 21 st day.The treatment efficiency of wastewater in anaerobic membrane bioreactor under different operating parameters(HRT,circulation,temperature)shows that at HRT=12h,the removal rate of COD in the reactor can reach 81.4%,with a balance of energy saving and high efficiency.The maximum removal efficiency of the main pollutants in the reactor with circulation is reduced up to 79.2%;in the simulated temperature comparison experiments in winter/spring(ambient temperature)and summer/autumn(30?),the bioreactor has high efficiency,with COD removal rates up to 75% and 88.4%,respectively.At the same time,anaerobic granular sludge was found,and the properties and activities of anaerobic sludge are improved during the operation of the bioreactor.The membrane fouling,preventing and controlling of the anaerobic membrane bioreactor were further studied.The results show that there is a significant positive correlation between the contamination of anaerobic membrane bioreactor membranemodules and microbial metabolites(EPS and SMP)during the rapid start-up.By observing the microscopic morphology of the membrane surface and inner layer,it was found that the surface of the membrane is mainly fouled of a gel layer,and some areas with sludge layers,and membrane fouling also occurs in the inner layer.Comparing and observing the microscopic morphology of the test film,it was found that the baffle in the reactor and the backwash of biogas have obvious effects on the prevention and control of membrane fouling.This study shows that the new AnMBR has the advantages of short start-up period,high efficiency,energy saving and emission reduction,cost reduction and membrane fouling prevention for municipal domestic wastewater,which is worth to adapt with high research value.