tailieunhanh - Flocculation In Natural And Engineered Environmental Systems - Chapter 4

Trong thập kỷ qua đã có một sự nhấn mạnh nghiên cứu phối hợp về cơ cấu, giải quyết, và lưu trữ của trầm tích lơ lửng trong nước ngọt ven sông Cơ quan này công việc đã được công nhận tầm quan trọng của keo tụ và tập hợp (thuật ngữ được sử dụng thay thế cho nhau trong văn học) vận chuyển bùn cát ven sông quy trình, và những tác động đồng thời cho việc lưu trữ của cả hai trầm tích và trầm tích liên quan đến chất gây ô nhiễm. Trong khi các cơ chế và các yếu. | 4 The Composite Nature of Suspended and Gravel Stored Fine Sediment in Streams A Case Study of O Ne-eil Creek British Columbia Canada Ellen L. Petticrew CONTENTS Introduction. 71 Methods. 73 Study Area. 73 Field Methods. 74 Suspended Sediment Measurements . 74 Settling Chamber Measurements . 77 Infiltration Gravel Bags. 78 Visual Characterization of Aggregate Particles. 78 Results. 79 Discussion. 86 Fractal Concerns . 89 Conclusions. 90 Acknowledgments . 91 References . 91 INTRODUCTION In the past decade there has been a concerted research emphasis on the structure settling and storage of suspended sediments in freshwater riverine This body of work has recognized the significance of flocculation and aggregation terms which are used interchangeably in the literature in riverine sediment transport processes and the concomitant implications for the storage of both sediments and 1-56670-615-7 05 2005 byCRC Press 71 Copyright 2005 by CRC Press 72 Flocculation in Natural and Engineered Environmental Systems sediment-associated contaminants. While the mechanisms and factors regulating flocculation defined as the combination of two or more particles of mineral or organic material to create larger composite particles have been research interests in the marine literature for decades they were only reported as being significant in natural freshwater systems in the While the process of flocculation increases both the effective size of the particle and modifies its density it has been shown that the propensity for particle settling is influenced more by the particles altered size rather than its density or While the literature details the conditions or mechanisms which promote the flocculation and aggregation of sediments in rivers increased sediment concentrations increased collision encounters decreased shear velocities high ionic strength increased bacterial .