Sand+bacteria+urine= bricks: continuing performances of bacillus pasteurii

 

“It’s synthetic sandstone. All that’s happening is crystals are growing around sand grains.”

The way in which Professor Ginger Dosier describes her innovative process that has recently won the Metropolis “Next Generation” design competition is accurate, but perhaps slightly over-simplified.

I never ceased to be amazed by friendly bacteria. We may have an instinctively negative view of our super-abundant microbial colleagues, but many of them are really helpful, and we’d be in a bad way without them. Take, for example, the bacteria that munch on natural crude oil in ocean water or in sand; take the wondrous critter, bacillus pasteurii, that can turn sand into sandstone and heal cracks in concrete. And now here, although appearing under a different name, is bacillus pasteurii again.

Ginger Dosier is an architect at the American University of Sharjah, in the United Arab Emirates, but an architect with a difference: she is interested in designing her own building materials and thereby participating directly in influencing the performance of a building. She has chosen the most basic of building materials, the brick; as she comments,  “Bricks are so humble, they are the lowest common denominator in architecture. Bricks were designed around our hands; one is used for holding the brick and the other for the trowel. I wanted something that would slip right into the system and the entire construction system would not have to be redefined.” And what she has done is potentially of huge importance, because bricks may be humble, but their manufacture consumes large amounts of energy and creates more atmospheric pollution than the entire aviation industry. A standard brick must be fired in a kiln at temperatures greater than 1000 degrees centigrade; making a couple of bricks generates more than a kilogram of carbon dioxide – and it’s estimated that perhaps 1.2 trillion bricks are manufactured around the world every year. Dosier’s solution is don’t bake the brick, grow it.

And this is where our old friend, bacillus pasteurii plays the leading role. Although the reports of the brick-making process describe the bacteria used as sporosarcina pasteurii, it would seem that this is just an alternative (stage?) name for bacillus pasteurii  - why the microbiologists can’t make up their minds is beyond me, but there we are.  Bacillus pasteurii, if treated right, produces calcite that can glue sand grains together (or mend concrete, for that matter); the process is referred to as microbial-induced calcite precipitation, or MICP. Treating the bacteria right requires feeding them which is where the urine comes in – urea [(NH₂)₂CO] can be made synthetically or from urine, and provides nutrition for the bacteria. Water is also necessary, as is calcium chloride.

The process for making a brick is relatively straightforward: put dry sand into a mould, add the cultured bacteria, water, urea, and calcium chloride, and wait for about a week – other than the 37 degrees centigrade at which the bacteria must be prepared, no heating is required. But it took Dosier two years to find the right proportions of materials, the right microbes, and the right chemistry, and her eventual success was another example of laboratory serendipity:

Then one afternoon, she threw together a bunch of scraps from some old, ill-fated tests, for kicks. Practically forgetting about it, she revisited experiment No. 112 a week later, only to discover that the medium had transformed into a “baby brick,” as she tells it, a four-by-two-by-one-centimeter proof of concept. “I was shocked to find that it had worked,” she says, “and glad that I took detailed lab notes.” The magic formula was in allowing the right concentration of bacteria to fester just long enough.

Currently, her bricks are small - about 3cm long, 1.5cm wide and a centimetre deep – but she’s working on scaling up. And scaling up to any kind of commercial mass production process is yet another, hardly trivial, step. But the potential is huge. Dosier contemplates the ability to program a brick’s exact composition and then “ fabricate it layer by layer on a 3-D printer. The technology poses countless design possibilities. Ball-shaped bricks: Why not?” (Metropolis).

But, as usual, it’s still not quite that simple:

Microbial-induced calcite precipitation spews tremendous amounts of ammonia, as scientists affiliated with Delft University of Technology, in the Netherlands, discovered recently when they tried the chemical process on contaminated sand and soil. “High ammonia concentrations result in environmental eutrophication and eventually, via microbial conversion to nitrate, the poisoning of groundwater,” the Delft researcher Henk Jonkers writes in an e-mail. If the bacteria continues to convert ammonia to nitrous oxide, he adds, it can produce a greenhouse gas 320 times more powerful than CO2.

Dosier is thinking about emissions capture in the manufacturing process, another complex and multi-disciplinary challenge, but she’s up for it: having come so far as an architect learning and working in different worlds, she deserves to succeed.

[See also PopSci, Inhabitat, and the UAE site, The National, for more information]

Comments

[Jules]

It is always fascinating to learn how the microbial world;in spite of the real moratl dangers some species may pose to other lifeforms;that something so beyond our everyday concerns and many times dis-regarded as mundane or ugly is actually the vital support system that has enabled life to evolve and persist on this planet and probably elsewhere in the universe.

