The contamination of groundwater and soils has been a big issue of great interest and importance to human health. When organic compounds from leaking underground storage tanks or accidental spills on the surface infiltrate into the subsurface environment, they migrate downward through the unsaturated zone. These contaminants are dissolved into groundwater and move with groundwater flow. Thus, there is a need for remediation technologies. Air sparging is relatively cost-effective, as well as an efficient and safe technique for recovering organic contaminants in the subsurface. This technique introduces air into the subsurface system to enhance the volatilization and bioremediation of the contaminant in the groundwater system. In this operating system, the movement of air phase can take place either as a continuous air phase or as discrete air bubbles. However, the present research focused on continuous air phase assumption and mass balance equations of individual phases rather than taking into account the movement of air bubbles and colloidal particle capture on discrete air-water interface. Generally colloidal particles are treated as suspended particles in the water, so the hypothesis is that the rising air bubble can collect the particles and transport them up to the water table where the pump extracts the dirty bubbles from the groundwater system to the processing unit on the ground surface. This dissertation developed a pore-scale study to model the migration of discrete air phase in the presence of colloidal particles captured on the air-water interface. The model was based on the pore-scale balance equation for forces acting on a bubble rising in a porous medium in the presence of colloids. A dimensional analysis of the phenomenon was also conducted to provide a more generalized methodology to evaluate the effect of individual forces acting on an air bubble. The results indicate that the proposed model can predict the terminal velocity of a rising bubble without or with colloidal particles and provide the effect of numbers of colloidal particles, properties of colloidal particles, and solid grain size. The results showed that the terminal velocity of a discrete bubble was affected by the attachment of particles on a bubble, and then the volatile organic compound (VOC) removal rate was changed by the various radii of a bubble and the number of colloidal particles on a bubble.

The aim of this research is to build up the model of trace metal phase speciation in Erh-Jen estuarine. Colloidal species were separated from the dissolved fraction by using cross-flow filtration technique. This allowed us to study the distribution of trace metal¡¦s phase speciation and the relationships between: (1) seasonal variation and phase speciation of trace metal; (2) stational variation and phase speciation of trace metal; (3) the concentration of total and and speciations; (4) the prodution and removel of speciation in different salinity; (5) the flocculants and phase speciation of trace metal. The results will supply abundant information about colloidal metals that should be great benefit to the study of metal speciation of Taiwan waters in the future. It is seriously polluted by trace metals in Erh-Jen estuarine. Iron has the highest concentration in river water, followed by nickel¡A manganese¡A zinc and copper. Station 3 which is located on San-Yen-Kung river is the most polluted. Zinc, copper and iron exist in particulate phase predominately. Particle and truly dissolve phase are the major species of TOC¡Bmanganese and nickel. Contents of all the metals and TOC have significant linear correlation with their major species. Zinc, copper and iron are found predominantly in colloidal fraction(1 kD~0.45£gm), averaging 54.9 ¡Ó19.3 %, 75.6 ¡Ó12.3 % and 72.5 ¡Ó28.0 %, respectively, of the filter-passing pool. TOC, manganese and nickel, resides primarily in the truly dissolved phase , averaging 63.2 ¡Ó11.5 %, 95.1 ¡Ó3.3 % and 72.0 ¡Ó23.9 %, respectively, of the filter-passing pool. The linear correlation between salinity and TOC, zinc, copper, manganese, nickel and iron are not significant in this study.

Thesis (Ph. D.)--University of Alberta, 2009. / Title from PDF file main screen (viewed on Nov. 27, 2009). "A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Department of Mechanical Engineering, University of Alberta." Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 143-148).

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2002. / Includes bibliographical references (leaves 57-60). Also available in electronic version. Access restricted to campus users.

Thesis (M.S.)--Ohio State University, 1964. / Includes bibliographical references. Available online via OhioLINK's ETD Center

Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 164-170).

Thesis (Ph. D.)--Lehigh University, 2004. / Includes vita. Includes bibliographical references (leaves 111-116).

Thesis (Ph. D.)--Lehigh University, 2003. / Includes vita. Includes bibliographical references (leaves 164-170).

Thesis (M.S.)--University of Delaware, 2009. / Principal faculty advisor: Yan Jin, Dept. of Plant & Soil Sciences. Includes bibliographical references.