The utilization of biogas is common in the Mekong Delta and sustainable in animal husbandry as a supplement, to farm activities on a household-scale (up to about 20 pigs, for instance).
Acceptance & Attention
Using gas instead of other types of fuel is well accepted by local farmers because of its savings on fuel and the convenience of biogas compared with firewood or kerosene. However, in the Mekong delta, there is much less attention and attraction from the owners of larger scale animal farms to the utilisation of biogas and, in consequence, anaerobic treatments. Animal farms with a scale of 100-200 pigs and about 1000-5000 chickens become more and more common in Vietnam.
Waste treatment, especially with anaerobic technology, is needed to be given more attention in the operation of intensive and specialized farms, which cause more pollution than the micro scale. The biogas digester seems to be the most suitable solution to treat the waste from animal farms. However, in this small and medium scale, the amount of biogas produced is much higher than the domestic demand for cooking, lighting etc.
A large surplus of biogas is expected. Only when some economical ways to use this biogas can be introduced, farm owners will be willing to pay for anaerobic technology.
A new study showed, that:
- running engines with biogas can be technically and economically feasible and suitable for farms with 80 pigs or more.
- burning biogas for direct-heated driers can be feasible for farms with 120 pigs or more. Futural economical feasibility is expected.
- burning biogas for dryers with heat exchanger can be technically feasible for pig farms with 120 animals, but not economically.
The Benefits of Biogas Systems within Integrated Farming Systems
The original intensive farming model VAC integrates crops (V), fish (A) and pigs (C) into a symbiotic system that reduces the dependence on external inputs, while increasing productivity. However, the system does not provide a proper treatment of animal waste.
-> Integrated Farming Systems
The VACB farming model is, therefore, a much improved version of VAC. It yields more profit for the farm while improving the whole environment. In order to contribute to poverty alleviation, hunger eradication and ensure sustainable rural development, the Renewable Energy Center (REC) of Can Tho University in the Mekong Delta has established about 20 VACB models.
After three years complementation (1993-1996) the following conclusions have been achieved:
- To establish VACB system, the role of well trained pilot VACB owners, the extension workers and self-help group leaders should be to cooperate in a combined spirit in order to support the poor.
- The target group is to upgrade members in the self-help group, to become members of VAC groups and later owners of integrated farming systems, which include biogas system (B). This can increase the family income considerably, contribute to the provision of a renewable energy source, and provide fertilizer in the rural areas.
- Last but not least, the biogas system diminishes organic pollution in rivers and channels, which is of great importance in the Mekong River Delta.
- In order to reach this target, the assistance from the government, universities, and the local authorities to organize the farmers' self-help group, is the most important factor.