Nature-based technologies for Africa wastewater challenges

Close to 80 per cent of wastewater generated by households, cities, industry and agriculture flows back into nature without being treated or reused, according to the United Nations’ 2017 World Water Development Report. This is not only an issue for the environment but also a major health threat to the world´s growing population.

To address the problem companies and researchers in Africa are seeking affordable and sustainable wastewater management solutions to prevent death and illness, and in so doing improve overall human wellbeing. The infrastructure for the management and treatment of sewage and wastewater is inadequate across much of Africa. For example, only 26 per cent of South Africa’s sewage, which is processed by 1 000 municipal wastewater treatment facilities, is adequately treated before being discharged into natural water bodies such as rivers and lakes. Globally, but especially in developing countries, broken and non-existent pipes are allowing sewage to contaminate drinking water, fuelling disease and death.

An estimated 1.8 billion people worldwide depend on water sources that are contaminated with human excreta, causing outbreaks of fatal but often preventable diseases. Contaminated or unsafe drinking water, poor sanitation and inadequate hygiene lead to 842,000 deaths every year, the bulk occurring in sub-Saharan Africa.

Over the past years, numerous technologies have been developed around the world to treat wastewater, among them are biological solutions that use the appetites of algae.

The Council for Scientific and Industrial Research (CSIR), a South African research and development organisation, has successfully implemented an algae-based wastewater treatment solution in the Sekhukhune District Municipality of Limpopo. This is one of the country’s poorest provinces, and hardest hit by South Africa’s wastewater crisis.

In six sequential treatment ponds, cultured algae species are used to create unfavourable conditions for pathogens such as Escherichia coli by increasing the pH level of water.

“One issue we are dealing with is the pollution of our surface water resources,” says Marius Claassen, CSIR’s aquatic ecologist in a video interview with Popular Mechanics, explaining that the wastewater infrastructure in Sekhukhune District is ageing and no longer suitable to process the growing volume of waste. “The algae in ponds one to five are consuming the nutrients coming into the ponds with the effluent. In the sixth pond the water is what we call polishing and prepared for final release into the rivers.”

Solutek – a liquid derived from kelp species – cleans up the water by stimulating the reproductive rate of beneficial aerobic bacteria. This allows these bacteria to become dominant, out-competing undesirable organisms which would otherwise use the same food source to generate bad odours and other problems. Solutek helps counter the formation of hydrogen sulphide which, besides smelling bad, is also one of the key agents for the corrosion of steel and reinforced concrete in treatment systems.

Developed by a private enterprise, Solutek turns wastewater, including sewage, into a product safe enough to be released back into the environment.

“Solutek is a 100 per cent biological product that can treat the content of septic tanks. Many people use chemicals but we are not comfortable with that. Chemicals at some point will get back into your drinking water,” says co-founder James Brasden of the private enterprise.

“Our product works with any organic matter and is perfectly suitable for septic tanks and other sanitation facilities in remote areas,” Brasden says. “You only need a few millilitres per toilet or septic tank per week.”

Another water purification company, Bluewater, has also worked on its own water treatment solutions. It has developed a device that turns almost all types of water into clean drinking water.

This solution is being used during the 2017/2018 Volvo Ocean Race to provide sailing crews and spectators with drinking water. It does so by treating non-potable water and turning it into water that is safe to drink. Besides that, the machines could technically make sewage water safe enough to be released into the environment.

“We can treat almost any water, except sea water. We do not desalinate, but we can do brackish water,” says Anderson, the company’s chief executive officer, adding that the machine´s membranes catch everything, including some pathogens. This means it could be used to turn sewage water into water for irrigation or water that can be released back into the environment.

Besides being able to use almost all kinds of water, Bluewater’s machines have a high yield of 8 000 litres per day, which could serve smaller to medium-size settlements of a few thousand people with little waste.

“Normally, for every ten litres of polluted water you will get one litre of drinking water,” says Anderson. “Our technology has a 70 – 80 per cent clean water ratio. This is achieved with little energy. That is why the solution is suitable for Africa, an energy-starved continent. It can be connected to solar panels with battery storage,”

One of the key challenges in turning these and other alternative wastewater innovations into mainstream solutions is changing people’s minds around wastewater and where potable water should come from. This is particularly the case in developing countries where water recycling for drinking water is not common place.

*Miriam Mannak is a freelance journalist based in South Africa.

This series of news articles is part of the Wastewater Management and Sanitation Provision in Africa Project, a partnership between the African Development Bank (AfDB), UN Environment and GRID-Arendal. The project is supported by the AfDB through its Rural Water Supply and Sanitation Initiative (funded by the Governments of Burkina Faso, Canada, Denmark, France, Italy, Switzerland and the Netherlands), and the Multi-Donor Water Partnership Programme (funded by the Governments of Canada and Denmark). The project is also funded by the Government of Norway and UNEP, and technically supported by GRID-Arendal.