It’s a winning season for the National University of Lesotho (NUL)! This time it is the NUL Masters of Sustainable Energy student, Ntšebo Sephelane, who, along with her team, have just won the Austria’s Management Centre Innsbruck (MCI) Winter Program Award for the outstanding project idea in Sustainable Energy.
“The project, which took the first position in the competition, is designed to solve problems caused by burning of fossil fuels, generation of food waste and eutrophication,” Ntšebo said.
Eutrophication happens when a body of water becomes too enriched with excess minerals and nutrients to encourage two much growth of plants which suffocate water bodies with lack of oxygen.
The cities for which the project was designed are Maseru in Lesotho, Newcastle in Australia and Odense in Denmark. Her team included two other students from Australia and Demark.
“We studied the problems common to these three cities and came up with a ‘one size fits all’ design that could be applied by any of them,” she continued. In the eyes of the judges, the project was so brilliantly designed, Ntšebo and her team had their work judged as the most outstanding among all the submitted projects; hence the award!
Ntšebo is a Masters of Sustainable Energy student at the NUL. Not long ago, we reported that she and three others from the same NUL program left for Austria after being selected by Austria’s esteemed Management Centre Innsbruck (MCI) to spend four and half months (a semester) there studying the “nuts and bolts” of bioenergy.
Their adventure in Austria was funded by the Austrian Agency for International Cooperation in Education and Research (OEAD) and Centre for International Cooperation and Mobility (ICM).
In there, they joined a program called MCI Winter program. They were not alone. They had a team of brilliant students from the most distant corners of the earth in the program.
When it was all over, it was time to test their thinking abilities, how they would use the concepts they learned, to design sustainable solutions for world cities.
Ntšebo and the team had an idea which we shall try to present in as simple the terms as possible.
Since you probably know more about Maseru than any of the other cities, let’s think about it. First, the city’s main sewerage treatment plant might have waters prone to a problem of eutrophication according to a recent study by NUL scientists.
The city also has a problem of waste food. If you go to Ha Tšosane Dumpsite, it will not be uncommon to see truckloads of waste food being dumped in there.
And the city uses some fossil fuels to get by with daily activities (a quick example is a methane gas most people use for cooking).
Remember, while half of our energy needs are met by ‘Muela Hydro Power Plant, which gives out renewable energy, we import another half of the electricity, and it may come from the burning of coal, a fossil fuel.
So Ntšebo and her team’s job was to design a system that would turn these three problems: food waste, eutrophication and fossil fuels into opportunities by combining them into a solution.
This is the design.
When you treat sewerage, as in the case of Ratjomose Waste Water Treatment Plant, the end result of that treatment process is a material called sludge which is sometimes used by farmers as fertilizer. The sludge can also be used to make biogas. “However, sludge is not an effective producer of biogas when used on its own,” Ntšebo said. “But if you mix it with other forms of biomass such as food waste, then your biogas production becomes efficient.”
That mixing of sludge with food is called “co-digesting.”
Their design has an alternative. In this case, “instead of using food waste for co-digestion with sewerage sludge, we use algae.””
To understand why we need algae, let’s first talk about why eutrophication is a problem. Waste water treatment plant at Ha Ratjomose seeks to put acceptable kind of water into the Mohokare river, after separating it from sludge. However, if there is too much nutrients in that water (which causes eutrophication), it is not acceptable to put such water into the river.
Unfortunately, the detergents we normally use in our homes find themselves in the the treatment plant, providing more nutrients than is needed, increasing the risk of eutrophication.
Grow algae in water treatment ponds. If you do, the algae will not only use the nutrients for its own growth purposes, it will itself become another great material to co-digest with sludge to make good biogas.
Ntšebo and Co’s design is such that the biogas produced, either by co-digesting with food waste or with algae, is burned to produce electricity to power the waste water treatment plant itself. In that way, the plant won’t have to depend on electricity generated from fossil fuels.
The design hit three birds with one stone—and it won the race.