Biogas technology is developing quickly in Vietnam. However, research institutes mainly concentrate on completing the small-scale biogas digesters for farming households; therefore, by the end of 2012, the total number of constructed household biogas digesters in Vietnam has reached nearly 1 million out of the potential 6 million households. In the meanwhile, medium-scale biogas digesters have not gained proper attention.
Within the framework of the project “Developing the market for medium-scale plug-flow biogas digesters in Vietnam” funded by the Energy and Environment Partnership with the Mekong Region (EEP Mekong), Institute of Energy has completed the design and piloted a medium-scale biogas digester – the plug-flow digester type. This digester is designed on the operation principles of a fixed-cover digester with regular flow. The design is programmed in excel software, calculating and producing the digester design for a farm with over 250 to 3,000 pig heads. Biogas production efficiency is 0.3 – 0.36m3 gas/m3 digested sludge, biogas processing efficiency is 90% and the investment rate for 1m3 of the digester is 1-1.2 million VND. The digester can provide gas for power generation, heating, cooking and lighting; and the payback period is 3-4 years.