Permeability changes by surfactant solution: an experimental study to represent wastewater loss from sewers to saturated soil

Leakage of wastewater from sewer lines may result in contamination of soil and groundwater. The widespread use of detergents is causing relatively high concentrations of surfactants in wastewater. We studied the effects of surfactants on the infiltration process of wastewater through soil. To that aim, in a laboratory experiment three micro-pore glass filters were installed. A laboratory wastewater substitute was created by adding a commercially available detergent to degassed tap water producing surfactant concentrations of 100, 200 and 400 mg l(-1). Rapid changes in permeability after using the surfactant solution were detected. These were further examined during a process of washing the glass filters with water. The experimental results indicated that changes in permeability were induced by significant adsorption of surfactant molecules on the solids surfaces and thus reducing the size of the pores. Higher levels of permeability changes were detected for higher surfactant concentrations. Additionally, the efficiency of washing process of an adsorbed surfactant molecular layer at the pore surfaces was greater that before the critical micelle concentration.

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