Acoustically enhanced ganglia mobilization in the presence of colloids

Due to their toxicity and persistence in the subsurface environment, dense non-aqueous phase liquids (DNAPLs) continue to be an important area of research for contaminated groundwater remediation technologies. New remediation techniques utilizing acoustic waves have recently received attention. However, these studies do not consider colloids, which are ubiquitous in groundwater aquifers, may act as mobile sorption sites for DNAPLs, or may be used in sonic cases for remediation themselves. The focus of this work was to investigate the effects of acoustic waves on colloid transport and deposition in porous media and the effects of colloids on NAPL ganglia dissolution and mobilization in the presence of acoustic waves. These effects have not previously been investigated to the knowledge of the author.;In Chapter 3, a series of packed-column experiments in the presence of acoustic' waves ranging in frequency from 0 to 150 Hz was performed to determine their effects on colloid transport. An analytical model was formulated to quantify the effects and a parametric study performed. Due to a number of inherent weaknesses in standard packed-column effluent analysis the mechanisms responsible for the observations could not be specifically addressed.;Chapter 4 details a new experimental method including a new apparatus design, photographic procedures, and quantification method aimed at overcoming the weaknesses in order to explore the mechanisms responsible for the observations.;In Chapter 5, the new method is employed in a series of packed-column laboratory experiments in order to increase our understanding of the mechanisms responsible for the observed effects. A number of possible mechanisms are included and discussed and new empirical mathematical models are suggested.;Finally, in Chapter 6, new etched-glass porous-media micromodels were constructed and utilized in experiments to explore the additional effects of adding colloid suspensions to NAPL dissolution/mobilization experiments with acoustic waves. The results presented are preliminary and directions for future research is discussed. More detailed and specific abstracts are included in each chapter.