South Africa will benefit from tackling the country’s water challenges by drawing on lessons from its international counterparts and neighbouring countries’ water infrastructure projects, says engineering services company VWS Envig MD Dr Gunter Rencken.
Speeding up this process is critical, given that some water scientists predict a shortage of easily accessible sources of freshwater, such as surface and ground water, by as early as 2015, he adds.
“Many areas are already approaching the balance between fresh water supply for municipal use and fresh water supply to industry. Specific areas are in drought and are approaching a crisis point where there is not enough water for human consumption,” he explains.
“South Africa has drawn and continues to draw on lessons from water systems used in Namibia, such as the large desalination plant constructed two years ago to supply uranium mines with water, with some of this water treated to potable standards for local communities. Authorities in South Africa are realising that they have to think about other methods of providing water. Rivers and dams no longer provide enough water to supply demand in many areas and new water sources include desalination plants for many coastal areas, particularly those affected by drought,” Rencken explains.
South Africa’s water challenges are also similar to those of Australia, which is investing significantly more money into water infrastructure and has constructed large seawater desalination plants, as well as looking at water reuse and recycling. Similar trends are emerging in South America, Rencken points out.
Botswana desalinates brackish underground water for human consumption. Rencken says that the challenge with this water supply is that scientists are not aware of how quickly the reserves will be refilled by rainwater. However, Botswana has to use this water because of water scarcity, and VWS Envig has built a number of brackish water treatment plants in the country.
An important water source is the reuse of municipal wastewater. Sewage goes to a common wastewater treatment plant, is treated biologically to a certain specification and can be further treated, if needed, to produce a quality of water fit for drinking, he says.
“This is becoming increasingly prevalent in South Africa. The Durban Water Recycling (DWR) project, in the south of Durban, purifies 40 000 m3/d of biologically treated municipal wastewater and sells the water to major industrial users for industrial processes. The DWR model has shown that wastewater reuse is not only technically sound, but also financially viable, changing the thinking on wastewater reuse in South Africa.
VWS Envig is part of the consortium that operates a plant that recycles sewage for drinking water in Windhoek. The plant cleans domestic wastewater to potable standards and then feeds it into the munici- pal supply. This demonstrates that cities can use unconventional sources of water for drinking water and municipal fresh water supplies, he adds.
Zero Liquid Discharge
Another important unconventional source of water is water recycling by industry. Large industrial users recycle a significant amount of water to reduce their water intake. These users are also increasingly looking to decrease the use of fresh water for industrial processes that do not require water of drinking water standard.
“The steel, mining and chemicals indus- tries, as well as State-owned power utility Eskom’s power stations, frequently use recycled water; and industries, in general, in South Africa are increasingly considering a policy of zero liquid discharge. This involves trying to avoid water discharge by reusing and recycling all water for factory use,” Rencken says.
Companies, such as steel giant ArcelorMittal and petrochemicals company Sasol, have invested significant capital in recycling process water. This, says Rencken, is affirmed by VWS Envig constructing a plant for ArcelorMittal, three years ago, that has a zero liquid discharge and recycles all the water fed into the plant. The treatment plant removes salts from the water, which are then dumped on a hazardous waste site, while the water is recycled back into the steel facility. “This zero liquid discharge project is a noteworthy achievement on an international scale,” he says.
Industrial sources of water also include polluted mine water. Many mines in Mpuma-langa and on the West Rand have significant reserves of underground mine water that are polluted with minerals and metals, which results in treatment challenges.
Construction and engineering major Aveng has a project at one of Anglo Coal’s mining sites in Emalahleni to clean mine water to potable standards.
Many of South Africa’s municipal waste- water treatment plants are not performing to acceptable water quality standards and there are several issues surrounding the performance of these plants. Contributing to the challenges experienced by munici- palities is a lack of skills for the operation of facilities and a lack of infrastructure investment over the past decade, says Rencken.
“There is also a significant lack of managerial skills and decision-making capacity in municipalities and local authorities to define projects that are needed and, once defined, to put out to tender and then award these projects.
There is also a lack of capacity to manage the financial structures required for implementation of such projects,” he explains.
“These challenges require political will to be overcome and a stronger legal arm from the Department of Water Affairs to police the country’s water infrastructure. While South Africa has an advanced National Water Act, which has all the facets and legal clauses required to take action against munici- palities and industries that transgress discharge standards, implementation is often still lacking,” he says.
There appears to be a need for more awareness of South Africa’s water chal- lenges on a political level as well as by the citizens of this country.
A lack of good-quality drinking water leads to health problems, which is serious, given the fact that many poor citizens source water directly from the rivers, where not only municipalities, but also industrial water users, discharge polluted water. South Africa does not have large rivers and this concentrates effluent into small watercourses. Hazardous materials from industrial waste streams and microbiological contaminants exacerbate challenges, because water must be disinfected and purified properly before use. People downstream have to use this water because the country is water stressed, he explains.
Rencken reports that a positive development is the marked increase in investment in water infrastructure. While investment is key, skilled individuals are also important for the operating of plants and for maintenance.
“There is an opportunity for private enterprise and local government to work together in public–private partnerships (PPPs) to deal with these water problems. The expertise of private enterprise with the local government’s infrastructure can create synergies. Private enterprise will bring technology, optimisation, managerial skills and financial skills that are lacking, and can help to upgrade plants by providing project management skills.
“PPPs can also result in uplifting communities by providing clean and good-quality natural resources, such as water. The DWR plant is a good example of a PPP that also provides employment and educational bursaries every year to students and tertiary institutions. With proper planning, each party can bring its strengths to the partnership, and government is increasingly open to such partnerships.
“The PPP is a better model for South Africa than complete privatisation, which raises the ire of national unions and narrows the scope of empowerment,” Rencken concludes.
Source: Schalk Burger, Engineering News, 16 July 2010