The treatment of mine water and wastewater will be a specific focus of the inaugural IFAT Environmental Technology Forum Africa, scheduled to run from September 15 to 18 at the Johannesburg Expo Centre.

This new sector platform will host suppliers as well as innovative solutions and technology users in the water, wastewater, refuse and recycling market.

Trade show company Messe München International – which is organising the forum – points out that, according to Water and Sanitation Minister Nomvula Mokonyane, South Africa requires investment of about R670-billion over the next decade to modernise its water and wastewater infrastructure.

In addition to the challenge of renovating dilapidated pipe systems and developing new municipal treatment plants, the country is also faced with the challenge of dealing with the heavily polluted water runoff from its mines.

Acid mine drainage (AMD) is the main contributor to this problem.

“The highly acidic waste- water contains significant amounts of heavy metals, which are produced when water floods into disused mine shafts, a problem that is particularly prevalent in South Africa’s gold sector. AMD can also seep from spoil heaps and, if nothing is done to address the problem, AMD will severely pollute both surface and groundwater.

“The failings of the past, such as a lack of legislation to enforce proper mine wastewater discharge and treatment, have led to the polluted wastewater from mines becoming an evermore urgent environmental problem for South Africa,” Messe München notes.

However, there is a range of treatment solutions available from international environmental technology companies to tackle the challenges of mine wastewater. These include ventilation, precipitation and ion- exchange processes, components for membrane- and nano-filtration, reverse-osmosis plants and solutions for biological sulphate removal.

In addition to these solutions, mines can install accompanying equipment such as pumps, pipes and measuring devices.

The combination of technologies used to treat mine wastewater will, however, depend on the composition of the wastewater, which varies significantly in different mining regions, Messe München says.

The company notes that, in the past, South Africa’s mine water treatment processes generally concentrated on neutralising low pH values and removing metals. However, this still leaves significant amounts of salts in the water and, according to a South African commission of experts, it is important in the medium to long term to treat the increasing salt levels found in mine waste- water as well.

By doing this, it would be possible to help alleviate the water shortage in the country and a few flagship projects are already in operation that produce potable water from active coal mines by processing mine wastewater in desalination systems. The treated water is then fed into municipal networks.

According to information from economic development agency Germany Trade & Invest, plans are under way to use large modern desalination plants to produce potable water from AMD in several of South Africa’s mining areas, including Johannesburg. The disused mine shafts could then be repurposed to serve as underground water reservoirs that could cover an estimated 5% of the overall water demand in the region.

The inaugural IFAT Environmental Technology Forum is expected to have exhibitions from about 60 environmental solutions providers and attract about 2 000 visitors.