year in review 2018 Paperturn - Page 149



2018: A YEAR IN REVIEW | RESEARCH
brick shapes and tensile strengths
to produce an innovative building
material. The development is also
good news for the environment and
global warming as bio-bricks are
made in moulds at room temperature.
(Regular bricks are kiln-fired at
temperatures around 1 400°C and
produce vast quantities of carbon
dioxide.)
“The longer you allow the little
bacteria to make the cement, the
stronger the product is going to be.
We can optimise that process,” said
Randall.
ingredient in fertilisers that underpin
commercial farming worldwide. This
is significant because the world’s
natural phosphate reserves are
running dry.
ZERO WASTE
FOUNDATIONAL WORK
The fertilisers are produced as part
of the phased process used to
produce the bio-bricks.
First, urine is collected in novel
fertiliser-producing urinals and
used to make a solid fertiliser.
The remaining liquid is then used
in the biological process to grow
the bio-bricks.
“But in that process, we’re only
after two components: carbonate
ions and the calcium. What we do last
is take the remaining liquid product
from the bio-brick process and make
a second fertiliser,” he explained.
The overall scheme would
effectively result in zero waste, with
the urine completely converted into
three useful products.
“No one’s looked at it in terms of
that entire cycle and the potential to
recover multiple valuable products.
The next question is how to do that
in an optimised way so that profit
can be created from urine.”
The concept of using urea to grow
bricks was tested in the United States
some years back using synthetic
solutions, but Lambert’s brick uses
real human urine for the first time,
with significant consequences for
waste recycling and upcycling. Her
work builds on foundational research
by Jules Henze, a Swiss student who
spent four months working with
Randall on this concept in 2017.
“It’s what I love about research.
You build on the foundations of other
work,” said Randall.
Chemically speaking, urine is
liquid gold, according to Randall. It
accounts for less than 1% of domestic
waste water (by volume) but
contains 80% of the nitrogen, 56%
of the phosphorus and 63% of the
potassium of this waste water.
Some 97% of the phosphorus
present in the urine can be converted
into calcium phosphate, the key
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