Human Waste

Australia: Researchers develop method to convert urine into fertiliser

A research team at the University of Melbourne developed a way to convert human urine into fertiliser.

A research team at the University of Melbourne developed a way to convert human urine into fertiliser.

Making use of electro-bioreactors, a membrane-based technology used to treat wastewater, the scientists extracted nitrogen and phosphorus from urine to create fertiliser.

As the method makes use of electrochemical processes, unwanted substances such as antibiotics, drugs, viruses and diseases are bound to break down in the reactor or set to flow out with waste urine post extraction.

Dr. Stefano Freguia, chemical engineering researcher and team lead, is confident about the technology’s various applications.

“The idea is to create a circular economy of nutrients in Australia by re-using human urine as a source of fertiliser that could initially feed the growth of urban farming like hydroponics, but also ultimately supply broadacre agriculture.”

According to him, the bioreactors used within the research remit do not only serve to effectively filter nutrients such as nitrogen and phosphorus from treated urine but also help save money as the electricity needed for said electrolysis is sourced from chemical energy contained within the urine itself.

The Australian Research Council Hub for Nutrients in a Circular Economy (ARC NiCE Hub) will test the urine processing technology at a public park in Brisbane. The pilot project will see the urine sourced from 300 people converted into fertiliser per day.

A previous test conducted under lab conditions generated 10 litres of fertiliser for 100 litres of urine.

Human waste only accounts for 1% of sewage flow in Australia but contains 80% of waste nitrogen and 50% of waste phosphorus to be found in the country’s sewage system. As such, cities like Melbourne or Sydney could supply around 25% of necessary fertiliser needed for food production if human waste would be seen as a resource.

Yet, due to the commonly attributed ‘ick factor’ that has come to characterize human waste in the general mindset, investment and research in technologies utilising excreta for energy as well as for agricultural purposes has been relatively scarce.

Dr. Ferguia intends to change this in the near future by crafting an information campaign to inform and encourage the public to take a more positive stance on the issue.

A shift in attitude appears doubly important, considering the challenges of producing commercial fertilisers. The production process for nitrogen fertiliser is highly energy intensive whilst phosphorus has been classified as a critical resource bound to run out in less than 100 years.