As part of Earth Solutions on-going interest in green energy technology, we are focusing on an alternative energy source more affordable and less reliant on weather conditions than wind and solar powered sources: Anaerobic Biogas (methane) Digesters.

Biogas - an affordable alternative in the energy landscape

In recent history we have come to realize the effects on the planet due to inefficient usage of natural resources. Costs of carbon based fuels are rising, incurring financial hardships in many poorer areas of the world. Alternative energy options have been developed to counteract global warming effects. Solar cookers are one such option but are limited to only sunny days. An alternative energy apparatus is the anaerobic biogas digester.

What is an anaerobic biogas (methane) digester?

The anaerobic biogas digester is an apparatus formed by a double polyethylene bag, an exit valve and safety valve. Inside the bag excrements are fermented, giving as a result the production of a natural gas called biogas. This biogas can be used to heat and cook food, to create light, to heat farm animals, and generally, as an extra energy source. The fermented excrements that exit the biogas (methane) digester can be used as an organic fertilizer. In the production of biogas, you can use manure from cows, pigs, horses, goats, or even human feces. Installing a homemade anaerobic biogas (methane) digester is not very costly. Nevertheless, you will have to invest at least $120 in the cost of materials and installation. The amount of materials is directly related to the size of the anaerobic methane digester, whose length can vary from 5 meters to 50 meters.

In order to install a methane digester with 13 meters in length, you should get:

• 34 meters of 8-caliber transparent tubular polyethylene plastic with 4 meters of circumference

• 8 plastic 10-liter buckets

• 2 meters of a 1 1/4-inch plastic transparent hose

• A PVC "T" 1" thick

• A male PVC adapter, 1"

• A female PVC adapter, 1"

• 2 PVC elbows (90°), 1"

• 1 meter of PVC tubing, 1"

• A PVC plug to fit 1" PVC tubing

• Two rigid plastic washers with a hole in the center equal to 1"

• A two-liter bottle of soda or other equivalent container

• 3 car tire inner tubes, cut into two pieces equal in shape and size to the plastic washer, and the rest to set aside as tying materials are needed later in construction

• 8 empty fertilizer sacks

• A 1/2" metal tube

• A used garden hose

• A tube of PVC cement

Case Study/ Success Story

In many parts of the world energy is not only costly but also difficult to receive. The cost of carbon fuel had reached $15 per tank of gas in Santa Fe, Costa Rica, a price native families simply weren't able to afford. For a short period fire wood was used as primary source for cooking and heating. Utilizing an open fire in their homes, however, ended up producing more of a health hazard and environmental decline rather than providing safe and sustainable energy. A group of Costa Rican women took initiative to find a solution for the looming energy supply shortage in their community. In 2006, the UN Women's Group in Vienna provided aid in form of donations and along with the technical assistance of the Agriculture ministry office in Guatuso, the town of Santa Fe, Costa Rica, was able to build 16 bio-digesters. Bio-digesters provide an excellent and affordable energy source. The apparatus not only took care of the environmental and health threat from the burning of the firewood but simultaneously solved the problem of animal waste for the dairy producing town. The group of women continues to help other communities in their area to use bio-digesters as a viable energy resource.