As a fuel source(algae)and in other ways microbial species may turn out to be the integral components of a sustainable society. From my understanding of ecology, there is nothing truly irrelevant or "inferior" in nature and the smallest part of it can have enormous consequences for the whole system. It is sad that our species(some of us at least)has only recently realized these vital interconnections as we increasingly exterminate or absuse and misuse other species and the earth's support systems at our own peril.

[Neil Belford]

Last time I looked Ammonia was a valuable industrial feedstock. The Ammonia production might pay for the entire process, if not at least for the raw materials.

Approximately 83% (as of 2004) of ammonia is used as fertilizers either as its salts or as solutions. Consuming more than 1% of all man-made power, the production of ammonia is a significant component of the world energy budget. - more of this at Wikipedia http://en.wikipedia.org/wiki/Ammonia#Uses

[Neil Belford]

[A clarification of the previous comment]

Last time I looked Ammonia was a valuable industrial feedstock. The generated ammonia, liberated no doubt from the urea, could be used to directly produce more urea on site, to feed back in to the process.

Approximately 83% (as of 2004) of ammonia is used as fertilizers either as its salts or as solutions. Consuming more than 1% of all man-made power, the production of ammonia is a significant component of the world energy budget. - more of this at Wikipedia http://en.wikipedia.org/wiki/Ammonia#Uses

[Sandglass]

That's something I certainly didn't know, particularly the scale involved. This is clearly potentially very interesting: I wonder if there's a possibility of your passing this on to Dosier?

Thanks for the comment!

[Maggie]

I am curious what effect the contamination had on the process in the Delft research. And what happened to the contamination once solidified in the sand brick?

[Sandglass]

Maggie - I'm honestly not sure of the answers to your questions. Henk Jonkers at Delft is best-known for his work on healing of concrete by bacteria (see my post from last year, http://throughthesandglass.typepad.com/through_the_sandglass/2009/05/more-adventures-of-bacillus-pasteurii---mending-concrete.html, and http://civil.engr.siu.edu/cheval/CEE210/Lecture/Introduction%20Material/Jonkers%20et%20al%202010%20Ecol%20Eng.pdf.)

It would seem that he is also working on bacterial clean-up of contaminated materials, sand and soils, and that this is the origin of his comment (only cited as an e-mail communication) on the bricks project. I would assume that the nitrate remains in the brick and the ammonia is given off as a gas.

Sorry I can't help more!

Michael

[V Lewis]

Another concern.
A major source of calcium is calcium carbonate, which comes from
organisms that have sequestered C02 by way of carbonic acid formation (sea shells and a lot of microorganisms). An obvious way to get CaCl2 would be 2HCl+ CaC03= CaCl2 + H2O + CO2. Unfortunately this would release a lot of CO2 a known green house gas.
However, a lot of CaCl2 may already be made at the bottom of fracking wells which have
been boosted by injecting HCL to promote the above reaction and the CO2 contributes to
cracking pressures.

[Jackie Juan]

Does anyone know where one might be able to get some Bacillus Pasteurii?

[Sandglass]

I see it has now changed its name to Sporosarcina pasteurii!

Incredibly if you google either name plus "buy" there are places that have it available, presumably for bona fide research. What is your interest?

[Rajaa Tware]

i'm curious if the bacteria can solidify the beach sand as strongly as it does the desert's, i mean, since it's wetter, does it work?
can it be used to build on the beach?

[Sandglass]

Water is necessary to the process, so there's no reason it shouldn't work on beach sand.

[rafay bukhari]

from where i can get bacillus pastuerii

[Sandglass]

Sorry, I am not a biochemist - I really don't know!

[Stephen Butler]

Bit of a strange one...... I analyse fertilizer samples, and one of my customers has a bit of an issue. One of his products is a mixture of Urea, Calcium Chloride, and Molasses. One of his customers is a farmer who dilutes this fertilizer in a water bowser with water that he gets from a borehole. The trouble is, the farmer is getting issues with blocked spray filters caused by a precipitation of what appears to be Calcium Carbonate. Could the farmer inadvertently be carrying out this process in his water tank? Is this bacteria, or any that do the same job, likely to be found in rural Hertfordshire, UK?

[Sandglass]

Fascinating!

I know that Bacillus pasteureii (now, I see, renamed as Sporosarcina pasteurii) is found in a wide range of soils and aqueous environment all over the world, so I suspect that there's no reason it shouldn't be thriving in rural Hertfordshire. It seems quite possible that this is what's going on with your farmer's water (but remember that I am just a geologist....)