Surfactant-Induced Hydraulic Conductivity Changes in Clay Soils Primary Researchers: Miguel Arias and Danielle Farrell Advised by: Dr. Kevin Gardner Over the last twenty years, contamination of soil and groundwater by crude oil and refined petroleum products has gained national attention as problems have been discovered across the country. Groundwater contamination is of special concern, as approximately 50% of all drinking water supplies come from ground water sources. As concern over petroleum contamination in soils has increased, so has interest in new, low cost, effective methods to remediate petroleum-contaminated soil. One method which has been gaining increased attention over the last few years is the use of surfactants to improve the performance of soil washing and/or soil flushing operations. However, a major concern in the use of surfactants, especially with in-situ applications, is that it has long been known that the use of surfactants can result in a significant change in the hydraulic conductivity of porous media, either by changing intrinsic permeability or fluid characteristics. Any change in hydraulic conductivity during a soil washing operation can have deleterious effects. If hydraulic conductivity drops, the soil washing operation will become less efficient and more costly. If the effect is localized, it may mean that surfactant aided soil-washing is completely ineffectual. Conversely, if the permeability or hydraulic conductivity is increased unexpectedly, the result can be a further spreading of the contaminant plume and an exacerbation of the problem, not to mention the increased liability associated with contaminant spread. This research is focusing on investigating the underlying mechanisms by which hydraulic conductivity is altered, particularly in soils containing clays. In general, the possible mechanisms, some of which have been demonstrated in certain circumstances, are as follows. Direct physical effects (on either fluid characteristics or the porous media); Viscosity Effects Reduction of Contaminant Clogging Enhancement of Contaminant Clogging Formation of Macroemulsions Adsorption of Surfactants Destruction of soil aggregate and production of fines (non-clay soils) Decreased Aggregate Stability and Release of Fines Increased Aggregate Stability and Agglomeration of Fines Surfactant-clay interactions Clay Swelling Dispersion of Clay Particles Induced, secondary chemical reactions Mineral Dissolution and Piping Mineral Precipitation CWRU Department of Civil Engineering Main Menu | Sitemap | Department Activities | On-Campus Menu Communication Click to request a Graduate | Undergraduate Application Form. Click to get in touch with a Graduate | Undergraduate Student. Click to Schedule a Tour of the Department.