Local engineer turns urine into fertiliser

November 15, 2021

She has hopes that it may even be used to make jet fuel one day.

Hlumelo Marepula is a Masters candidate in the Faculty of Engineering at the University of Cape Town and she has devised a brilliant method that turns urine into fertiliser as part of her studies.

Most people would rightly view urine as a product of waste, meaning it has little to no value. But Hlumelo decided to explore the possibility of using urine to create one of the most essential commodities used by farmers around the country to grow crops.

As a result of her efforts, she recently won an award for creating an urea-ethanol solution that is recrystallised to make fertiliser or urea. Her invention is so powerful that it might even be used to one day create jet fuel from urine.

Hlumelo has been working closely with her supervisor, associate professor Dyllon Randall from UCT’s department of civil engineering, to develop her method, which clearly proves to be feasible.

She has explained that urine can be used to create fertiliser due to its high urea contents. Urea is a raw material in producing various chemicals and is also a critical nitrogen-rich fertiliser.

“… Especially in a continent like Africa where we have so much arable land and the synthetic version of urea, the one that’s made in factories, uses a very energy-intensive process which is quite harmful and contributes a lot to climate change issues,” she said.

Several waterless urinals were installed on the UCT campus and students were invited to donate their urine for this project. The urine from the urinals were taken to a lab and processed there by Hlumelo and her team.

“The vision is to try and retrofit sanitation in existing buildings so that the urine is no longer going to sewage waste streams and being taken to water treatment plants and have, for example, a separate piping system that diverts all the urine to a central system,” she said in an interview with Business Insider.