厌氧膜生物反应器处理市政污水中试系统中溶解性微生物产物特性及膜污染行为

Characteristics of soluble microbial products and membrane fouling behavior in a pilot anaerobic membrane bioreactor for municipal wastewater treatment

溶解性微生物产物(soluble microbial products,SMP)引起的膜污染是限制厌氧膜生物反应器(anaerobic membrane bioreactor,AnMBR)工程化应用的主要原因。基于大型中试AnMBR污水处理工程,考察了SMP的物质组成及荧光特性,解析了膜及膜上污染物对SMP的截留特征,揭示了SMP中不同有机组分的膜污染行为及污染层特征。结果表明:AnMBR高效稳定运行时SMP平均质量浓度为(119.3±10.0)mg·L^(−1)(以溶解性有机碳计),主要是分子质量(molecular weight,MW)≥100000 Da(77.3±8.1)%的大分子,组分为木质素及富羧基脂环分子类(45.2%)、蛋白质及氨基糖类(26.1%)和脂质类(14.0%)。膜及膜上污染物对SMP具有较高的截留率(83.7±5.4)%,其中MW≥100000 Da的大分子截留率达到98.8%,其他中小分子截留率为10%~26%。耗散型石英晶体微量天平分析发现大分子在膜界面吸附量高,是SMP中引起膜污染的主要组分;中小分子(MW<100000Da)形成的膜污染层更密实,导致了膜通量快速降低和不可逆污染。本研究深入揭示了AnMBR中SMP特性及膜污染行为,为高效膜污染控制方法开发提供参考。

The membrane fouling caused by soluble microbial products(SMP)is the main reason limiting the engineering application of anaerobic membrane bioreactor(AnMBR).Based on a large pilot-scale AnMBR for wastewater treatment,this study investigated the compositions and fluorescence characteristics of SMP,analyzed the SMP interception characteristics of the membrane and membrane foulants,and revealed the membrane fouling behaviors and characteristics of the fouling layer formed by different organic components of SMP.The results showed that the average concentration of SMP in AnMBR was(119.3±10.0)mg·L^(−1)(based on dissolved organic carbon)during the stable operation stage.Most of the SMP were macromolecules with molecular weights higher than 100000 Da(77.3±8.1)%.The compositions of SMP contained lignin and carboxyl-rich alicyclic molecules(45.2%),protein and amino sugars(26.1%)and lipids(14.0%).The membrane and membrane foulants exhibited a high SMP interception rate(83.7±5.4)%,of which the macromolecules interception rate reached 98.8%,while that the low and medium molecules interception rates ranged from 10%to 26%.Quartz crystal microbalance with dissipation monitoring indicated that macromolecules with high adsorption capacity at the membrane interface were the main components of SMP that caused membrane fouling.The fouling layer formed by low and medium molecules was dense,leading to a rapid decline in membrane flux and irreversible membrane fouling.This study revealed the characteristics and membrane fouling behaviors of SMP in AnMBR and provides a reference for the development of efficient membrane fouling control methods.