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生物膜作为微生物的载体,其组成、结构对生物膜反应器的工作性能具有重要影响。以城市污水处理厂和实验室混合处理系统两种典型的生物膜为对象,利用荧光染色和FISH技术研究生物膜中EPS与微生物的分布特征,同时考察不同提取方法对生物膜中EPS含量的影响。结果表明,两种生物膜均呈现典型的非均相体系,内部存在非均一的空洞和孔隙;EPS呈网状结构,构成生物膜的骨架,微生物填充其中;生物膜表层由于基质充足,微生物数量较高,而在生物膜内部,由于基质扩散限制和内源呼吸作用,微生物数量较低;生物膜表层主要为异养菌,硝化菌主要生长在内层;EPS中蛋白质的含量沿生物膜深度方向逐渐减少,而多糖含量则与之相反。相比于实际生物膜,实验室生物膜厚度较大,表面粗糙,VSS/SS值较高,耗氧速率也较大。各提取方法提取的EPS含量由多到少依次为:甲醛+Na OH>加热>CER。
Biofilm as a carrier of microorganisms, the composition and structure of the biofilm reactor performance has an important impact. Two typical biofilms from urban sewage treatment plant and laboratory mixed treatment system were used as targets. The distribution characteristics of EPS and microorganisms in biofilm were studied by fluorescence staining and FISH. Meanwhile, the effects of different extraction methods on EPS content in biofilm . The results showed that both biofilms showed a typical heterogeneous system with heterogeneous voids and pores inside. EPS was in a network structure and formed the skeleton of biofilm, which was filled with microorganisms. The surface of biofilm with abundant matrix, But in the biofilm, the number of microorganisms was lower due to the limitation of matrix diffusion and endogenous respiration. The surface of biofilm was mainly heterotrophic bacteria, while the nitrifying bacteria mainly grew in the inner layer. The protein content in EPS was along the depth of biofilm The direction of decrease, while the polysaccharide content is the opposite. Compared with the actual biofilm, laboratory biofilm thicker, rough surface, higher VSS / SS value, oxygen consumption rate is also larger. The content of EPS extracted by each extraction method is as follows: formaldehyde + Na OH> heating> CER.