Please use this identifier to cite or link to this item:
Title: Sediment-toxic substance interaction modelling
Authors: Wan, Yiu-por
Keywords: Hong Kong Polytechnic University -- Dissertations
Sediment transport
Hazardous wastes -- Transportation
Water quality
Groundwater -- Quality
Issue Date: 2003
Publisher: The Hong Kong Polytechnic University
Abstract: Water quality models with analytical solutions are developed to simulate the transport of toxic substances in different aquatic environments. The models take into account both the physical transport processes such as the transport by water flows and dispersion mixings, and the chemical processes such as the sorption kinetics between the toxic substances and the sediment. Analytical forms in this research are being derived because analytical solutions can act as fast predicting tools in relatively simple cases. They also offer fundamental insights into the contributions of particular physical or chemical parameters to the transport process. However, in order to solve the models analytically, the governing systems must be formulated in relatively simple forms, while still retaining sufficient physics and chemistry to be realistic. In accordance with the above requirements, a one dimensional, time varying governing system has been studied and solved analytically. The vertical axis z is chosen as the controlling dimension in the governing system in order to include the settling and the resuspension of sediment and toxic substances in the water column. An instantaneous equilibrium of sorption kinetics between dissolved and particulate toxic substances is assumed and a governing equation is written in terms of the total toxic substance concentration. The governing system is further studied by assuming two different flow conditions (constant and parabolic distribution of the turbulent mixing coefficient) and the equilibrium distribution of suspended sediment in the whole transport process. Three analytical water quality models with constant or specific coefficients in the governing equations are developed based on the governing system. The analysis of different parameters in the governing system is carried out to identify the parameter ranges under which the transport of toxic substances can be modeled by the developed models. Analysis is also conducted to identify the effects of particular parameters on toxic substance transports. Since the particulate toxic substances has an additional downward motion due to the particle settling. The overall concentration is smaller for cases that have a larger fraction of toxic substances in the particulate forms. Thus, a larger partition coefficient and settling velocity or a smaller mixing coefficient leads to lower concentrations. Finally, three cases studies are presented to demonstrate the applications of the developed models for toxic substance transports and also in other areas. It is found that the models are also useful for simulating the transport of sediment in the water column and of chemicals in soil layers.
Description: xxi, 221 leaves ; ill. ; 30 cm.
PolyU Library Call No.: [THS] LG51 .H577M CSE 2003 Wan
Rights: All rights reserved.
Appears in Collections:Thesis

Files in This Item:
File Description SizeFormat 
b17330713_link.htmFor PolyU Users 162 BHTMLView/Open
b17330713_ir.pdfFor All Users (Non-printable) 6.12 MBAdobe PDFView/Open
Show full item record
PIRA download icon_1.1View/Download Contents

Page view(s)

Last Week
Last month
Citations as of Feb 18, 2019


Citations as of Feb 18, 2019

Google ScholarTM


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.