The sanitation and urban agriculture nexus: urine collection and application as fertilizer in São Paulo, Brazil

Urban Farm DB summary

Separately collected urine is presented as an attractive potential fertilizer because of its high nutrient content, low cost, and inherent link between urban wastewater management and peri-urban agriculture. Urine from waterless urinals was applied to corn and lettuce to examine the impact of application rate and frequency on plant growth and soil parameters; in both crops, urine application significantly (p < 0.05) increased growth and leaf production relative to control plants. More frequent applications led to lower soil cation exchange capacity for corn and higher soil nitrogen content for both crops. Preliminary implementation calculations suggest that installing waterless urinals at the University of São Paulo's School of Arts, Sciences, and Humanities campus could save over 1,500 m³ of water and produce 360 m³ of urine annually; these experimental and modeling results are discussed in the context of scaling up urban urine collection, transport, and fertilization in São Paulo, Brazil.