M-LS by O.C.O Technology: a carbon-negative limestone aggregate created with residues from waste to energy residue
When waste to energy plants process non-recyclable waste to generate energy, they create a by-product called air pollution control residue (APCr) – a hazardous waste in the form of solid ash. O.C.O Technology has pioneered Accelerated Carbonation Technology (ACT), to recycle this residue into M-LS - the World's first carbon-negative aggregate for construction.
The process involves:
- Blending APCr and other wastes to form a reactive mixture
- Stabilising the reactive mixture with liquid CO2 and water
- Combining the stabilised mixture with binders and fillers
- Pelletising the combination
- Curing the pelletised combination to create the M-LS.
The UN's 6th Global Environmental Outlook for the pan-European region recognises the O.C.O Technology, stating that such "aggregates, which have a structure similar to natural limestone, meet European ‘end of waste’ regulations and materials performance standards, and make a demonstrable contribution to the developing European circular economy." For more information, view O.C.O Technology's website here.
The construction industry uses this aggregate to produce masonry units, precast concrete, ready-mix concrete, screed, and other products.
Every tonne of this material saves 1.4 tonnes of non-replaceable natural aggregate. The carbon-negative aggregate captures more CO2 than is emitted during its manufacture. Every one thousand tonnes of M-LS permanently captures the same amount of carbon dioxide as 4000 trees in a year.
O.C.O Technology has developed a network of UK facilities to recycle 150,000 tonnes of APCr each year, with factories in Avonmouth, Leeds and Suffolk.