By Vianney Tumwesige
Farmers in Uganda and in developing countries around the world are facing major energy and waste management issues. There are anaerobic digestions systems to help farmers manage agricultural waste from plants and animals, but there’s a problem. These systems require a large amount of water to function, and water scarcity is already a major issue for these farmers. At Green Heat Uganda, we found a way to create a waste management system that uses less water, while tackling other problems like deforestation and air quality.
Historically, anaerobic digestion systems enable microorganisms to break down biodegradable material and then produce biogas. Waste and water go in, and fertilizer and biogas — which turns into heat and electricity — come out. The problem is that for every kilogram of waste, it needs to be mixed with a kilogram of water. In other words, women and children in Uganda might need to gather upwards of 80 liters of water every day just for the digester. This arduous burden leads to half of standard digesters being abandoned within a year. These systems are a sinkhole for labor and resources and are, as a result, unsustainable.
As a student of engineering and environmental science, I founded Green Heat Uganda in 2011 to develop a new kind of system. Our digester uses a gravity flow filtration system to separate the slurry — the mixture of waste and water — into solid fertilizer that farmers can use on their crops, while recycling used water back into the system for continued use. So far, our digester has reduced water usage by 85 percent and has saved more than 1.8 million liters of water to date. Furthermore, the biogas cuts down on wood and gas needs for cooking and electricity.
This efficiency is what makes Green Heat innovative. It’s a solution that requires farmers to put in less labor and fewer precious resources, while producing cleaner outputs for its users. Today, we’re working to create a larger demand for our product while driving down costs and creating a payment system to expand access for the average farmer. It’s all part of helping Africa — and the world — achieve a bright future of renewable energy, food, and water security.
Vianney Tumwesige is the founder of Green Heat International, a company focused on sustainability issues like deforestation, air quality, energy, and waste management. Green Heat works to raise awareness in the political, economic, and social framework of Uganda’s energy sector.
Green Heat Uganda is a grantee of Securing Water for Food: A Grand Challenge for Development. SWFF aims to increase access to innovations that help farmers produce more food with less water, enhance water storage, and improve the use of saline water and soils to produce food. Over the previous two years, the program through its innovators has saved over 2 billion liters of water, produced nearly 3,000 tons of food, and served more than one million farmers and other customers in more than 28 low-resource countries.