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National Science and Technology Forum (NSTF)

ROC Water Technologies

For the the research and development of processing of liquid and solid wastes from the mining, power station and fertilizer industries to recover water of drinking quality and saleable products.

(Sponsored by the National Intellectual Property Management Office (NIPMO) since 2019)

The winner of the 2022/2021 Innovation Award: SMME was ROC Water Technologies, funded by THRIP (Department of Trade, Industry and Competition), the Water Research Commission and the Innovation Hub, with support from postgraduate students at the University of Limpopo, Tshwane University of Technology and the University of Pretoria. They developed a series of technologies that allow the processing of liquid and solid wastes from the mining, power station and fertiliser industries to recover water of drinking quality and saleable products.

It has also led to the development of saleable products such as pigment and aluminium sulphate, sodium carbonate, calcium carbonate and sulphur.

Technology turns waste and solids into potable water in a country that needs it urgently

ROC Water Technologies is a project funded by The Technology and Human Resources for Industry Programme (THRIP), the Department of Trade Industry and Competition (DTIC), the Water Research Commission (WRC) and the Innovation Hub. It is supported by postgraduate students at the University of Limpopo, Tshwane University of Technology and the University of Pretoria. It has developed a series of technologies that allow the processing of liquid and solid wastes from the mining, power station and fertiliser industries to recover water of drinking quality. It has also led to the development of saleable products such as pigment and aluminium sulphate, sodium carbonate, calcium carbonate and sulphur.

“An unfortunate consequence of South Africa’s vital gold and coal mining industry is the formation of acid mine water that threatens to pollute scarce fresh water resources,” says Professor Johannes Maree, Director: ROC Water Technologies and Professor at the Department of Water and Sanitation at the University of Limpopo. “This development is of great value to South Africa as it can be applied to treat the approximate 350 megalitres of acid mine water formed per day in Gauteng at gold mining operations, and about 200 megalitres per day in Mpumalanga at coal mining operations.”

 

The team believes that mine water can be treated to not only recover drinking water, but the pigment is now being exported by South Africa and is selling for about R40 per kg. The income generated by the sale of the water and the pigment, as well as the other saleable products, covers the cost of the treatment and neatly bypasses the disposal costs of solid and liquid waste. This aligns neatly with current legislation that demands zero waste — a mandate that means waste streams have to be transported and disposed of at toxic waste disposal sites at a cost of R2 000 per tonne.This technology is also of value to coal power stations, where SO2 (sulphur dioxide) emissions have to be controlled. Calcium carbonate is used for the removal of SO2 from flue gas by forming gypsum, and can be recovered from the gypsum using thermal treatment.

“The ROC — reverse osmosis/cooling — process can treat acid mine water to recover these elements across various stages of these processes,” says Maree. “The main focus of ROC Water Technologies is to protect the environment in a cost-effective way. The focus is on economic growth and the environment, not one or the other.”

The ultimate goal for this extraordinary project was to implement innovative technical solutions that provide cost-effective answers to waste stream problems. ROC Water Technologies has achieved this goal with the help of postgraduate students, organisations, and government bodies. It overcame significant challenges in the process of transforming acid mine water into drinking water and various other components, but it ultimately succeeded, and this has significant value for the mining, fertiliser and power industries. — Tamsin Oxford

Read the special Mail & Guardian supplement about all the NSTF-South32 Award winners.

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