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Hạt tổng hợp là một quá trình phức tạp ảnh hưởng bởi hóa học khác nhau, thể, và thủy động lực học điều kiện. Nó là mối quan tâm cho sự hiểu biết, mô hình hóa, và thiết kế trong nước tự nhiên, thiết kế và hệ thống xử lý nước thải. | 5 Effects of Floc Size and Shape in Particle Aggregation Joseph F. Atkinson Rajat K. Chakraborti and John E. VanBenschoten CONTENTS 5.1 Introduction. 95 5.2 Background. 97 5.2.1 Fractal Aggregate Properties . 97 5.2.2 Model Development. 99 5.2.2.1 Conceptual Fractal Model of Aggregation. 101 5.3 Experimental Setup. 103 5.3.1 Image Analysis. 103 5.3.2 Materials and General Procedures . 105 5.3.2.1 Experiment Set 1 . 106 5.3.2.2 Experiment Set 2 . 106 5.3.2.3 Experiment Set 3 . 107 5.4 Results and Discussion. 109 5.4.1 Observations and Analysis of Data. 109 5.4.1.1 Coagulation-Flocculation. 109 5.4.1.2 Particle Size and Shape. 110 5.4.1.3 Density and Porosity . 113 5.4.1.4 Collision Frequency Function. 113 5.4.1.5 Settling Velocity. 116 5.5 Conclusions and Recommendations . 117 Nomenclature. 118 References . 119 5.1 INTRODUCTION Particle aggregation is a complex process affected by various physical chemical and hydrodynamic conditions. It is of interest for understanding modeling and design in natural and engineered water and wastewater treatment systems. In natural aquatic 1-56670-615-7 05 0.00 1.50 2005 byCRC Press 95 Copyright 2005 by CRC Press 96 Flocculation in Natural and Engineered Environmental Systems systems such as lakes rivers and estuaries particle aggregation is important because it controls the fate of both the particles themselves as well as potentially hazardous substances adsorbed to the particles.1-5 In water and wastewater treatment flocculation is used to produce larger aggregates that can more effectively be removed from the treatment stream by sedimentation and filtration.6-8 The growth of aggregates depends on the relative size of the colliding particles or clusters of particles their number density surface charge and roughness local shear forces and the suspending electrolyte. Specific factors that affect aggregation include coagulant dose mixing intensity particle concentration temperature solution pH and organisms in the suspension.3 7 9 .
