Huiming Zhao, Hongwei Fang, Minghong Chen
Department of Hydraulic Engineering, State Key Laboratory of Hydro Science and Engineering, Tsinghua University, Beijing, People's Republic of China.
Scanning. 2011 Nov-Dec;33(6):437-45. doi: 10.1002/sca.20247. Epub 2011 Jun 9.
Sediment flocculation is a critical component for the understanding of cohesive sediment dynamics. Traditionally, the referred study has largely been devoted to forming mechanism, influencing factors and physicochemical sediment conditions of all kinds of organic-flocculation and inorganic-flocculation. However, during the last decade, the bioflocculation of sediment by biological activity has been given increasing attention. But most studies have focused on the interrelations between biological and sedimentological variables. With the assistance of a newly developed field kit and correlative microscopy (which includes environmental scanning electron microscopy and confocal laser scanning microscopy), this article begins to bridge the resolution gap between sediment particles and biological activities as well as its metabolic products biofilm, in order to better understand the role of polymeric material biofilm in floc ultrastructure and outward floc behavior of bioflocculation sediment. Results have demonstrated that bioflocculation sediment was observed to be composed of complex networks of biofilm and appeared to be of complicated physical floc structures. The biofilm was found to embed particles and permeate the void space, representing the dominant physical bridging mechanism of the flocs and contributed to the extensive surface area, architecture characteristics, and mechanical properties of bioflocculation sediment.
沉积物絮凝是理解粘性沉积物动力学的关键组成部分。传统上，相关研究主要致力于各种有机絮凝和无机絮凝的形成机制、影响因素及物理化学沉积物条件。然而，在过去十年中，生物活动对沉积物的生物絮凝作用越来越受到关注。但大多数研究集中在生物学变量与沉积学变量之间的相互关系上。借助新开发的现场工具包和相关显微镜技术（包括环境扫描电子显微镜和共聚焦激光扫描显微镜），本文开始弥合沉积物颗粒与生物活动及其代谢产物生物膜之间的分辨率差距，以便更好地理解聚合物材料生物膜在生物絮凝沉积物的絮体超微结构和向外絮体行为中的作用。结果表明，观察到生物絮凝沉积物由复杂的生物膜网络组成，且似乎具有复杂的物理絮体结构。发现生物膜嵌入颗粒并渗透孔隙空间，这是絮体主要的物理桥接机制，并有助于生物絮凝沉积物的广泛表面积、结构特征和机械性能。
