Assessment of selected micropollutants and the effect of rain events in wastewater treatment plant and its receiving water body

Abstract

Frequent detection of micropollutants in municipal wastewater raise the concern of these non-regulated pollutants and their adverse effects on aquatic life. The lack of comprehensive investigation and regulations in water policies regarded to micropollutants behavior may lead to the contamination of water resources. In contemplation of extending the groundwork for future water policies, an assessment of the behavior of micropollutants such as pharmaceuticals, industrial chemicals, personal care products and pesticides have been accomplished. Observation of the diurnal behavior, effect of rain events and combined sewer overflows, evaluation of comportment of conventional parameters and heavy metals with micropollutants and an estimation of average diurnal load per capita have been the objectives of this study. The influent and effluent of the wastewater treatment plant of Herbolzheim, its receiving water body and the combined sewer overflows in its catchment area have been investigated. In regard to non-polar substances, gas chromatography and mass spectrometry has been applied, whereas high performance liquid chromatography was used for polar micropollutants. Comparative demonstration of conventional parameters affirms the reliability of results to be compared with the micropollutants. Influent of Triclosan seems to follow a similar pattern as turbidity; moreover, the fluctuation of the ammonium and pharmaceuticals appears to be resemblance due to the same source of diffuse. Furthermore, the elimination percentage for different substances ranges from no degradation for substances such as Carbamazepine, to almost complete removal of 99% for the Ibuprofen. Correlation between the spectral absorption coefficient and the pharmaceuticals as well as turbidity and Triclosan seems to be strong; additionally the strength of the correlation among ammonium and the pharmaceuticals is related to the frequency of consumption of pharmaceuticals. The average effluent concentrations of this study in comparison with other studies in Europe and the state of Baden-Württemberg have been introduced. Influent load fluctuations seem to be almost constant for several substances, hence an average estimation of influent load per capita has been investigated and compared with other studies. Comportment of heavy metals and metals such as potassium and micropollutants is evident. Ultimately, the concentrations of micropollutants in combined sewer overflows in multiple cases are higher than the effluent and even of the influent of the wastewater treatment plant, which implies the necessity of the treatment before discharge into the water body. Enforcement of regulations will enhance the protection of water resources and diminish the pollutants from the diffuse sources.