反硝化生物滤池生物膜胞外聚合物空间分布特征

Spatial distribution characteristics of extracellular polymeric substances in a denitrification biological filter

研究了上流式反硝化生物滤池(DNBF)生物膜胞外聚合物(EPS)的空间分布特征,EPS的空间结构及组成对基质在生物膜内的传质作用有较大的影响,进而影响反硝化反应的进程和DNBF的脱氮效果。结果表明,沿水流方向生物膜EPS含量呈先升高后降低的变化趋势,在滤料层中间段为最高(56.14 mg·g^(-1))。将生物膜EPS分为悬浮型与附着型(包括溶解型、松散附着型和紧密黏附型)进行分层分析,发现每个分层的蛋白质含量均高于多糖含量;悬浮生物膜EPS中的多糖含量高于其他分层;溶解型和松散附着型生物膜EPS中的多糖含量高于紧密黏附型生物膜EPS。三维荧光光谱分析表明,悬浮生物膜EPS中所含主要物质为溶解性微生物分解副产物类,附着生物膜中,溶解型和松散附着型生物膜EPS包含酪氨酸类、色氨酸类蛋白质以及溶解性微生物分解副产物类蛋白质,紧密黏附型生物膜EPS主要包含溶解性微生物分解副产物类蛋白质。傅里叶红外光谱解析表明,羧基、酰胺基、羟基等是EPS中的主要基团。

Spatial distribution characteristics of extracellular polymeric substances（EPS） in a lab-scale up-flow denitrification biological filter（DNBF） were investigated.The spatial structure and composition of EPS had very significant impacts on not only the mass transfer in the biofilm,but also the process of denitrification and nitrogen removal by the DNBF.The results showed that the total EPS concentration increased along the water flow path,reached 56.14 mg·g^（-1）in the middle of filtration,and then decreased.The total EPS were divided into two layers of captured biofilms EPS（CB-EPS） and attached biofilms EPS（AB-EPS）,the latter of which was divided further into 3 sublayers of soluble EPS（AB-SEPS）,loosely bound EPS（AB-LB）,and tightly bound EPS（ABTB）.Each EPS layer had higher concentrations of proteins（PN） than of polysaccharides（PS）.The PS content in the CB-EPS was higher than it was in the AB-EPS,and the PS concentrations in the AB-SEPS and AB-LB were both higher than they were in the AB-TB.The results of three-dimensional fluorescence spectroscopy showed that soluble microbial by-product-like organic compounds dominated the CB-EPS and AB-TB,whereas tyrosine-and tryptophan-like aromatic proteins and soluble microbial by-product-like substances dominated the AB-SEPS and AB-LB.Additionally,carboxyls,amides,and hydroxyls were the major functional groups of the EPS as determined from Fourier infrared spectra.