Monday 06 Jan 2014 @ 15:20
Innovate UK
Innovate UK
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Carbon8 invents the building blocks of the future
Fêted by government and showered with awards, the waste management company Carbon8 Systems can trace its beginnings to a dish of dangerous sludge gradually solidifying on a geologist's desk.
The geologist, an expert on hazardous waste, was Dr Colin Hills. He saw that carbon dioxide (CO2) in the atmosphere was reacting with the sludge to harden it, and he experimented to see whether the process could be speeded up by using more CO2.
It could, and the result is a business he founded with three others that initially turns one specific industrial waste into aggregates that can be recycled into concrete blocks.
Carbon8 Systems is at the cutting edge of the green industry. The company's patented Accelerated Carbonation Technology (ACT) makes waste materials less hazardous, which means they can be disposed of without having to pay to dump them in landfill.
ACT involves mixing CO2 gas with waste and an exact amount of water; the process can be used to manufacture aggregate products for the construction industry at the same time as capturing carbon from industrial processes.
Vital support from the Technology Strategy Board
‘It is such a simple thing, why hasn't anyone else done it?' asked Dr Paula Carey, Managing Director of Carbon8 Systems. ‘And the Technology Strategy Board gave us the vital support we needed to allow our discovery to see the light of day,' she added.‘It goes back to the nature of the construction industry. Carbonation has been regarded as a bad thing because it corrodes steel and gives a finite life to reinforced concrete. Now that view is beginning to change.
‘There are a range of wastes we can treat. The first group is naturally reactive ones such as the waste from air pollution control in municipal incinerators,' Paula continued.
‘Polluting chemicals are captured by injecting lime into the flue gas that is then collected in filter bags and disposed of in landfills or stored underground at facilities such as the Cheshire salt mines. We eliminate the need for storage or landfill, by treating the material so it becomes a product that can be reused in construction.
‘Similarly, Carbon8 Systems is working on treatments for waste from cement kilns or steel works. The CO2 for these processes can be captured from the plants themselves. Our model is using CO2 in a process that pays for itself,' explained Paula.
Another project at North Farm Landfill in Kent, in collaboration with the Technology Strategy Board, the Environment Agency and Kent County Council, involved demonstrating that gas from landfill sites can be used to process waste for use on the site.
Normally, landfill gas is flared off, but for the pilot projects it was burnt in a controlled fashion to maximise the amount of carbon dioxide in the flue gas. This flue gas was used to treat a variety of wastes to produce an aggregate, to help restore the landfill site.
Landfill solutions
North Farm Landfill is a closed site that is suffering from subsidence. The processed waste was to be used as part of a new capping layer to prevent chemicals leaching from the landfill.The second group of wastes that can be treated consists of hazardous types - sludge from water treatment plants and contaminated soils. These are not sufficiently reactive with CO2, but in this case a binder such as cement is added to the waste first before it is mixed with CO2.
Quarry fines – the dust from crushing rock or clays washed out from gravel – accounts for the third group. ‘The fines can be used in the other two processes, but the difficulty is in making the economics work as there aren't disposal costs to be saved, as there are with the other types of waste,' added Paula.
Click here for the full success story and further information.
