Aerobic and anaerobic formation and biodegradation of guanyl urea and other transformation products of metformin

The aim of the study was to investigate the biodegradability of guanyl urea (GU) and the behavior of other transformation products (TPs) of Metformin (MF). Most biodegradation studies of MF with activated sludge of waste water treatment plants (WWTPs) showed GU as the only bacterial dead-end metabol...

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Bibliographic Details
Published in:	Water research (Oxford) 2019-02, Vol.149, p.130-135
Main Authors:	Tisler, Selina, Zwiener, Christian
Format:	Article
Language:	eng
Subjects:	Antidiabetic Biodegradation Guanyl urea Metformin Transformation products Waste water treatment
Online Access:	Get full text
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Summary:	The aim of the study was to investigate the biodegradability of guanyl urea (GU) and the behavior of other transformation products (TPs) of Metformin (MF). Most biodegradation studies of MF with activated sludge of waste water treatment plants (WWTPs) showed GU as the only bacterial dead-end metabolite without further degradation. In this study, batch experiments with activated sludge revealed biodegradability of GU. GU degradation was much faster under anaerobic than under aerobic conditions. Degradation kinetics for MF was much slower under anaerobic conditions. Adsorptive removal of up to 20% was an additional elimination process of MF and GU. The batch experiments were conducted with sludge of 2 WWTPs, WWTP 1 showed decreasing concentrations of GU from influent to effluent and the other increasing concentrations. This indicates a different adaption of the sludge to GU and may explain the better GU degradation capability of the sludge from WWTP 1. Furthermore, the biodegradation potential of MF was confirmed and in addition, occurrence of the TPs methylbiguanide (MBG), 2-amino-4-methylamino-1,3,5-triazine (2,4-AMT) and the secondary TP 2,4-diamino-1,3,5-triazine (2,4-DAT) was observed in batch experiments with activated sludge of WWTP 1. After fast formation, degradation in turn was slower, especially for 2,4-AMT. In general, TPs played a minor role in MF and GU degradation. [Display omitted] •Guanyl urea revealed as biodegradable under anaerobic and aerobic conditions.•Degradation capability of guanyl urea in lab experiments is also reflected in full-scale plants.•Other transformation products of metformin were formed below 2%.
ISSN:	0043-1354 1879-2448