360º PERSPECTIVES | ISSUE 7 | 2020/2021
45
No flash in the pan
S
OME NUMBERS AND DIMENSIONS ARE EASIER TO UNDERSTAND THAN OTHERS, like the
height of a person, the distance from Cape Town to Durban, even a country’s GDP. But those involved with fly ash and zeolites are a little mindboggling at both ends of the spectrum. Consider this. Eskom generates 90% of its electricity through coal-fired power stations, with the balance produced by hydro-electric and nuclear facilities. Together, they consume about 90 million tons of coal and 320 Ml litres of water (1,5% of South Africa’s total water consumption) per annum and spew 42% of the country’s greenhouse gases into the air. Because most of the coal used by Eskom is low quality with a high ash content of 40%, burning it produces 36 million tons of fly ash waste annually, the equivalent, as UWC’s
Professor Leslie Petrik likes to imagine it, of at least six dumps the size of the 146 metre-high Great Pyramid of Giza. Fly ash is the main component of the coal ash produced by incineration in the power station boilers and it’s pretty horrible stuff, consisting of very fine particles of unburnt carbon, boron, selenium, cobalt, chromium, molybdenum and vanadium; oxides of silicon, aluminium, iron, calcium, magnesium, potassium, titanium and sulphur; toxic elements such as mercury, arsenic and thallium; as well as soluble salts. Whether the dumps are irrigated or dry, rain and chemical >>
» Fly ash is the main component of the coal ash produced by incineration in the power station boilers. «