Tracing pharmaceuticals in an integrated municipal plant for wastewater and organic waste treatment

The occurrence, removal and fate of 43 pharmaceuticals belonging to different therapeutic groups were studied in the various stages of a full scale municipal integrated treatment plant. Here the biological nutrient removal from municipal wastewater is operated in the water train, while the sludge treatment train provides the anaerobic co-digestion of the waste activated sludge (WAS) and the organic fraction of municipal solid waste (OFMSW), with the following separate short-cut nitrogen removal from the anaerobic supernatant. Wastewater (i.e. WWTP raw influent, biological reactor influent and effluent wastewater) and sludge (i.e. WAS, digestate of WAS and OFMSW, WAS from the separate biological treatment of anaerobic supernatant) samples, as well as sludge supernatants and suspended particulate matter samples, were analyzed in order to obtain more information on the fate of the selected pharmaceuticals during treatment. Particular attention was paid to the solid-liquid partitioning, since it is well known that the particulate fraction may include a high portion of the potential pollution load, even in the case of polar compounds such as pharmaceuticals. At the influent of the plant and the biological reactor, the suspended particulate matter was collected using an automatic sampler equipped with a polyvinylidene fluoride hollow- fiber submerged membrane module, specially designed for this purpose (Fatone et al, 2011). It allowed the analysis of concentrated samples that contained ca. 20 times more concentrated suspended particulates (i.e. 6-12 gSS L-1) than the commonly analyzed conventional composite samples from raw urban wastewater (i.e. 0.1-0.6 gSS L-1). The preparation and analysis of the samples were performed using high performance liquid chromatography coupled to a Hybrid Triple Quadrupole/Linear Ion trap mass spectrometer according to the previously developed multi-residual methodologies for analysis of pharmaceuticals in wastewater and sludge samples (Jelic et al., 2009)