Coal Ash Waste is the single largest waste stream in South Africa. In any single day, a large coal-fired power station can result in the generation of a substantial amount of Coal Combustion Products (CCPs) or coal ash waste.

In South Africa, it is common practice to dispose CCPs to both wet and dry ash disposal facilities. Looking at industry trends it appears that the development of Dry Landfill facilities suitable for disposing CCPs is on the increase due to the less onerous water requirements associated with Dry Landfilling practices.

Recent developments in South African environmental protection legislation now require than all new CCP landfills be designed in accordance with the Waste Classification and Management Regulations (WCMR 2012) and subsequent gazetted documentation which imposes the requirement for an engineering barrier protection system to protect the underlying aquifers and surrounding environment.

A literature review on the behaviour of coal ash waste compared to municipal solid waste (Wallace, 2013) highlighted the potential for the generation of excess heat in the ash waste due to the pozzolanic reaction that can take place when CCPs are hydrated post placement.

The review further highlighted a gap in the understanding of the geotechnical behaviour of CCPs when they are landfilled as a homogenous, consistent waste material.

Download technical paper here.