Surfactant-Induced Changes of Water Flow and Solute Transport in Soils
Abstract
Surfactants are present in the environment due to agricultural practices such as irrigation with wastewater, biosolid soil amendments, and/or environmental engineering remediation. Furthermore, surfactants occur widely in soils due to the application of pesticides in surfactant solution sprays, or the application of surfactants as soil wetting agents. Surfactants, because they are amphiphilic and impact the surface tension of aqueous solutions and the contact angle between aqueous and solid phases have the potential to influence water flow in porous media and the physicochemical properties of soils. The objective of this study was to assess the impact of surfactant on the soil infiltration process. Four different soils were used in this study: two sandy loam soils (Lewiston and Greenson series) and two loamy sand soils (Sparta and Gilford series). Rainfall was simulated to flow through different columns filled with the four different types of soil and effluent samples were collected at the end of each column. Each type of soil had two columns, one with a non-ionic surfactant Aerosol®22 at twice the critical micelle concentration, in the rainfall solution and one without. A conservative tracer, potassium bromide, was added to all rainfalls to monitor the infiltration process in soil. Tracer breakthrough curves were used to characterize flow in soils. Flow rates were also recorded for each soil. The presence of surfactant decreased the flow rate by a significant amount in most soil types. The decrease in flow rate can be attributed to the effects on the soil properties of hydraulic conductivity and soil aggregates. A decrease in pore space from the swelling of the soil particles can decrease the hydraulic conductivity. The properties in surfactants also decrease the surface tension and therefore soil particles are able to be dislodged from soil aggregates and cause potential soil clogging.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.H21C1411K
- Keywords:
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- 1805 Computational hydrology;
- HYDROLOGYDE: 1847 Modeling;
- HYDROLOGYDE: 1865 Soils;
- HYDROLOGY