Biodigestors Improve Quality of Life while Protecting the Environment

Traditional providers of milk, meat and fertilizer can also be grazing fuel factories. Credit: Betsy Crowfoot

Biogas has been collected for years by major first-world agricultural entities, landfills and manufacturers, but now families in developing countries and environmentally at-risk sites also are finding the collection of methane gas byproduct can fuel lamps, ovens, and hope.
Moses and Miriam Sabiika live 20 miles from the Ugandan capital of Kampala, and the shores of Lake Victoria. Nearly a dozen years ago they received a gift of livestock via a Heifer International program, to supplement the crops that barely sustained them, their five children, and two grandchildren.
Within a few years their cattle had multiplied, leaving them in the enviable position of having excess manure. Enviable, because the Sabiikas knew about the biogas collection technology which has become popular in small agricultural and peri-urban settings, not only in Africa, but across the world.

Improved biodigester, Honduras. Courtesy: Heifer International

In late 2009 a biogas ‘digester’ was installed near their home by Heifer International and the Uganda Domestic Biogas Program (UDBP) partnership, and within a month they started collecting gas.
Prior to the use of biogas, Mrs. Sabiika said, cooking with firewood was “a nightmare” – particularly during rainy season. Women and children will traditionally spend long hours collecting firewood – contributing to the deforestation of habitat, and detracting from their ability to attend schools or get jobs. Cooking over a fire is also hazardous, because of the noxious smoke, and open fires prove dangerous to small children.

How it Works

Chinese biodigester. Courtesy: Heifer International

Dung is fed into a containment chamber – in Honduras it might be a heavy-duty plastic structure; in China, a domed concrete over brick repository – called a digester. In this oxygen-free environment bacteria breaks down the organic waste creating a mixture of gases, predominantly methane, which is combustible. The gas is captured and converted into energy, used for cooking, lighting and heat.
“I could not believe when I had the gas coming,” said Mr. Sabiika. “I immediately got a match box to test and to my surprise, the gas could cook and light.” The biogas, he added, cooked quickly and cleanly; and although customarily men in his culture do not cook, he bucked that tradition and made himself a cup of tea.

Taiwan biodigester. Courtesy: Heifer International

Biogas is beneficial for so many reasons. It improves the quality of life and economic condition for the families involved; eliminates harmful smoky wood and coal fires from their homes; and diverts methane gas from the environment. The process destroys germs that exist in the fecal matter, and helps reduce water pollution from runoff waste.
Added UDBP Engineer Kato Christopher, “Owing to the increasing energy demand and increased deforestation, this program is a timely action taken towards encouraging the general public to reduce the energy demand through efficient use of the existing energy sources.”
Another byproduct of the byproduct? An organic fertilizing slurry that helps families grow more vigorous crops.

Improved oven (ecologic). Courtesy: Heifer International

“I used to think the only thing cows produced was milk,” said Juan, a Honduran farmer who now hosts a bio digester. “My cow gives me milk, calves, it can give me meat, organic fertilizer and something I never imagined: fire for my stove!”
Switching from firewood to biogas has helped save trees and eliminate odor and pollution produced by smoky fires, he added. “Sometimes people aren’t thinking about the environment and they are wasting their resources and contaminating the environment. Bio digesters have really helped to save trees and help protect the environment.”


source: http://ecology.com/ecology-today/2011/08/11/biogas-digestors-improve-quality-of-life-while-protecting-the-environment/