After decades of steady decline, world hunger is on the rise. An estimated 821 million people in the world suffered from hunger in 2018, and Africa remains the world’s most food-insecure region.
Similar to urban slums around the world, Zimbabwe’s densely populated slum of Mbare faces several challenges that affect the community’s access to food. These include lack of sufficient space to grow crops, insufficient knowledge around how to use technology to improve farming, high levels of unemployment, and low levels of interest in farming, particularly among youth.
In response to such challenges, a team of students is piloting an innovative solution: aquaponic urban farming using the Internet of Things (IoT) to increase food self-sufficiency in Mbare. The project, led by the Internet Society Zimbabwe Chapter with support from the University of Zimbabwe, St Peter’s High School Makerspace and the I Am Mbare Youth Development Centre, kicked off in 2018 with a $30,000 grant from the Internet Society Foundation’s Beyond the Net Programme.
A 2-metre-tall collection of freight-container-like structures, water pumps, pipes and granite flowerbeds sits in an empty lot outside the University of Zimbabwe’s Chemistry Department. Tiny fish swim in the tanks alongside various potted plants that will soon bloom into rapeseed, strawberries and spinach.
Aquaponics combines aquaculture (raising aquatic animals such as fish) with hydroponics (cultivating plants in water), in a mutually beneficial environment. The two components interact via the water that cycles between them. As plants and fish grow simultaneously, fish waste is converted into nitrates, which plants use as fertilizer while they filter and clean the water for the fish.
In Zimbabwe, students at the Mbare Makerspace have taken it one step further, setting up their aquaponics system to be monitored by IoT. Among the simple but powerful devices used are an Aurdino Uno micro-controller, which serves as the brains of the operation; sensors that detect changes within the system; a cluster of Raspberry Pi single-board computers, operating as a mini-data centre; and a long-range network that glues together the aquaponics units.
The micro-controller controls the fish tanks, sending data through its sensors to computers housed in the student’s lab. Whether they are on-campus or 10km away in their Makerspace in Mbare, the students receive important alerts about the system, such as the water temperature, pH levels, and whether the tanks are having problems such as leaks. This set-up allows constant monitoring through data sent in real-time to a laptop or mobile phone.
“Building aquaponics systems is easier now through YouTube tutorials. However, this information is not accessible to most people in Mbare. This grant has enabled us to design a scalable model which we will use to teach the community how to set up their own systems in a cooperative way, ultimately enabling them to grow their own food on a large-scale.”Solomon Kembo, Aquaponics project manager and software engineering lecturer at the University of Zimbabwe.
In building this model, the team made several adjustments to accommodate their unique environment. They used solar panels to take advantage of the abundant sunshine in Zimbabwe and bypass the country’s unreliable electricity supply. The system itself was built tall instead of wide, in order to take up the least amount of space and mirror the environment in Mbare, where people live in cramped quarters with small front yards.
“We’ve loaded our project’s code onto an open-source platform, GitHub, so we can learn from the best and allow other interested people to replicate our work”, says Gabriel Matemba, one of the student project leaders, who calls Mbare home. Beaming with pride, he displays the 2nd place award he received on behalf of the team after presenting the aquaponics project at the 2019 Clean Tech Competition, a prestigious research and design challenge for high school students held annually in New York City.
The computer lab where students monitor the system was created in 2016 through a previous Beyond the Net grant, laying the foundation for the aquaponics project. A tight camaraderie exists among this student team, some of whom live in Mbare while others hail from other parts of the city. United by a common passion and talent, they work as a collaborative team; teaching each other different coding languages and cheering each other on.
“I love coming to the Makerspace, because we use technology to solve serious problems that our community faces, while learning so much from each other and our advisors every day.”Perpetual Sanyangore, a recent graduate of St. Peter’s. She continues to visit the Makerspace regularly while awaiting the outcome of her University applications.
With the testing phase now complete, the next step is to establish a fully functional aquaponic urban farming unit in the community, targeting Mbare widows and child-headed families as first-phase participants. Participants will be trained to use data and the Internet to monitor the system, then apply that knowledge to raise fish and vegetables for their own consumption, as well as surplus for sale. Long-term, the hope is that more community members will be inspired to take up aquaponic urban farming – tackling food insecurity and ultimately creating more resilient and sustainable urban communities.