基于跨膜压差变化的超滤膜污泥污染特性研究

Pollution property of activated sludge on ultrafiltration membrane under different transmembrane pressures

通过构建错流式膜生物反应器(MBR),在恒通量运行模式下,研究了跨膜压差变化条件下活性污泥对超滤膜的污染特性。在跨膜压差分别为20、40、60和80 kPa条件下考察了活性污泥对超滤膜的膜污染速率、膜阻力分布,并对膜污染物进行了解析,研究结果表明:不同跨膜压差条件下,活性污泥对超滤膜的污染机制不同,跨膜压差为20 kPa时膜污染速率最低;40~80 kPa范围内,膜污染速率、滤饼层与膜孔堵塞阻力上升速率在60 kPa时均达到最低;活性污泥主要造成滤饼层过滤阻力,其在总过滤阻力中占92%以上;分析滤饼层组分发现,松散结合型胞外聚合物是引起滤饼层污染的主要物质;膜孔中的有机污染物含量随过滤时间的延长而增加,且污泥代谢产物直接影响膜孔污染物组成。

A cross-flow membrane bioreactor(MBR)in constant-flux operation was adopted to investigate the impacts of activated sludge on ultrafiltration membrane fouling under different transmembrane pressures.The effect of activated sludge on ultrafiltration membrane fouling rate and membrane resistance distribution under transmembrane pressures of 20,40,60 and 80 kPa,were investigated,meanwhile,the membrane fouling pollutants were analyzed.The study results showed that,membrane fouling mechanisms induced by activated sludge were different according to the different transmembrane pressures,the lowest membrane fouling rate was obtained when the transmembrane pressure was 20 kPa.In the range of 40-80 kPa,the activated sludge under 60 kPa possessed the lowest membrane fouling potential,including the membrane fouling rate and the rising rate of cake layer resistance and pore blocking resistance.Activated sludge mainly induced cake layer formation,with the cake layer resistance accounted more than 92%of the total filtration resistance.The analysis results of the cake layer components showed that,the loosely bound extracellular polymer substance was the main matters cause the cake layer pollution;the content of organic pollutants in membrane pores increased with the prolonging of filtration time,and the metabolite of the sludge directly affected the pollutants components in the membrane pores.