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Browsing by Author Kaegi, R.

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Quantification of anthropogenic and geogenic Ce in sewage sludge based on Ce oxidation state and rare earth element patterns

Authors: Gogos, A.; Advisor: -; Participants: Wielinski, J.; Voegelin, A.; Kammer, F.V.D.; Kaegi, R. (2020)

Based on the assumption that the industrially used Ce is free of (most) other REE, we estimated the fraction of anthropogenic Ce in the sludges based on individual Ce/REE ratios. For the individual sludges the anthropogenic contributions were very variable (10–100%) but consistent fractions were obtained for individual sludges when calculated based on Ce/Dy (dysprosium), Ce/Er (erbium) and Ce/Eu (europium) ratios. Electron microscopy analysis of sludges dominated by anthropogenic Ce revealed that the Ce was mostly contained in nanoscale particles devoid of elements characteristic of Ce-bearing minerals. Thus, anthropogenic Ce contents derived from REE patterns may be used to validate ...

Quantification of individual Rare Earth Elements from industrial sources in sewage sludge

Authors: Kaegi, R.; Advisor: -; Participants: Gogos, A.; Voegelin, A.; Hug, S.J.; Winkel, L.H.E.; Buser, A.M.; Berg, M. (2021)

Rare Earth Elements (REEs) are used in increasing amounts in technical applications and consumer products. However, to date, the contribution of industrial sources to the loads of individual REEs in wastewater streams have not been quantified. Here, we determine the REE contents in sludge collected from 63 wastewater treatment plants (WWTPs) across Switzerland. To quantify the industrial fraction of individual REEs in the sewage sludge, we develop two complementary approaches, based on REE ratios and REE pattern fitting. Unspecific (background) inputs, with REE patterns similar to the averaged REE pattern of soils collected across Switzerland, dominate the REE budget of most WWTPs.