Waste management is not only fundamental to the sustainability and legal compliance of a mine but it also has larger-scale, industry symbiotic economic benefits through enforcing and contributing to a circular economy-based business model.
As mines look to reduce their carbon footprint, the opportunity for mine-related waste-to-energy projects in South Africa is rising, says waste management solutions provider Interwaste marketing director Kate Stubbs.
The company
states that, while these projects are not all ready for implementation yet, there is “definitely a move towards exploring and identifying the opportunities that waste presents”.
Industries needs to look beyond using fossil fuels and find alternative energy sources, such as waste-derived fuel, and waste could play a significant role.
The mining industry in South Africa is embracing change, with several mining houses announcing their future investments in solar and wind production plants, says Stubbs.
However, she advances that mines are continually looking for ways of disposing their waste responsibly and, coupled with waste’s capacity for power generation, refuse-derived fuels (RDF) is a feasible option.
Larger waste-to-energy plants using thermal destruction technologies exist and are in operation in many countries. Even though the cost of energy production per kilowatt hour from waste plants is higher, compared with solar or wind energy, the benefits include a reliable energy supply as the plants can run 24/7.
Moreover, using waste as an input material for energy, rather than being disposed of to landfills, provides social, environmental, and economic benefits; with mines not having to spend capital on waste removal.
Two types of RDF have been pioneered locally at Interwaste, one solid and one liquid, continues Stubbs: “We have been successful in taking a solid fuel source, which is recovered through the shredding and bailing of certain presorted, dry industrial nonrecyclable waste, and creating a fuel source that is similar to A-grade coal”.
Further, South African and other African mining companies are becoming more receptive to effective waste-management solutions and programmes on offer.
“In the waste sector, we have already started driving such innovations to other energy sources and these also support the National Waste Management strategy to divert waste from landfill disposal,” says Stubbs.
Many global mining companies are moving towards a zero-waste-to-landfill target and are examining ways in which they can effectively repurpose waste through using and developing advanced technologies, thereby ensuring waste-to-energy can be realised, she emphasises.
The National Waste Management Strategy 2020 has the concept of the circular economy at its centre. It is premised on three pillars which will see a future South Africa with zero waste in landfills; cleaner communities, well managed and financially stable waste services, and a culture of zero tolerance of pollution, litter and illegal dumping.
Stubbs comments that legislation can play a crucial role for green energy providers. Government is committed to redirecting waste from landfills and, in support of this, new laws aimed at cleaning up South Africa and reducing the negative environmental and health impacts caused by waste have been promulgated.
She explains that the circular economy model offers opportunities to deliver inclusive economic growth, combining job opportunities with positive environmental practices.
Other means of converting waste to energy include thermal destruction, gasification, pyrolysis, anaerobic digestion and landfill gas recovery.
Organic waste processed in anaerobic digesters is used to produce a methane-rich combustible gas that generates electricity. The anaerobic platform also diverts organic waste from the landfill, which, in turn, reduces the releases of harmful greenhouse gases.
It will become critical for miners to incorporate their environmental impact into the business processes – from inception and throughout the life cycle of the mine, she claims.
From the sourcing of various raw materials to the production and final consumption, companies must understand the generation of waste in every process to ensure the long-term commercial and environmental viability of the business, Stubbs concludes.