Mama Justice doesn’t let her age slow her down. At 70 years old, she runs a small pig farm in Buwambo, Wakiso District in Uganda. And until recently, she gathered firewood every day to cook each meal for her four grandchildren. Mama Justice is a fantastic cook — easily whipping up meals of banana-like matoke, and cassava and groundnut paste with fish after her many years of practice. And she takes pride in her kitchen, even though the smoke from the firewood often made it difficult for Mama Justice and her grandchildren to breathe in her small home.

After 70 years of hauling firewood, Mama Justice was beginning to struggle with the physical burden. A friend suggested that Green Heat, a social enterprise based in Kampala, could help. The Green Heat team recommended that she could use an anaerobic digester instead of firewood. Anaerobic digesters use biodegradable waste, such as plant leaves and livestock manure, to create clean-burning fuel. Microorganisms and bacteria break down the waste in a dark, oxygen-starved environment, until the mixture has fermented and renewable gas is produce

Vianney Tumwesige, the managing director of Green Heat, and his team informed Justice that the digester could pipe clean gas directly into her kitchen — eliminating her reliance on firewood and ridding her home of dangerous smoke. The innovative Green Heat digester would also help her conserve water, saving her time-consuming and backbreaking trips to the well multiple times a day.

“Green Heat’s digester recycles water back into the system,” explains Tumwesige. “It’s better for the environment and less work for the farmer to maintain.”

Mama Justice had never used waste from her pigs as a source of energy before, and she had her doubts. As the cook responsible for feeding such a large family, she needed a reliable source of fuel. And she was concerned that cooking with a different kind of fuel would change the taste of her food. Justice wanted to know that her beloved recipes wouldn’t change when her fuel source did. Tumwesige assured her that her food would remain delicious.

It took some patience. First, Mama Justice had to invest in a few more pigs to provide enough manure to power the system. Then the digester needed several months to begin breaking down the waste and start filling the fuel tanks. In all, it took about 3 months and 2,000 liters of waste to get the system up and running at full capacity.

Then came the true test. Mama Justice set up at her new gas stove, with its shimmering blue flame, and set to work peeling onions, adding tomatoes and making her “famous green sauce.” It took over an hour to prepare, but when she was finished, she took a large spoon and tried the sauce — cooked for the first time with clean gas. The food tasted delicious, as always. Best of all, she didn’t have itchy, watery eyes like she usually did after an hour spent laboring over a hot, wood-burning stove!

Mama Justice was so excited she invited the whole Green Heat team to stay for lunch.

All her life, Mama Justice had endured problems from the smoke in her kitchen — coughing, wheezing, and enduring eye pain. The Green Heat anaerobic digester not only brought energy into her home using the waste she was already producing and eliminated her need to gather wood; it provided a healthier environment for her to cook for her family.

And as she teaches her recipes to the next generation, the only tears they will be crying will be from peeling onions — not from smoke.

The Hattaway team co-created this story with Green Heat and Securing Water for Food, an organization working with entrepreneurs and scientists around the world to help farmers grow more food with less water. To learn more about Green Heat, visit them on Facebook.