Monitoring the Removal Efficiency of Pharmaceuticals and Hormones in Different Treatment Processes of Source-Separated Urine with Bioassays

Urine can be collected separately from the general wastewater with the aim of recycling the nutrients. Urine source-separation not only prevents wasting nutrients but also prevents potentially hazardous micropollutants from entering the wastewater stream and tainting a final fertilizer product. We assessed various urine treatment technologies for their performance to remove micropollutants such as pharmaceuticals, natural and synthetic steroid hormones, and their human biotransformation products. Removal efficiencies were determined with a combination of bioassays and chemical target analysis. The yeast estrogen screen yielded information on estrogenicity. Specific phytotoxicity and nonspecific baseline toxicity was determined with an algae chlorophyll fluorescence test. Filtration methods, such as nanofiltration and electrodialysis, were highly efficient with respect to toxicity reduction. Micropollutant degradation during biological treatment in a sequencing batch reactor was very compound specific. Ozonation removed the target analytes and the estrogenicity completely, but the baseline toxicity was only reduced by 50−60% depending on the ozone doses. Struvite precipitation produced a very “clean” fertilizer product that is ready to use. The examples show that bioassays and chemical analysis yield complementary information, but are very useful to monitor treatment efficiencies and to assess the ecotoxicological potential of byproducts of urine treatment processes. The results of this study present a method to assess the micropollutant removal efficiency, and therefore, support the choice of an appropriate urine processing technique for real-world applications.