Liquid gold has been discovered at the University of Cape Town.
It comes in the form of urine‚ which engineering students have transformed into fertiliser and bricks.
Now UCT says urine from its urinals has the potential to produce six tons of fertiliser a year — twice the amount it uses on its sports fields.
Said civil engineering lecturer Dyllon Randall: “Chemically speaking‚ urine is liquid gold. It makes up less than 1% of domestic wastewater but contains 80% of the nitrogen‚ 56% of the phosphorus and 63% of the potassium of this wastewater.
“We literally pee away these valuable nutrients every day.”
After spending two years in Switzerland working on a “reinvent the toilet” challenge funded by the Bill and Melinda Gates Foundation‚ Randall challenged four civil engineering doctoral students to continue his work‚ which was aimed at making toilets self-sufficient.
Craig Flanagan built a urinal containing calcium hydroxide‚ which reacted with urine to produce calcium phosphate. Phosphate is a key ingredient in fertilisers‚ but natural deposits of phosphate are expected to expire within the next 50 years.
Student Suzanne Lambert took Flanagan’s leftover urine and put it into sand that had been colonised with an enzyme that produces calcium carbonate. Randall said this cemented the sand into any shape — such as a brick — and was the first time this had been done with urine.
“The bio-solids typically have the same compressibility strength as conventional 40% limestone bricks‚” said Randall. “The next step will be to make an actual brick using this process.”
By-products of the bio-brick process are nitrogen and potassium‚ which are also used in fertilisers.
Bilaal Kowdur harvested 110 litres of urine from 10 makeshift urinals installed at a UCT residence and used it to make nearly 2kg of fertiliser. He also found that students were happy to use such a device in future.
Finally‚ Tinashe Chipako researched the feasibility of installing waterless urinals on upper campus and found that UCT uses the equivalent of about seven Olympic-sized swimming pools of water annually just to flush urinals.
Flanagan won a R30‚000 Greenovate Award for environmental achievement last week.
By: Dave Chambers
Source: TMG Digital.