浸没式膜-生物反应器中污泥浓度对错流速度及传氧速率的影响

研究了浸没式膜-生物反应器中污泥浓度与膜面错流速度以及传氧速率之间的关系。结果表明,污泥浓度的提高使传氧速率系数下降,当污泥浓度从4.5g/L变化至21.5g/L,传氧速率系数从0.565降低至0.155。根据气液反应器理论进行传质分析表明,传氧速率系数的降低主要是由于污泥浓度增大引起了混合液粘度增大所致。同时污泥浓度的上升会导致膜面错流速度的降低,不利于控制膜污染。

Influence of Sludge Concentration on Cross Flow Velocity and Oxygen Transfer Coefficient in A Submerged MBR

The correlations between sludge concentration and cross flow velocity(CFV) and oxygen transfer coefficient in a submerged membrane bioreactor(MBR) were studied in this paper.The results indicated that oxygen transfer coefficient decreased as sludge concentration increased in the MBR,and it reduced from 0.565 under sludge concentration of 4.5 g/L to 0.155 under sludge concentration of 21.5 g/L.According to the gas-liquid reactor theory,the decrease in oxygen transfer coefficient was mainly coused by the increase in viscosity of the mixed liquors with the increase in sludge concentration.It was also observed that the increase in sludge concentration resulted in the reduction of CFV along membrane surfaces which would influence the operation of the submerged MBR.