Effects of aeration on suction pressure in a submerged membrane bioreactor

Abstract A membrane bioreactor (MBR) is one of the application of membrane technology to wastewater treatments. A submerged MBR is a type of MBR in which membrane modules are directly submerged into a bioreactor. Because the uplifting air flow is assigned the role of cake removal in a submerged MBR, aeration could affect the cake-removing efficiency and hence suction pressure. This study, therefore, examined the effect of aeration on cake removal and suction pressure using a pilot-scale submerged MBR and concluded that aeration was a significant factor governing the filtration conditions. Judging from the observed flow velocity of uplifting air measured with an electromagnetic flow velocity meter, cake-removing efficiency of the uplifting air flow was affected by the turbulence of the flow. The cake-removing efficiency was improved either (1) by augmenting an air flow rate or (2) by augmenting aeration intensity (an air flow rate per unit floor area) by concentrationg membrane modules over a smaller floor area.