They say the next world war will be fought over access to fresh water, but here in South Africa we are in the midst of our own fight: to guarantee drinkable water for the coming years. The ever-growing threat posed by Acid Mine Drainage (AMD) has gradually – and then very suddenly – come to the fore in the water reticulation sector. Research into bioremediation, in particular, has shown links between AMD and municipal wastewater (MWW) treatment, and might provide the solution to an extremely complex problem.

In early 2011, Greenpeace featured a story on AMD warning that “[t]he flow of AMD into South Africa’s surface and ground water systems is having devastating consequences that are both far-reaching and long-term.” Two years later, decisive action has yet to be taken by the government.

There may be rising financial implications for each day that action is not taken, making the R94 million already spent by the Department of Water Affairs a mere token. The Trans-Caledon Tunnel Authority – hired by the department to address the water crisis – has provided an initial estimate of more than R2.2 billion.

General consensus amongst environmental groups, such as the Federation for a Sustainable Environment (FSE), is that the government has approached AMD in a haphazard and shortsighted manner. There are concerns about the lack of mobilisation and incentives to solve the crisis. AMD is an issue that can be approached from many angles, but it seems that political action has failed to consolidate research with a view to implementation.

One promising area of enquiry is that of bioremediation – the use of micro-organisms to remove contaminants in water. Since it involves naturally occurring phenomena, bioremediation can happen without human intervention, but in the scientific context, these natural processes are exaggerated for a particular purpose. Scientists have even gone so far as to genetically manipulate organisms to perform a specific function.

Fungi and algae have successfully been used to treat industrial waste, and some researchers have been experimenting with these organisms in the context of AMD. They have the potential to counteract the high levels of acidity associated with AMD-affected water.

Dr Hlanganani Tutu of the University of the Witwatersrand’s School of Chemistry has been conducting research in this area for several years now. “Algal and fungal biomasses can actually take up pollutant metals from water,” Tutu explains.

But it’s not as straightforward as that, he warns. AMD water is characterised by low pH levels and a high concentration of metals, which eliminates the possibility of many forms of life, including most algae and fungi. In treating AMD-affected water, the high acidity precipitates the need for what is known as mutualistic relations, i.e. cultivating algae or fungi with something to bolster their ability to survive and to perform their function more effectively.

“When you culture [the fungi] in an amenable support medium, you tend to increase the amount of biomass,” says Tutu. For example, growing fungi in a bentonite (clay) matrix before it is added to AMD-affected water is far more effective than using the fungi or bentonite on their own.

In South Africa there seem to be just a handful of people working with fungi and algae in relation to AMD. Tutu says that there have been “promising results” and that there should be “more emphasis” on this area of inquiry.

The Council for Scientific and Industrial Research (CSIR) – the largest research and development centre in Africa – apparently has little interest in such developments. When contacted for information, CSIR’s senior research chemist, John Zvimba, said neither he nor any of his colleagues had knowledge of this area of inquiry.

There is no abundance of literature concerning international research in this field, either. One promising paper from the Indian Institute of Technology Kharagpur called Occurrence and role of algae and fungi in acid mine drainage environment with special reference to metals and sulfate immobilization has explored similar questions, and states that the roles of algae and fungi “are not emphasised adequately in […] mine water research.”

In response to this, Tutu points out that there are “many possible approaches to the AMD problem,” and that one will find pockets of research across the country. With regards to removing heavy metals and neutralising pH levels, he names other methodologies such as using lime or limestone, polymeric resins, and other natural substances like clay and zeolites.

But bioremediation comprises far more than just fungi and algae, and there are other areas of AMD research that may benefit from the use of different micro-organisms. According to author and AMD expert Professor Terence McCarthy, the removal of heavy metals is only the starting point in treating AMD-affected water. “Adjusting the pH level is only step one,” he says. “The big problem is to get rid of the sulphate.”

