Global Journal of Engineering and Technology Research (GJETR)

Design, Fabrication and Evaluation of a Mini-Biogas Plant with Automatic Pressure Relief Control for Power Generation

Ayomide, Alase David, David O, Prof. Aborisade

27 July 2026 · Vol. 2, Issue 7, pp. 302-311

DOI: 10.65150/EP-gjetr/V2E7/2026-08

Abstract

The growing demand for decentralised, sustainable power in Nigeria, combined with the poor management of organic waste in rural and peri-urban areas, motivates the development of small-scale, waste-to-energy technologies. This paper reports the design, fabrication and performance evaluation of a mini-biogas plant that converts cow dung and kitchen waste into electricity through anaerobic digestion, gas conditioning and a modified petrol generator, while a fully passive, electronics-free automatic pressure relief system based on an adjustable water seal protects the digester from over-pressurisation. The 1000 L high-density polyethylene (HDPE) digester was filled with 70% cow dung and 30% kitchen waste in the ratio of 1:1 of dung to water and kept under observation for 5 weeks of retention time.The pH of digester was maintained in the desired range of 6.8 to 7.5 from Week 2 onwards whereas the average digestion temperature ranged from 28.1 °C to 30.8 °C. Average biogas production was 0.92 m³/day (design target 0.5-1.5 m³/day), with a peak of 1.18 m³/day. Gas conditioning raised methane content from 58.4% in the raw biogas to 67.2% after CO₂ scrubbing, within the 60-70% target band. The water-seal pressure relief system activated within 3-4% of its calculated set point at all three tested submerged depths (8, 10 and 12 cm) and re-sealed within 4-6 seconds, confirming that safe, automatic pressure regulation can be achieved without sensors, controllers or external power. These results demonstrate that a low-cost, locally fabricated mini-biogas system with a passive safety mechanism is a technically viable route to decentralised electricity generation and organic-waste management in resource-limited settings.

Keywords: Biogas, Anaerobic Digestion, Mini Biogas Plant, Pressure Relief System, Power Generation.

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Ayomide, Alase David, David O, & Prof. Aborisade (2026). Design, Fabrication and Evaluation of a Mini-Biogas Plant with Automatic Pressure Relief Control for Power Generation. Global Journal of Engineering and Technology Research, 2(7), 302-311. https://doi.org/10.65150/EP-gjetr/V2E7/2026-08

@article{Ayomide2026,
  title   = {Design, Fabrication and Evaluation of a Mini-Biogas Plant with Automatic Pressure Relief Control for Power Generation},
  author  = {Ayomide and Alase David and David O and Prof. Aborisade},
  journal = {Global Journal of Engineering and Technology Research},
  year    = {2026},
  volume  = {2},
  number  = {7},
  pages   = {302-311},
  doi     = {10.65150/EP-gjetr/V2E7/2026-08},
  url     = {https://doi.org/10.65150/EP-gjetr/V2E7/2026-08}
}

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