‘Scientists look at using bacteria to repair and even build large scale structures’
This includes the obvious, such as roads, railways and skyscrapers, but also the things you don’t see but can’t live without, such as your water supply networks, sewers and building foundations.
Most of what we build uses a lot of steel and concrete as well as involving the ground itself. Despite being everyday sights, these are incredible materials and contribute to our ability to build incredible structures, but they’re not infallible.
Biology and civil engineering haven’t had much to do with each other in the past, although my background is in one such overlap – the area of bioremediation, where microorganisms are used to clean up pollution.
I got into it after working in the oil industry and, feeling guilty about it, I switched jobs to help clean up some of the mess I’d made. I’m now working on using living things, particularly microscopic things like bacteria, to create structures both as a replacement of, and in combination with, these familiar building materials.
The basis of this is that bacteria, despite being tiny, can be present in the environment in huge numbers (you can get more than 100 billion of them in a handful of soil) and can have a big effect when they work together.
They produce materials that can cement soil particles together, effectively turning it into rock, and even heal cracks in concrete.
Scientists in the Netherlands have even developed a process where as soon as concrete cracks – as it always will – bacteria embedded within it immediately go to work to heal the crack.
The processes involved are often quite simple, and are based on feeding bacteria so they grow and produce the cement.
Applying these to real world environments and getting bacteria to survive and perform their tasks in the right place and at the right time is where the difficulty arises.
Our work particularly focuses on soil and how this treatment will affect its ability to sustain the pressures applied to it by structures and the environment.
Although this is still mostly being explored in the laboratory, its potential is beginning to be explored by the civil engineering industry.
So why do it? There are plenty of technical reasons.
The production of both concrete and steel takes a lot of energy and raw materials, with all sorts of environmental impacts – concrete production is one of the biggest single emitters of CO2, for example.
If we can replace these with biological products we can reduce the energy and material consumption and cost of construction.
Also, this technology could be applied in all sorts of areas where current engineering methods are difficult or expensive to apply, such as strengthening large areas of slopes to prevent landslides or strengthening the foundations of existing buildings. They could even be used in coastal defence by helping to prevent erosion of the seabed.
What is essentially sticking sand together with biological glue could be the next big thing in producing the world you see around you.
To contact Michael please email HarbottleM@cf.ac.uk.
This article first appeared in the Western Mail‘s Health Wales supplement on the 31st October 2011, as part of the Welsh Crucible series of research profiles.