Fate of surfactants in activated sludge waste water treatment plants

An extensive monitoring programme was conducted in the Netherlands to determine the environmental concentrations of the main types of surfactants, including linear alkylbenzene sulphonate (LAS), alcohol ethoxylates (AE), alcohol ethoxy sulphates (AES) and soap. The study was conducted in seven representative Dutch sewage treatment plants. The measured effluent concentrations were used to predict the 90th percentile river water concentrations for the surfactants using an in-stream removal rate of 0.70 day(-1). The predicted exposure concentrations (PEC) in the river water were 3.7 mu g/l for LAS, 0.5 mu g/l for AE, 1.2 mu g/l for AES and 20 mu g/l for soap.