Biodigester Systems

Context and Background

The use of chemical fertilizers to increase crop production and the use of firewood as the main source of household energy have contributed significantly to many rural Guatemalan households being trapped in a vicious circle of poverty and environmental degradation.  As households spend more money on fertilizers and firewood to satisfy basic food and energy needs, they create a cycle of dependence which makes it impossible for them to escape from a bare subsistence economy.

Biodigesters, by providing high quality organic fertilizer and gas for cooking, reduce consumption of chemical fertilizers and firewood.  A biodigester is an anaerobic fermentation tank. Organic waste such as manure and food scraps, are mixed with water and poured into the tank. Anaerobic bacteria generate biogas, a combustible mix of methane and carbon dioxide. The fermentation process destroys pathogens, resulting in safe nutrient rich effluent that can be used as an organic fertilizer.

With the use of a biodigester in a rural household, these two vicious circles are turned into positive circles of environmental sustainability and increased economic stability. There are over 25 million family-scale biodigesters in the world, principally in India and China, and they have great potential for Guatemala. Our market research has shown that at least one million Guatemalans live in a household with the necessary conditions for successfully operating a biodigester.

Alterna’s Approach

We are working hard to adapt the basic technology for the conditions on the ground in Guatemala develop the most economic, easy to use, and easy to install biodigester system in Central America.  We are working closely with communities to refine our technology and adapt it to their needs, and with key private sector players and financial intermediaries to turn community requirements into product and service reality.

Benefits of Using a Biodigester

• Biogas cooking fuel displaces the need to buy propane and firewood, saving money and insulating families from rising energy costs.
• Animal manure can be disposed of safely, reducing smells, flies, and the spread of disease.
• Biodigester effluent is a powerful organic fertilizer reducing the need to purchase and apply chemical fertilizers, saving money and decreasing chemical runoff.

 Challenges

• Most people will not significantly change their daily routine to use a biodigester.  The biodigester must be as easy-to-use and inconspicuous as possible.
• The biodigester represents a significant upfront investment.  Creative financing options are a must.
• Training, technical assistance, and followup.  A biodigester isn’t difficult to take care of once someone understands it, but extra effort must be made to make sure the understanding is sufficient.

Status: Business Launch planned for 2012!

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