Abstract: Models for prediction of exposure of sewage treatment plants (STPs) are an important means of assessing fate of chemicals in the environment. Investigations and measurements were performed of parameters of the treatment technologies, sewage properties and environmental conditions of some typical STPs in China.Results show that the concentrations of BOD₅ and suspended solids in inflows of the STPs in China are generally lower than those of the STPs in the EU. Fates for 2,6-di-tert-butylphenol, 2,4-di-tert-amyl phenol and 1-naphthol were compared using the EU SimpleTreat model between scenario parameters of China and the EU. It was found that in China of the three chemicals, a relatively low percentage entered into sludge and a quite high percentage discharged into waterbody, which indicates that pollution risk of the water environment is quite high. Sensitivity analysis of the model shows that the BOD₅ and SS in inflow of STPs, organic carbon content in activated sludge and environment temperature are the main factors affecting fate of the chemicals.

Key words: sewage treatment plant, model, chemical, exposure, predict