SPOTLIGHT | Black Soldier Fly

empties toilet bowls in Mozambique


Toilets and innovation: these two words may not automatically couple together, even more so when the innovation consists of a fly. It’s the poop-eating larvae of the Black Soldier Fly, however, that help families in Mozambique to a better toilet – with help from VIA Water and Aqua for All. How does this work? On World Toilet Day, we put the fly-toilet in the spotlight.

It all started in 2016 in Polana Canico, a neighborhood near the modern city center of Maputo. Most of the Polana Canico residents have water and electricity, but no sewers. Oftentimes, you’ll find a simple latrine in the yard: a concrete-covered hole in the ground with a little house above it. At some point, the latrine will be full and people will have to rent a suction dredger, or someone who will scoop it out. Or they build a new latrine. In the densely-populated neighborhood of Polana Canico, however, there is not enough space for that.

The idea to use poop-eating flies comes from Bjorn Brandberg, a 76-year-old Swede who has lived in Mozambique for 40 years. In 2014, he read a dissertation on the Black Soldier Fly. In this dissertation, the idea was suggested to construct a latrine with larvae that clean up the poo. Bjorn picked up the gauntlet together with Dutch consultant Annemarieke Mooijman and a team of four enthusiastic Mozambicans.

The idea is simple: shovel the larvae in a latrine and let them feed on the human excrement. This will keep the latrine as good as empty. The larvae turn into flies that mate in the latrine, allowing for new larvae to do their work. Occasionally you’ll need to add some new larvae.

Harmony with nature

The innovative ‘fly toilet’ fits perfectly within the theme of this World Toilet Day: ‘toilets in harmony with nature’. Today, 32% of the people in the world do not have access to a decent toilet. In 2000, that number was still 42% of people. This means that more and more people are getting access to a good toilet, but that this growth is still too slow to achieve SDG6 for water & sanitation.

For this reason, governments, organizations, and residents worldwide are continuing to buckle down. Video’s on the website of VIA Water show how Mozambicans are involved in the Black Solder Fly toilets. Consultant Annemarieke Mooijman: “We were looking for young, enthusiastic people, who are good with their hands, who can vlog, and, above all, who are creative and like to do things ‘differently’.

This year, twelve women and a man were trained in constructing concrete toilet bowls that only need one cup of water for flushing. The sales price of these toilets is a mere 12.50 dollars. The construction team also learned how to grow larvae, so that they can eventually sell them together with the toilets. The first ten families now have a brand-new toilet bowl with flies, another ten families have flies in their existing latrines. According to Annemarieke Mooijman, it was not difficult to convince residents of the purpose of the fly toilet: in the old latrines, there were also insects and worms. People do not think this is ‘scary’.

In December, the pilot phase of the project will be over and the company Susamati will be launched. Susamati will be selling concrete toilet bowls and Black Soldier Larvae on compost. For the time being, a complete pit latrine with larvae is not yet ready for introduction. “We want to know even more profoundly how often people have to put ‘new’ larvae in the toilet,” says Mooijman. “This number changes per season. We follow the toilets that are part of the project pilot closely for experimentation.” If the knowledge is there, however, then the fly toilet can offer a very cheap and easy solution to the needs of the densely-populated urban areas of Mozambique”.

This article appeared (in Dutch) on Worlds Best News on November 19th 2018.