Design and Testing of a Portable Biogas Digester for Rural Households

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Rural households lack access to clean cooking fuel and often rely on firewood. This project designed a portable biogas digester for rural households. The digester comprised a flexible PVC bag (2 m3 capacity), inlet and outlet pipes, gas storage bag, and simple burner. Design criteria included portability, low cost, and ease of operation. Feeding with kitchen waste and cow dung produced 0.8-1.2 m3 biogas daily, sufficient for 3-4 hours cooking. Gas composition averaged 58% methane and 38% carbon dioxide. The system reached steady production within 15 days of startup. Material cost was N45,000 with expected lifespan of 5 years. The digester can replace firewood, reducing indoor air pollution and deforestation while providing organic fertilizer from digestate.