Probing the degradation of pharmaceuticals in urine using MFC and studying their removal efficiency by UPLC-MS/MS

Nutrient recovery from source-separated human urine has attracted interest as it is rich in nitrogen and phosphorus that can be utilized as fertilizer. However, urine also contains pharmaceuticals, steroid hormones, etc. and their removal is crucial as they have detrimental effects on the environment and human health. The current study focuses on investigating the degradation of pharmaceuticals using a double-chamber microbial fuel cell (MFC). Urine was spiked with four pharmaceuticals (trimethoprim, lamivudine, levofloxacin, and estrone) at a concentration of 2 μg/mL. The MFC was operated for 7 months in batch mode with this spiked urine as feed. The degradation efficiency of the MFC was studied, for which a selective liquid chromatography-tandem mass-spectrometric method was developed for the quantitation of compounds used in the spiking experiments and was validated with a lower limit of quantification of 0.39 ng/mL. The maximum removal rate achieved was 96% ± 2%. The degradation mechanism involved processes like sorption and anoxic biodegradation. The voltage curve obtained showed that the presence of pharmaceuticals had an initial negative impact on power generation along with increased organic content; however, after the reactor acclimatization, increased power output was achieved with maximum organics removal at 30 h of retention time. This work opens a new perspective for the anoxic biodegradation of pharmaceuticals and can be useful in future bioremediation studies.