2014 ASABE and CSBE/SCGAB Annual International Meeting
Plug flow biodigesters are popular in developing countries due to their low cost and ability to adapt to microclimates to produce biogas for cooking. These biodigesters are primarily composed of a polyethylene bag and PVC, and, typically, cattle or hog manure is used as both the organic and microbe source for gas production. The biogas is piped to a gas stove to be used for cooking. The digesters are intended to replace traditional wood burning stoves prevalent in developing countries, which are attributed to over two million deaths per year. However, due to pressure limitations due to the plastic bag, only 30 to 45 minutes of gas is available at a time, so diet staples, such as rice and beans, cannot be cooked. A low cost, effective solution to utilize more of the biogas was developed and tested on an existing plug flow biodigester in Nicaragua using PVC and plastic water bottles, which are widely available in the country. With the new system, beans were successfully cooked in less time using less water than the traditional wood stove. It also allowed for approximately four hours of gas to be used at one time. The system is cost effective because it would only add 8% to the overall price of the biodigester if the system were installed at the same time as the biodigester was installed and 16% if it was sold as an aftermarket add-on. In the long term, this system would save money for the user because they would be able to spend more time working instead of collecting firewood.
American Society of Agricultural and Biological Engineers
Geiger, Linda R. and Regan, Kelsey B., "Designing a Low Cost Biogas Pressurizing System in Nicaragua" (2014). Agricultural and Biosystems Engineering Conference Proceedings and Presentations. 381.