Construction resources and aggregates company Lafarge Ash Resources aims to have fly ash exempted from the National Waste Management Amendment Bill’s classification as hazardous waste.

This exemption will improve the sustainability of construction materials and improve the cost effectiveness of construction projects, says Lafarge Ash Resources MD Tshepiso Dumasi.

The company has been processing fly ash into cementitious building materials for the local cement and concrete industries for 30 years, with local demand for processed fly ash products exceeding two-million tons a year. “It, therefore, cannot be classified as waste, he says.

“Fly ash is virtually zero-carbon-rated and its development has an important ‘green engineering’ role, owing to lower process and energy input, carbon dioxide (CO₂) emissions and the consumption of nonrenewable natural resources.”

He adds that the use of Ash Resources’ products by the local cement, readymix and construction industries during the past ten years has saved more than 17.5-million tons in greenhouse-gas emissions.

However, coal-fired power stations continue to dispose of a significant amount of ash material at landfill sites, which would logically be classified as waste. The problem of classifying a material as waste is one of the issues complicating the drafting of waste management regulations.

“The role fly ash plays in South Africa’s development can be accelerated if processed fly ash is exempted as a hazardous waste. The exemption would lead to avenues of ash use in other sectors, which will require more labour to develop, thereby reducing unemployment,” Dumasi avers.

The trace element content of South African fly ash differs from that in the northern hemisphere and the concentrations of many toxic elements, such as arsenic, of South African fly ash are much lower than those of their counterparts elsewhere in the world, says South African Coal Ash Association president Professor Richard Kruger.

Meanwhile, normal handling precautions for a powdery material, such as fly ash, need to be taken, such as wearing goggles. Exposure to the eyes and skin should be minimised because fly ash is an alkali and can cause irritation.

Health and safety testing indicates that fly ash can be harmful to aquatic life, but environmental best practice dictates that materials of any sort should not be dumped in rivers or lakes, Kruger adds.

The National Waste Management Amendment Bill makes provision in Section 74 for the Minister to exempt or exclude any waste stream or portion of a waste stream from the definition of waste.