Australia currently generates around 70% of its power from coal and it is a little known fact that the by-product of the coal burning process is ash.
Why is this interesting? Well, fly ash and bottom ash could arguably be the single largest homogeneous waste stream in Australian at around 13 million tonnes per year (half a tonne for every man, woman and child) but it is poorly recycled by global standards due to over-control of the industry by large cement companies.
The ash expended by power stations is toxic as it contains heavy metals and other materials which can (and do) have adverse impacts on the health of neighbouring communities and the environment.
Ash is removed from the power plant by way of a sludge that is pumped out to the ash dam where it sits uncontained by dam liners or covers. The ash then blows off site as dust, leaks through to groundwater and is often flushed out over dam walls with heavy rainfall events.
The ash itself has been identified by Australian circular economy entrepreneurs such as Nu-Rock who use the ash to make a cheaper masonry product such as bricks, which are actually superior in strength. Their ability to grow their market and use of their recycled products, (avoiding energy intensive cement production also) has been hampered by the larger cement companies. For example, in 2017, Cement Australia was fined $20 million for restricting fly ash supply.
In other countries, recycling of coal ash is up to 97% (Japan), UK (70%), China (69%) and India (61%), with an average of 53%. With Australia’s power stations only having 43% removed from the ash dams, we have significant room for potential, especially given the economic and environmental sense use of recycled ash would make.
Perhaps more so than any other waste product in Australia, coal ash requires government intervention to ensure it is recycled. This is the lowest hanging fruit in the waste industry.
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