SHOWS: CAPE TOWN, SOUTH AFRICA (NOVEMBER 02, 2018) (REUTERS) – Going to the toilet to pee could result in building materials for a new home if South African researchers who made the world’s first bio-brick from “liquid gold” have their way, the brick’s pioneer said on Friday (November 2).
“The first stage of making the brick is collecting the urine and to do that we use calcium hydroxide to stabilize the urine to get it to a PH where the ammonia is not hydrolyzed, and then the urea is not hydrolyzed and then from that point we add calcium chloride so that we can increase the calcium concentration in our urine media that we gonna use to pump into the bricks and then from that point we pump that into the bricks with the sand and grey water mixture and those are all the ingredients to the brick,” said Vukheta Mukhari, a civil engineering student that is part of the team that developed the bio-brick.
The same process is used to produce fertilizers.
“If we consider for example the amount of waste water we produce from our homes, in terms of volume, urine only makes up one percent of that waste stream. But it contains over 80 percent of the nitrogen, about 70 percent potassium and 50 percent of the phosphorus. Now those are three key nutrients needed to make any organic fertilizer and literally we pee those away every single day and we flush it through our sewer networks. Why shouldn’t, why should we not be recovering it instead and basically making multiple products and in my mind, that’s the way we achieve a truly sustainable future,” said Dyllon Randall, a senior lecturer at the University of Cape Town’s civil engineering department who is part of the team that developed the brick.
The bricks are created through a natural process called microbial induced carbonate precipitation, similar to how coral reefs are formed.
To make a brick, loose sand is “colonized” with bacteria that produce the enzyme urease, which in turn breaks down the urea in urine while producing calcium carbonate through a complex chemical reaction.
One can make a brick of any shape using this process.
The bricks are formed at room temperature, cutting out huge amounts of harmful carbon dioxide produced when making regular bricks that are kiln-fired at temperatures of 1,400 degrees Celcius, Randall added.
“I definitely see commercialization in the next decade or two. There’s lots of optimizations, still a lot of lab work to be done, logistical issues obviously with collecting urine, creating the fertilizers, like there’s a lot of things that still to be ironed out before it can go out into the world,” added Suzanne Lambert, who is part of the development team.