Addressing problems at small-scale biogas plants: a case study from central Vietnam

The anaerobic digestion process is an important technology in improving the environment because it solves organic waste management problems and simultaneously produces both biogas and fertiliser. The use of biogas plants has been spreading in many developing countries, bringing various operational problems with their widening use. This study attempts to identify the problems with this technology at the level of owners of biogas plants (n = 141) and local facilitators (n = 9) in central Vietnam. A survey was conducted from July to September 2012. The methods of data collection included focus group discussions, semi-structured personal interviews and a questionnaire survey. The survey revealed that 29% of biogas plant owners have experienced at least one problem with this technology. The most frequently encountered problem is linked to leakages from reactors leading to undesired CH4 emissions, which sometimes stopped the biogas plants from functioning. Other problems concern the failure of biogas cookers to properly function with solid digestate incrustation floating in the main tank, resulting in decreased biogas production. The respondents call for better-trained builders and facilitators, who are often unable to solve difficulties encountered with BGPs. The importance of a working information flow between actors is demonstrated. The study also involves the calculation of the payback period of biogas plants. The findings show a linear relationship between the payback period and biogas plant-owners' satisfaction with biogas technology, biogas production and the biogas programme. In addition, the study recommends improvements in the skills of facilitators because they have a direct impact on the quality of training of BGP owners and builders. In conclusion, this study provided an innovative problem analysis of biogas technology along with appropriate recommendations. It demonstrated the need for further research on the eradication of problems associated with biogas technology.