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oai:repository.unam.edu.na:11070/42762026-07-04T22:01:18Zcom_11070_3408com_11070_3311com_11070_3304col_11070_642

Chiguvare, Zivayi Tomas, Pineas Panduleni 2026-07-02T09:23:04Z 2026-07-02T09:23:04Z 2025 http://hdl.handle.net/11070/4276 A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Science in Renewable energy The growing demand for sustainable and affordable energy solutions in rural areas has led to increased interest in biogas technology, particularly in developing regions. This thesis presents the design and evaluation of a low-cost biogas digester for the Neudamm Campus of the University of Namibia. The study adresses the campus's energy cost and the underutilisation of livestock manure as a renewable energy resource. A 100 L digester, constructed from locally available materials, was fed with a cow manure-water slurry and operated over a 60-day period. Key operational parameters included an estimated 30-day hydraulic retention time, with pressure monitored three times daily in the first week, twice daily from Days 8–21, and once daily thereafter.. The digester achieved an average daily biogas yield of 0.95 L, equivalent to 7.61 MJ (2.11 kWh). Based on manure availability at Neudamm (22.2 tonnes/day), the system could theoretically produce 318.76 L/day of biogas. This represents a payback period of 2.5 years and an estimated 594% return on investment over a 10-year lifespan. The gas produced was sufficient to substitute part of the campus’s electricity demand for cooking and water heating, demonstrating both economic and environmental benefits, including reduced greenhouse gas emissions and nutrient-rich slurry for fertilizer. The study acknowledges limitations such as short monitoring duration, reliance on pressure as the sole gas measurement, and minor leakage issues. ii Despite these constraints, the study demonstrates the feasibility of low-cost, small scale digesters in Namibia and provides a replicable model for rural settings. The findings contribute to renewable energy knowledge in Southern Africa and highlight practical opportunities for integrating biogas into campus and farm operations en University of Namibia Biogas Renewable energy Sustainability Namibia University of Namibia Viability of substitution of electricity with biogas for thermal uses at Neudamm campus of the University of Namibia Thesisopen.access