The Compare Of Optimizing The Aeration In Submerged Membrane Bioreactor

Membrane fouling and energy consumption are the common obstacles to the wide application of MBR.Fixed aeration intensity usually is used to get steady permeation flux in the project.Large aeration intensity increase circular velocity of membrane surface,which declines sludge aggradation.However,large aeration intensity increases aeration energy consumption in one hand,improves the shearing strength to sludge floc in the other hand,which leads to particle size being smaller and soluble microbial forming.In long running,sludge viscidity will be increased and sludge filtration characteristics will be decreased,which leads to increasing velocity of membrane fouling.This study focused on optimizing the aeration mode of MBR,comparing general MBR with large aeration intensity one.Intermittent aeration mode was expected to advance scouring effect of cross-flow and declined energy consumption.Finally, predominance of the intermittent aeration mode was proved.This paper not only provided design basis,but also accelerated exploiture and practicality of research in MBR.Experiment results showed that the two MBR had no obvious differences in the common targets.Average removal efficiency of COD_cr and NH₃-N was above 80%,60% respectively . Intermittent aeration mode could go along nitration and denitrificationa in a certain extent,so that nitrogen can be degraded completely.At the same time,average degradability of phosphorus was increased partially in the condition of without letting sludge.Sludge filtration characteristics of intermittent aeration MBR was better than another one.SMP had been accumulated badly in the MBR B than MBR A.The two reactors had no clear differences in biologic category;VSS/SS averagely maintained 0.7,which showed that both of them had good activity.Large aeration intensity destroyed framework of sludge floc and increased sludge viscidity;resistance composing of membrane fouling had been changed,settleable fraction resistance (Rc) rate was 85.45%,78.88% respectively,gelation resistance in MBR B was increased to 13.17%.In general membrane bioreactor,effective energy consumption of produced water was about 0.63 kW·h/m³.However,in intermittent aeration bioreactor,the data was 0.4 kW·h/m³,which occupied 63% of the former.Electricity consumption was reduced greatly.