High-resolution mass spectrometry: an innovative tool for characterizing wastewater facilities

High Resolution Mass Spectrometry (HR-MS) is a tool recently used for environmental chemical analysis. Based on the generation of the chemical signatures of a sample and not on the analysis of targeted compounds, this technique could improve the characterization of the effluents and the understanding of the processes involved for the removal of organic contaminants in sanitation systems. Indeed, it opens access to a large amount of information, which, after appropriate statistical processing, makes it possible to compare works, to highlight and to identify 'new' contaminants previously not considered. This study proposes the use of HR-MS to compare matrices from two stations (Seine-Center and Seine-Aval) via a global approach. The exploration of the data generated during this work made it possible to evaluate the relevance of the use of the HR-MS to evaluate sanitation systems. The analysis of the chemical fingerprints showed a similarity between the sludge at the beginning of centrifugation and digestion, which tends to show a homogeneity of the quality of the sludge produced in the two stations. It also highlighted the presence of physicochemical and/or biological processes during digestion which strongly modify the nature of the sludge at the end of the process. The identification of some of the compounds shows that the most discriminant belong to different classes of surfactants, mainly quaternary ammoniums (cationic surfactants) and linear alkylbenzene sulfonates (LAS). It would be interesting to improve this non-targeted approach by developing new statistical tools and implementing databases, in order to make the HR-MS approach a tool for monitoring the quality of waste. (authors)