Separate collection of urine and production of urine-derived fertilizers can increase resource efficiency at the food-energy-water (FEW) nexus. Recovering nutrients from concentrated wastewater streams such as urine to produce fertilizers for food systems can increase life-cycle energy efficiency. By obviating two energy-intensive processes, biological nitrogen removal and Haber-Bosch fertilizer production, creating nitrogen fertilizers from urine improves receiving water quality at lower energy demands than conventional management. A key barrier to large-scale production and application of urine-derived fertilizers is identifying risks associated with pharmaceuticals, particularly because 65% of excreted pharmaceuticals are found in urine. Pharmaceuticals in fertilizers can potentially affect soil quality by application, public health through consumed crops, and aquatic ecosystems through runoff. Previous research has identified several pharmaceutical compounds present at high concentrations and widely distributed in urine. Thus far, most studies on pharmaceutical removal during urine treatment have employed target analysis to evaluate removal efficiencies of parent compounds. In our target screening of 13 pharmaceuticals in urine applied to lettuce and carrots, low levels were measured in plant tissue (&lt; 200 ng/g) and runoff water (&lt; 600 ng/L). Spiking pharmaceuticals known to be excreted in wastewater into urine and measuring them during urine treatment helps quantify risks associated with parent compounds in urine-derived fertilizers. However, non-target analysis is needed to more broadly identify potential toxins introduced during the production of urine-derived fertilizers. In this study, we applied non-target analysis and suspect screening using a database of endogenous and exogenous metabolites to characterize pharmaceutical fate during urine treatment. High-resolution mass spectra from samples throughout a urine treatment train (acidification, reverse osmosis, and distillation) were compared to identify unknown compounds by non-target analysis. Results from this study can be paired with bioassays and effects-driven analysis to prioritize compounds to monitor as indicators of toxicity in crops and waterways associated with urine-derived fertilizers. This study is part of a larger body of work aimed at advancing energy-efficient technologies that efficiently process urine into safe, effective fertilizers for food production.

Assessing risks from pharmaceuticals and transformation products in urine-derived fertilizers

255th National Meeting (2018)

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