Experimental Study Of An Anoxic/aerobic Membrane Bio-reactor

Membrane bio-reactor technology has many advantages, which are not possessed by traditional methods and it has the very good application prospect, and has been widely used in domestic sewage and industrial waste water treatment. The study combined with anoxic / aerobic process and membrane bio-reactor, investigated the treatment efficiency of pollutants in domestic sewage and brewery wastewater. And the influence of internal recycle ratio and influent loads on the pollutant removal. The system has a better removal effect of COD, ammonia nitrogen and turbidity for domestic sewage. The average removal rates were 86.5%,98.4%,99.14%, and the removal effect werenot affected by internal recycle ratio. As internal recycle ratio increased, the removal rate of TN increased. The removal rate was 80% when the internal recycle ratio was 300%. The system has a better removal effect of COD, ammonia nitrogen and turbidity for brewery wastewater. The average removal rates were 95.74%,97.84%,99.5%. The denitrification efficiency also went well in the system. The removal effect werenot affected by influent load. When the influent COD volumetric loading from 1.5kgCOD/(m~3·d) to 3.75kgCOD/(m3·d), the effluent always maintained below 100mg/L. The sludge load, which always maintained below 0.45kgCOD/(kgMLSS·d) in the operation process, to ensure the removal effect of pollutants. The COD removal rate always maintained above 94% in the operation process. The nitrate sludge loading in the anoxic area, which between 0.13 and 1.55kgNO3--N/(kgMLSS·d), was 1.5～20 times higher than that under conventional process. Although the pH was 5.8～7.1 in aerobic area, the system has better removal effect for pollutants. The removal of pollutants mainly rely on biochemical action and intensified removal by the membrane, the former plays a major role. The jet aeration was used in the membrane bioreactor in our research. Oxygen transferring rate and utilization efficiency was improved highly using jet aeration and dissolved oxygen(DO) was enough. Sludge grain was broke into pieces by jet aeration and shear action of circular pump, improving highly biological efficiency. Though compare the pollutants removal by new membrane and used membrane, the result showed that cake layer play more important role than filtration by membrane for pollutants removal. Therefore, more cheaper membrane can be used in engineering application, and economics can be improved.