Scientists from Australia have unveiled a toilet design that uses technology to separate the nutrients in urine that are good for reuse while removing unwanted chemicals, including heavy metals.
In a paper, the team said urine contains all key macronutrients such as potassium, phosphorus and nitrogen needed for plant growth and is, therefore, an “excellent fertiliser”.
However, they suggest that direct reuse is not recommended due to the presence of heavy metals in urine.
The researchers believe their novel system would remove the need for mining and would be a sustainable solution for farming.
Currently, the phosphorus needed for fertilisers is produced from minerals locked in phosphate rock mines of which there are limited stocks.
Their application aims to recover nutrients from waste streams and recycle them for fertiliser production.
The toilet powers itself and uses an anode and cathode, components found in typical batteries, to separate chemicals in urine.
Surrounding air will be used as a catalyst for this process.
The system is expected to roll out in Australian parks soon.
Cara Beal, Associate Professor from Cities Research Institute at Griffith University in Queensland, described human urine as a “treasure trove of nutrients”.
Ms Beal said: “It’s a concentrated supply of all the nitrogen, phosphorus and potassium needed for plant growth and is surprisingly clean compared to other waste.
“Current methods to create fertiliser pull nitrogen out of the atmosphere in an energy intensive process with a massive carbon footprint. As a society, if we are to get to net zero carbon emissions we are going to have to move away from synthetic fertilisers.”