This handmade kit creates a personal experience of participating in a productive food cycle. Human urine, the natural product of our bodies’ daily metabolism, is a sterile solution rich in excess nutrients. The kit lets you recycle the excess nutrients your body creates when you eat and drink into more life, locally. You can take this kit home, pee in it, and perform a biochemical reaction that transforms the nutrients in your urine into an immediately usable fertilizer to feed your own plants.
For more information about using the kits, see the Your Pee page.
About the chemical process:
You will be prompting ocean-derived magnesium to bond with the nitrogen, phosphorus, pharmacological micropollutants, and other metabolites in your urine. As a result, you will produce a solid fertilizer called struvite and a liquid by-product. You can use the struvite solid as a fertilizer for your houseplants. Its nitrogen and phosphorus content will nourish them and promote root growth. The liquid by-product of the reaction is less likely than your raw urine to create conditions of eutrophication and pharmacological micropollution in the waterways beyond your toilet.
Urine is an aqueous solution of unused electrolytes and metabolites our kidneys produce to maintain homeostasis within our bodies. Every batch of pee is different, but on average, human urine consists of 59% urea.
Urea is an organic compound with the formula (NH2)2CO.
The nitrogen in urea cannot bond with magnesium until hydrolysis frees it from the urea in the form of ammonia. Hydrolysis occurs automatically in nature and in sewage pipes over longer periods of time when sterile urea meets environmental bacteria. You will be accelerating this process by adding an enzyme, a concentrated urease derived from jack beans.
Urease catalyzes the hydrolysis of urea into released carbon dioxide gas and liquid ammonia:
(NH2)2CO + H2O → CO2 + 2NH3.
The magnesium chloride (MgCl2) bonds with the nitrogen in ammonia and the phosphorus in the urine to create struvite. Researchers have found that this chemical process is also highly effective in removing some pharmacological micropollutants from the remaining liquid by-product that you will be flushing down the toilet.
Struvite, or ammonium magnesium phosphate, (NH4)MgPO4·6(H2O) has been used as a fertilizer for centuries. The small amount left in the glass bowl will nourish your new watercress seeds as they germinate and allow them to grow hydroponically until maturity.