Design and Implementation of Pilot Scale Surfactant Washing/Flushing Technologies including Surfactant Reuse

Chemicals with low solubility, volatility, and biodegradability can be very hard to treat in soils. These chemicals may however by addressed by surfactant supplemented technologies. PCBs are a prime example of difficult chemicals and were used frequently in the studies. The surfactant enhances the solubility of the chemicals, therefore effecting their desorption and more efficient treatment. ECKENFELDER INC. has completed laboratory scale experiments simulating in situ/ex situ surfactant treatment of various types of chemicals, singly and in combination, and has built a pilot scale unit for the surfactant treatment of contaminated soils. The pilot scale system includes surfactant recycle and reuse of an anionic surfactant, sodium dodecyl sulfate, SDS. The resultant volume of contaminants is reduced many fold, thus consistent with US regulatory requirements as well as reducing final disposal costs. In addition to the pilot scale unit, studies were made on the impact of non equilibrium (e.g., desorption, diffusion, etc.) effects on treatment efficiency as well as developing “real time” chemical analyses of PCBs in SDS solution. A mathematical model has also been developed which assists with design/performance assessments.