引黄滴灌水源中泥沙表面附生生物膜的分形特征

Structural and fractal characteristics of biofilm attached on surfaces of sediments in Yellow River for drip irrigation

为了解决灌水器堵塞这个制约引黄滴灌技术应用和推广的关键问题,联合运用扫描电镜测试法和分形理论对黄河泥沙颗粒表面形貌进行了分析,结果表明:黄河泥沙颗粒表面形貌表现为以固体颗粒、微生物及其分泌的黏性胞外聚合物形成的复杂生物膜结构.黄河泥沙颗粒表面具有显著的分形和多重分形特征,简单分形维数虽然能从整体上表征颗粒物表面形貌的复杂性与不规则性,但未能刻画颗粒物局部奇异性的微观特征,而多重分形谱可以定量描述这种复杂泥沙颗粒形貌特征.黄河泥沙借助其巨大的表面积,吸附了大量的微生物,微生物分泌的胞外聚合物质量浓度高达276.08~360.68 mg/L,这就要求在控制引黄滴灌系统灌水器堵塞时,需要从以往单纯考虑泥沙颗粒物本身转变为综合考虑泥沙颗粒和微生物的耦合作用,寻求更为有效的堵塞控制策略.

Drip irrigation with Yellow River water has become an important way to solve water shortage. However,emitter clogging is a major problem for extending drip irrigation. The scanning electron microscope( SEM) technology and fractal theory were used to analyse the surface topography characteristics of sediment particles in the Yellow River. The results showed that there was a complex biofilm on the surface of sediment particles,which consisted of solid suspended particles,microorganism and extracellular polymers( EPS). The surface topography of sediment particles expressed the fractal and multifractal characteristics,while the multifractal singularity spectrum was more suitable to characterize the complex surface topography of sediment particles. With its huge surface area,a large amount of microorganism could be adsorbed on the sediment surface in the Yellow River,and the extracellular polymers secreted by microorganism was up to 276. 08- 360. 68 mg /L. Innovative or novel control strategies need to be established for emitter clogging of drip irrigation with Yellow River water. The sedimentparticles and the interaction between sediment particles and microorganism should both be considered to seek more effective methods to control emitter clogging.