The World Health Organisation has released studies on the toxicity of high levels of sulphate in drinking water (low levels are unavoidable), and links it to diarrhoea and dehydration.   

Bioremediation has proved useful in removing sulphate from water, though without the use of fungi or algae. Instead, sulphate-reducing bacteria (some of the oldest forms of life) that operate in anaerobic environments (i.e., those environments without oxygen) can “consume” sulphate, leaving hydrogen sulphide behind (which itself needs to be dealt with, usually by chlorination).

There is a far bigger body of research behind this form of bioremediation. McCarthy identifies one particular process developed by Rhodes University – the Rhodes BioSURE process – as having a significant impact on AMD in South Africa.  

The process uses partially treated or untreated MWW, which contains sulphate-reducing bacteria, to treat water high in sulphate. In other words, it so happens that combining two of the most problematic instances of water pollution – AMD and MWW – seems to resolve at least one obstacle in treating AMD-affected water.

A 2012 paper entitled Co-treatment of acid mine drainage with municipal wastewater: performance evaluation makes the case for co-treatment, claiming that it’s not just the reduction of sulphate levels that could be resolved: “In theory, co-treatment of AMD and MWW should be highly effective, because compounds that are high in one effluent stream tend to be low in the other.”

However, McCarthy warns that there are further implications to the BioSURE method. The treatment itself leaves a substantial waste stream, and this provides a further complication. “What do you do with the solid waste?” he cautions. And with the volumes of water that requires treatment, there would be substantial waste.

In response to this dilemma, water treatment company P2W announced the results of a 12-month research project at the 2013 Mining Indaba earlier this month. It is claimed that the technology can be used to treat water directly from the underground basin, and would not require the (separate) removal of metals as discussed above. The process is said to yield less waste than other methods, but there will still be enough to warrant concern.   

For every solution offered, another problem seems to emerge – although they are not new, and not unique to this country. “It’s a worldwide problem, not a South African problem,” says McCarthy. “People have tried to address this issue [for centuries], going back to Roman times.”

Nevertheless, we are dealing with the here and now. The most vulnerable areas are those located downstream of the Vaal river, towns such as Postmasburg and Welkom. Johannesburg itself is not particularly at risk, and one wonders if this fact has affected the course of action. Might we have seen swifter, more succinct strategising if this weren’t the case?

Tutu points out that the problem is not restricted to the gold mines in Johannesburg, which are the focus of the AMD crisis. “You have AMD from coal mining, and if you think of the copper mining in the Limpopo area, there’s AMD there as well. To some extent, some iron mines are also problematic.” According to Tutu, such regions could prove to be “even more serious” an issue.

He warns that we are moving closer and closer to a real water crisis. “The longer we delay, the more danger we are putting ourselves in. By the time everyone wakes up, it could be too late.”

Tutu suggests that AMD hasn’t risen to top of the political and media agenda because access to water is taken for granted. “The issue of water is not treated the same way as the issue of energy,” says Tutu, making a comparison with climate change campaigns. “If we were having a discussion about research that could help sequester carbon dioxide, we could come up with a plan and by tomorrow we might have huge funds channeled to our research.”

But there are also more practical difficulties when it comes to AMD. “The type of research we do is multi-disciplinary,” Tutu explains. “Chemists work with microbiologists and geologists. It’s not always possible to be involved with projects like that. Some institutions have their microbiologists working alone, for example. So that might be stifling the research.”

McCarthy, on the other hand, is adamant that the government is sufficiently concerned about AMD, but he also urges the general public to take cognisance of their role in the situation: “We all reap the rewards of mining, but then there’s the downside. We tend to ignore it and hope the problem runs its own course. In the meantime, things could get really difficult.”

With the clock ticking we can expect further flurries of media interest in AMD and further calls to action. The question is whether the variety of approaches to the crisis – and their respective consequences – can be assessed and streamlined into a concise plan of action that will work both now and in the long term. Until then, we will be fighting our own unique fight to keep our taps running with clean water.