厌氧膜生物反应器中亲疏水性有机物的膜污染特征

采用树脂吸附脱附的方法对厌氧膜生物反应器（AnMBR）中溶解性微生物代谢产物（SMP）的6种亲疏水性有机物进行了分离，其中，亲水中性物质是SMP的主要成分，占总有机物的74.84%.多糖、蛋白质和腐殖质类物质在亲疏水性有机物中均有分布.采用恒压死端过滤的方式对比分析了6种亲疏水性有机物的微滤特性，发现在TOC浓度相同的条件下，亲水性碱（HIB）是造成膜通量下降最快的物质，其次是亲水中性物（HIN）和疏水性酸（HOA），膜通量下降速率与有机物平均粒径呈指数相关关系（R²=0.9965）.采用过滤模型对微滤过程进行拟合，HOA、HIN和HIB的过滤过程分别符合标准堵塞模型、中间过滤模型和滤饼过滤模型的特征，与其粒径分布特征相对应.试验进一步对比了亲疏水性有机物污染层的可逆性，结果表明HIN造成的膜污染不易通过物理反冲洗得到恢复.

Fouling of microfiltration membranes by hydrophilic and hydrophobic organic fractions in Anaerobic membrane bioreactors

In this study, the soluble microbial product (SMP) in an anaerobic membrane bioreactor (AnMBR) was fractionated into six kinds of hydrophilic or hydrophobic fractions through a sequence of adsorption/desorption using DAX-8, Amberlyst^® 15 and Amberlyst^® A21 resins. The hydrophilic neutrals (HIN) was found to be the major component in the SMP, accounting for 74.84% in terms of the total organic carbon (TOC). Polysaccharides, protein, and humic substrates were identified in all the six types of organic fractions. In order to further understand the membrane fouling mechanism of different organic fractions, the fouling propensity was evaluated through a series of batch microfiltration experiments with a stirred dead-end filtration cell under constant pressure. The membrane suffered a quickest flux decline with the hydrophilic base (HIB) solution, next came the HIN solution and hydrophobic acid (HOA) solution. An exponential correlation was found between the flux decreasing rate and mean particle size of the organics (R²=0.9965). Classic filtration models were employed for further analyses of the fouling evolution. The standard blocking, intermediate blocking and cake filtration models were found to fit the HOA, HIN, and HIB filtration behaviors, respectively. The irreversibility of membrane fouling caused by different organic matter was also investigated. The HIN-based fouling was found to be more difficult to be cleaned than other fouling types.