Clean-up drive for SA’s precious water

File picture: Kim Ludbrook/EPA

File picture: Kim Ludbrook/EPA

Published Nov 8, 2016

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Johannesburg - Public and private organisations are working together to improve the quality of water in the country, with a specific focus on the mining industry.

The Strategic Water Partners Network (SWPN) aims to improve mine-water treatment to reduce pollutants in the environment and the amount of clean water required for dilution of pollutants in mining, as well as increase the availability of fresh water.

The network believes that in areas such as the Olifants River catchment area in Limpopo, as much as 11 percent of water could be saved by the coal mining industry, to the benefit of municipalities, industry and the public.

Chamber of Mines senior executive and SWPN member Nikisi Lesufi said a process had been initiated to set water-conservation and demand-management targets for the mining sector, which would help develop accurate water balances and an online reporting system.

This was after the Chamber of Mines and the Department of Water and Sanitation started a project to develop guidelines on water conservation and demand management in the mining sector in 2012.

“We believe that with this system in place, and from a sustainability perspective, the mining sector will be able to account for every drop of water from a quality and quantity perspective,” said Lesufi.

The SWPN said that since the adoption of its collaborative model, several mines in the Olifants catchment area have begun jointly implementing strategies to manage excess mine water. This includes a collaboration between Anglo American and South32, which saw the construction of a desalination plant to ensure that excess mine water discharged into streams was acid-neutral. A desalination plant processed effluent from five of the mines to remove 99 percent of the salt, making it suitable for potable water use by municipalities.

In another SWPN partnership also involving South32, as well as the Water Research Commission, Anglo Coal and Exxaro, a demonstration project on a 60 hectare piece of land used poor quality mine water for soya bean and wheat production.

“This demonstrates the significant potential for the mining and agricultural sectors to work together to achieve food security while also contributing to the protection of water sources,” the network said.

It pointed to other innovations developed by members.

A short-term project by the Trans-Caledon Tunnel Authority to resolve the problem of acid-mine drainage in the Gauteng region was successful, and as a result, the entity had been nominated by the department to implement a long-term solution to the problem.

“It will involve further treatment of the mine water by removing the sulphates and creating water to be used in industry and as potable water, resulting in the conversion of the acid-mine drainage problem into a long-term sustainable solution by producing safe water,” SWPN said.

Another innovation was being conducted by the University of the Free State and Eskom using a non-operational coal mine in Newcastle, KZN, as a pilot site. The pilot plant was based on technology that used wood chips coated with barium to treat mine water.

Polluted water was pumped into tanks filled with the barium-coated wood chips and allowed to react with them.

“The water is being treated to almost potable standards, which provides great opportunities for use of this water by other sectors, including municipalities,” the network said.

Meanwhile, Sasol's synfuels operation in Secunda pumped water from its underground mining operations into a holding dam before desalinating it through a membrane plant in a process known as electro-dialysis reversal. It was further desalinated using a spiral reverse-osmosis membrane.

The SWPN believes that treating acid mine drainage would be beneficial in the re-use of water by the mines, agricultural production, job creation and bio-fuels.

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THE STAR

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