Q&A: Bart Van der Bruggen on designing water purification systems

Is access to drinking water problematic in South Africa?
South Africais a country with two faces. The large cities, especially in the western part of the country, have a good infrastructure. But in more rural parts of South Africa, the supply of drinking water is often inadequate. I admit that the situation is worse in many other African countries, but that’s also the reason we chose to realise this pilot project in South Africa. Thanks to the country’s leading place in terms of infrastructure, we could rely on existing expertise, such as working with a South African engineering company. But in the long term, our goal is to export the technology to countries north ofSouth Africa.

The design of the purification plant looks quite simple.
It’s not. The plant relies on the process of gravitational filtration, in which the force of gravity is used to push water through a series of filtering membranes. You could compare it with a coffee percolator, but the membranes are not so easy to find and install. But this process means that the plant doesn’t need external energy, and it doesn’t produce any waste material. To allow gravity to act on the water, however, we need a certain difference in altitude. 

In Durban, there have already been some similar projects, but these didn’t go beyond the demonstration phase. But the true innovation here lies in the integration of water management into the local communities that use it. The local people decide on the maintenance, use and financial aspects of the plant. Users also have to pay a small fee. A free system doesn’t work, as it leads to abuse.

Your actual field of research is separation technology. How did you get involved in this project?
Separation technology also includes physicochemical separations in water, which can be applied in drinking water, waste water, etc. I consider a development context to be an essential part of any academic’s work, but it comes in second to economic profit in science and technology these days. As a member of the Flemish Interuniversity Council, I’m also involved in similar projects in Tanzania, Uganda and Ethiopia.

photo: Bart Van der Bruggen pictured with fellow KU Leuven researcher Patricia Luis