中空纤维MBR工艺膜堵塞行为与膜渗透性评估

Assessment of Membrane Clogging Behavior and Permeability in a Hollow Fiber MBR Process

采用中试规模的中空纤维膜生物反应器(HF-MBR)处理市政污水,考察了在不同MLSS浓度、不同通量水平下的膜堵塞行为特性及其对膜渗透性的影响。结果表明,随着膜通道堵塞固体质量的增加,膜堵塞面积、堵塞固体积累速率与污泥固体负荷率比率也随之增加,膜渗透性衰减速率加快;膜组件的可持续通量受膜堵塞状态的影响,膜组件经过堵塞之后再次运行时临界通量较未发生堵塞之前会降低;在低MLSS浓度(约为8 g/L)下运行时,化学强化反洗(CEB)能够使系统渗透性得到持续恢复,然而在中、高MLSS浓度(16~32 g/L)下运行时,CEB只能使膜渗透性得到瞬时恢复,离线清堵(Declogging)联合CEB能够保证系统渗透性的持续恢复;此外需要强调的是,经过清洗后膜渗透性得到持续恢复的前提是在可持续通量下运行。

A pilot-scale hollow fiber membrane bioreactor （HF-MBR） process was employed to treat municipal sewage, and the membrane clogging characteristic and its influence on membrane permeability under different MISS concentrations and flux conditions were investigated. The results showed that membrane occluded area, the ratio of clogged solids accumulating rate to sludge solids loading rate and membrane permeability decline rate increased with the increase of accumulated solids in membrane channels; sustainable flux was affected by the membrane clogging condition and its value would decline during the post-clogging operation comparing with that during the pre-clogging operation; CEB could recover the sustainable membrane permeability under low MISS concentration of about 8 g/L, nevertheless CEB could only recover the instantaneous membrane permeability at medium and high MISS concentrations （ 16 to 32 g/L） and declogging and CEB could ensure the recovery of the sustainable membrane permeability; however, it should be noted that the sustainable membrane permeability could be recovered only under the premise of the sustainable flux operation after membrane cleaning.