Extracting fertilizer from human urine - Hlumelo Marepula
Channel: Future Water Institute, University of Cape Town
Date: 2021-09-16

The African continent has the largest area of arable land with the Sub-Saharan region accounting for 20% of the global agricultural land by area. However, fertilizer use for food production in Africa remains very low because synthetic fertilizers are often expensive for most small-scale farmers.  This has an impact on food security and calls for affordable and sustainable methods for producing fertilizer. 

Urea is the most frequently used fertilizer by farmers globally. The conventional process to manufacture synthetic urea operates at high temperatures and pressures and is, therefore, energy-intensive. The aim of this work was to investigate the feasibility of recovering urea crystals from human urine using a novel ethanol evaporation and recrystallization process that exploits the solubility differences of urea and impurities in water and ethanol. This approach could provide an accessible method to produce urea that operates at atmospheric pressure and temperatures lower than 30°C. 

In this research, science, technology, and innovation are used to address food insecurity and the lack of sanitation in Africa. A novel fertilizer-producing urinal is used to collect urine and our process converts the urine into multiple fertilizers, thus also providing food security. 

References: 
Marepula, H., Courtney, C.E., Randall, D.G. 2021. Urea recovery from stabilized urine using a novel ethanol evaporation and recrystallization process, Chemical Engineering Journal Advances, 8, 100174.