自养硝化与异养反硝化污泥膜污染特性的对比  

Comparison of membrane biofouling of autotrophic nitrifying and heterotrophic denitrifying sludge

作　　者：王朝朝[1] 李军[1] 

机构地区：[1]北京工业大学建筑工程学院,北京100124

出　　处：《中南大学学报（自然科学版）》2013年第6期2629-2636,共8页Journal of Central South University:Science and Technology

基　　金：国家水体污染控制与治理科技重大专项(2008ZX07314-008)

摘　　要：以同步脱氮除磷连续流膜生物反应器小试稳定运行时的污泥为考查对象,采用序批式过滤试验对比考查硝化污泥与反硝化污泥的污染特性,并对不同电子供体下反硝化污泥的污染机理进行分析与探讨。研究结果表明:在25℃下乙酸作为电子供体下的反硝化速率(以VSS计)为13.8 mg/(g·h),高于乙醇的10.2 mg/(g·h)和甲醇的3.4mg/(g·h);反硝化污泥相对于硝化污泥溶解性微生物产物(soluble microbial product,SMP)中蛋白质类物质在<1 kDa和>100 kDa范围内含量的增多,成为导致污泥混合液中溶解性物质阻力增大的主要因素,从而增大溶解性物质在膜孔内部的堵塞的阻力,其中以甲醇为电子供体时的反硝化过程最为明显。反硝化过程污泥产生的胞外聚合物(extracellular polymeric substances,EPS)相对于硝化过程有所降低,且EPS中糖类与蛋白质类物质的相对疏水性的降低成为混合液中悬浮颗粒物质(suspend solids,SS)阻力降低的主要因素;硝化污泥与3种电子供体下产生的EPS相对分子质量分布上略有不同,但是傅里叶红外光谱(Fourier transform infrared spectroscopy,FT-IR)对EPS官能团的监测表明硝化过程与3种电子供体在反硝化过程中产生的EPS主要化学物质组成并没有发生变化,以乙酸为电子供体下反硝化过程后污泥的修正污染指数(modified fouling index,MFI)最小。A Batch filtration tests were carried out to investigate the membrane biofouling characterizations of nitrifying and denitrifying sludge from a continuous-flow nitrogen and phosphorus removal bench-scale membrane bioreactor under the stable operation. Biofouling mechanisms of denitrifying sludge by using different electron donors were also analyzed and discussed. The test results show that the denitrifying rate by using the acetic acid as the electron donor is 13.8 mg/（g·h）, higher than methanol 3.4 mg/（g·h）, ethanol 10.2 mg/（g·h） at 25℃; compared with nitrifying sludge, the protein of soluble microbial products from denitrifying sludges increases in the range of 〈 1 kDa and 〉 100 kDa, being the main factor for the increased resistance of soluble substances in the mixed liquor, thereby increasing the pore blocking resistance of soluble substances, and denitrification process by using the methanol as the electron donor is the most obvious. It is also found that the decrease of extracellular polymeric substances produced through denitrification processes and relative hydrophobicity of carbohydrate and protein substances becomes the main factor for the decreased resistance of SS fraction in the mixed liquor; the relative molecular mass distributions of extracellular polymericsubstances becomes slightly different after denitrification, but Fourier transform infrared spectroscopy of the functional groups of extracellular polymeric substances shows that the chemical composition of extracellular polymeric substances produced by nitrifying sludge and denitrifying sludge by using three different electron donors have not changed. The modified fouling index of denitrifying sludge by using acetic as the electron donor becomes the lowest one.

关 键 词：膜生物反应器 硝化与反硝化 修正污染指数 胞外聚合物 溶解性微生物代谢产物 

分 类 号：X703[环境科学与工程—环境工程]