Low-Cost Polyethylene Tube Digesters in Bolivia

Brief description of the technology

Low-Cost Polyethylen Tube Digesters at the present moment have a cost between 93,- € and 148,- €. To operate a digester, the producer has to charge it day to day with 20 kg of cow dung (or other animal dung), mixed with 60 liters of water. Once the digester starts its operation (between 30 to 60 days), produces daily around 4 and 5 hours of biogas, for cooking or other applications like use of gas lamps. Furthermore the digester provides daily 80 liters of ecologic fertilizer which helps to increase the production of agriculture. The digester system has a pressure between 15 - 20 cm of water column.

The household tube digesters possess a triple win situation:

• In the economic sense; the producer does not have to buy liquid gas, firewood or chemical fertilizer.
• In the health sense; the family is not exposed to health treats by exhaust gas by cooking.
• In the ecological sense; the environment threat is reduced due to the decrease in the use of chemical fertilizers and organic waste exposures. Furthermore, it also helps with reduction of the deforestation by consumption of firewood.

Objective of the project

Convert household tube digesters into an additional tool within the productive uses of families in the rural areas of Bolivia, in such a manner that the knowledge will be transferred to local technicians.

• In the short term: Train more local technicians in installation and management of household bio digester projects in Bolivia, so as to disseminate the technology between rural families.
• In the medium term: Spread the tube digester technology at a national wide level, so that families may learn about the method and from this, under their own criteria, decide if they will incorporate such technology into their productive system.
  
• In the long term: Democratize the technology in such a manner that communities, producer associations, municipalities, etc. may develop and manage their own tube digester projects without external assistance or technological subsidies.

Support provided by GTZ / EnDev Bolivia

In order to reach the objective, GTZ provides the following support: Technical advice for tube digester projects. Technical and theoretical training to groups of professionals and institutions, throughout workshops. Technical training for local technicians and producer associations throughout intensive workshops (3 days). Subvention between 20 - 25 % in material costs for the tube digesters. The subvention is open to be complemented by other donors, with the condition that the contrapart of the family will be at least 50 % of the material costs. Coordination and broadcast of the information of tube digesters, as a mean of contact with institutions interested in biogas in Bolivia.

Certificated local technicians in Carabuco / Bolivia Source: GTZ / EnDev Bolivia