Professor grows bricks from bacteria

Ginger Dosier has invented a revolutionary new building material - a brick made of nothing but sand, bacteria and urine.

Prof Ginger Dosier shows a brick made of sand, bacteria and urea in her laboratory at American University of Sharjah.

SHARJAH // As she moved across the US for what was to be the last time, Ginger Dosier was tired of throwing away her furniture. She started looking for a way to cut down on her waste. Instead, she wound up inventing a revolutionary new building material - a brick made of nothing but sand, bacteria and urine.

Now construction experts say the unconventional building blocks could make a huge dent in the environmental impact - and cost - of building. Professor Dosier, now teaching architecture at the American University of Sharjah, took her first stab at waste reduction with furniture made of salt. "I wanted to make something that would go away. So that really started the chemistry and the science aspect."

From there, a brick made from organic materials seemed like a next logical step. "I decided I didn't want things to die or go away," she said. "I wanted them to stay around. "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. Concrete production requires high amount of heat, so I started to look at growing architectural materials. It transpired into if we could grow architectural materials with micro-organisms because they are a fuel source. I also studied coral growth because it is very similar in the sense that here is calcium carbonate production."

With some local sand, bacteria, and urea - made from processed urine - as well as a bottle and a cast, the bricks take between four and seven days to come into being. "You do need urea and of course you need water and calcium chloride. The urea can either be produced synthetically or come from waste." First, the dry sand is put into a mould. The urea is mixed into a solution with a lab-cultured bacteria, and poured into the sand.

And then you wait for up to a week. During this time, the bacteria feed on the urea, making calcium carbonate - an ingredient of cement - as a byproduct. "It's synthetic sandstone," she said. "All that's happening is crystals are growing around sand grains." Those crystals, she says, are completely insoluble. "It should technically last as long as sandstone." Prof Dosier says she is about five weeks away from working her way up to a standard-sized brick. So far, the bricks produced have been about 3cm long, 1.5cm wide and a centimetre deep.

The big advantage of this process is that unlike conventional bricks, which have to be fired at high temperatures, it uses very little energy. "You look at the materials we use in construction and pretty much all of them use some form of fuel source whether it's some form of transportation of bricks or concrete, which still requires high amounts of heat." Once they have full-size bricks, the next step is to build a wall. Prof Dosier plans to use mortar made in much the same way, but without the urea.

"I've talked to a few of my students who have ties with the bedouin community and talked about going out there and building with it with people. I can do the full-scale test and lay a few [bricks] but for me the joy will be going out there, taking the equation and the process, and actually staging it through." Local construction experts said they would welcome a chance to reduce costs. Ibrahim Khan, technical manager of SS Lootah Ready Mix, one of Dubai's biggest concrete suppliers, said the process could be a boon to the industry.

"Concrete takes up a lot of energy and this would help the environment," he said. "This latest development would take a lot of harmful chemicals out of the process which cause a lot of pollution." Mario Seneviratne, a sustainability engineer who is the director of Dubai-based Green Technologies, said the bricks could play into the increasing demand for energy efficient building materials. "You can't stop innovation and people from doing these things," he said. "It is good that people are coming up with these type of things."

He added that if Prof Dosier's low-energy bricks helped cut down on the use of cement, they would benefit the environment. "Cement is one of the biggest consumers of energy. It is a very carbon-intensive process and takes up about six per cent of the world's energy. Any substitute to that with the same properties with a smaller footprint is welcomed." Prof Dosier doubts that her bricks will get such a warm reception from the brick industry.

"If anything that would be the industry that would want it squelched. To be honest, it is replacing Portland [cement, which is used to make concrete]." She remains optimistic. "For me the sky is the limit. This could be larger precast pieces or could be used in foundations. There are endless amounts of possibilities in terms of the construction industry." [e-mail]