Experimental Research On Simultaneous Nitrification And Denitrification In Complex MBR

Membrane bioreactor(MBR) is a reasonable combination of biological treatment technology and membrane technology, Complex membrane bioreactor is a reactivity system of adding filler in the bioreactor, which can keep the activated sludge and biofilm concomitance. It could reduce the amount of MLSS, and alleviate the membrane pollution when adding the filler in the bioreactor, at the same time, the ability of resisting impact load of the system will be stronger, and there will be a large scale anaerobic area in the biofilm, that is advantaged of denitrification. The removal efficiency of TN is above 90% in the system.The impact of COD and TN removal efficiency by DO, C/N, HRT and pH is the main research aim in the paper. If DO too low, microorganism grow and removal of pollutions can not be satisfaction. If DO too high, that will expand the aerobic area of the system, aerobic microbial will increase rapidly, increasing the consumption of COD, so the removal efficiency of TN decline. The best range of DO is l~2mg/L.C/N is the key index of removal efficiency in complex membrane bioreactor, The system keep high removal efficiency when declining the influx concentration of NH3-N and keeping the COD changeless. But the removal efficiency will decline when declining the influx concentration of COD and keeping the NH3-N changeless. The Effect of removal efficiency will better than before when running enough long time. It shows that the system have the Self-regulation.pH value is also the key index of microbial growing and the speed of nitrification and denitrification. pH value too high or too low can restrain the growth of microbial, the vital activity and metabolism of microbial is strongly related to pH. The removal efficiency of membrane bioreactor have biggish fluctuate, when pH value change in the scope of 5-9.5. The best pH value scope is 7-8.5.Change the HRT in the scope of 5, 8, 10, 15, experiment show that the best HRT is above 8h of removal COD and NH3-N, and the best HRT is 8-10h of removal TN, so 8h is the best HRT of experiment.HRT is strongly related to MLSS, when HRT lower, the microbial is in the growth phase, gets more nutrition, growth quickly, the MLSS increasing, when HRT higher, the microbial is in the contabescence phase, becoming aging, MLSS decline than before. So every effect factors must keep stable, the system can have the better removal efficiency.Nitrification and denitrification accord with the theory of maldistribution of DO and theory of deficiency of oxygen in microenvironment. DO is the key factor of nitrification and denitrification, the experimental configuration and the MLSS also influence in the nitrification and denitrification, the impact of removal efficiency by all effect factors is throughout change the MLSS and microbial active achieve.