Non-target screening in treated wastewater reuse: a new tool for process evaluation ?

An analytical set-up was optimized aimed at detecting a wide range of non target compounds in terms of polarities, namely from low/medium polar to very polar/ionic. Such an analytical strategy was applied for monitoring both the influent and the effluents of the step included in a pilot-scale experimental set-ups for wastewater reuse. The set-ups include sequential biofiltration with intermediate aeration at different empty bed contact time (EBCT) or with an intermediate ozonation. The non target screening was finalized to better tailor the wastewater reuse procedure. The comparison of the different treatment steps was performed based on (i) comparing the removal efficiency of suspect CECs identified in the samples, (ii) number of overall trends (compounds whose peak area along the treatment steps decreases, increases or remains steady) and (iii) by a multivariate analysis employing the principal component analysis (PCA). The investigation performed was able to assess the behavior of compounds detected as suspect (e.g. metformin) along the experimental set-up based on multiple treatment barriers. In addition, non target screening allowed to compare the effluents in terms of the four classes of compounds and to obtain relevant results to be conveniently used for the assessment strategies of the experimental wastewater reuse set-ups.