Foam Fractionation of Rinsing Waters Containing Surfactants

Foam fractionation (FF) can be utilized to separate the surfactants from rinsing waters of surfactant production plants and recover a concentrated surfactant solution. By bubbling air through the solution the surfactants are removed with the foam, which has a high surface to liquid volume ratio. The foam, once destroyed, has a high concentration of surfactants and represents a usable product. At concentrations above 1 g/L a multi-stage treatment of the effluent leads to an increase both in the removal degree and enrichment when the operating parameters are correctly chosen for each stage. Countercurrent operation with foamate recycle makes it possible to increase the enrichment significantly.