Comparative Biogas Generation from Cow Rumen Waste and Human Fecal Slurry at Different Retention Times
نویسندگان
1 Africa Centre of Excellence in Future Energies and Electrochemical systems (ACE-FUELS), Federal University of Technology, Owerri, Nigeria.
2 Africa Centre of Excellence in Future Energies and Electrochemical systems (ACE-FUELS), Federal University of Technology, Owerri, Nigeria.
3 Africa Centre of Excellence in Future Energies and Electrochemical systems (ACE-FUELS), Federal University of Technology, Owerri, Nigeria.
4 Africa Centre of Excellence in Future Energies and Electrochemical systems (ACE-FUELS), Federal University of Technology, Owerri, Nigeria.
5 Africa Centre of Excellence in Future Energies and Electrochemical systems (ACE-FUELS), Federal University of Technology, Owerri, Nigeria.
6 Department of Microbiology, School of Biological Sciences, Federal University of Technology, Owerri, Nigeria.
doi
10.30501/jree.2025.483367.2129چکیده
The generation of biogas from cow rumen waste and human fecal slurry at different retention times was investigated. Microbial growth, pH, and the volume of biogas produced from the two substrates were monitored over a 60-day retention period. Temperatures were maintained within the mesophilic range. Both microbiological and physicochemical analyses were conducted. The results revealed the presence of Citrobacter sp., Moellerella sp., Providencia sp., Shimwellia sp., Micrococcus sp., Bacillus sp., Proteus sp., Paenibacillus sp., Budvicia sp., Solibacillus sp., Photobacterium sp., and Breuundimonas sp. The pH values steadily decreased alongside the total viable count, leading to a decline in biogas production from both substrates. Peak biogas volumes of 251.226 cm3 on the 45th day and 226.103 cm3 on the 48th day were recorded for cow rumen waste and human fecal slurry, respectively. In cow rumen waste, the pH decreased from 8.1 to 4.61, indicating a shift from slightly alkaline to acidic. In human fecal slurry, the pH dropped from 8.1 to 6.80, indicating a shift from slightly alkaline to nearly neutral. GC-MS analysis after the 60-day retention period showed that biogas from cow rumen waste comprised 50.39% methane, 19.21% carbon dioxide, 6.52% hydrogen sulphide and 5.33% ammonia. In contrast, biogas from human fecal slurry contained 57.99% methane, 17.12% carbon dioxide, 1.80% hydrogen sulphide and no detectable ammonia. The absence of ammonia in the human fecal slurry was attributed to its high moisture content of 99.39%, as indicated by the results of the proximate analysis. It can therefore be concluded that these waste products, which are typically environmental nuisances, can be effectively managed through conversion into biogas.
