Browsing by Author "Matofari, Joseph"

Now showing 1 - 2 of 2
  • Publication
    Publication
    Effect of Total Solids on Biogas Production in a Fixed Dome Laboratory Digester under Mesophilic Temperature
    (Annals of Advanced Agricultural Sciences, 2020-05) Barasa, Henry; Nyaanga, David; Njue, Musa; Matofari, Joseph
    An investigation on the effect of total solids on biogas production was done using a laboratory scale batch reactor of 0.15 m3 capacity. The feedstock was dung from dairy cows managed under a free-range system. Experiments were done on a substrate having total solids of 6%, 7%, 8%, 9%, and 10% at a constant temperature of 35°C; and the mean biogas production was 0.249, 0.304, 0.487, 0.287, and 0.244 m3 of biogas per m3 of digester volume per day (m3/m3d), respectively. It was concluded that the highest average biogas production of 0.487 m3/m3d is attained at total solids of 8%.
  • Publication
    Publication
    Optimization of Biogas Production in a Batch Laboratory Digester Using Total Solids, Substrate Retention Time, and Mesophilic Temperature
    (International Journal of Power and Energy Research, 2020-07) Barasa, Henry; Nyaanga, David; Njue, Musa; Matofari, Joseph
    Optimization was done by investigating the interaction effects of total solids, mesophilic temperature, and substrate retention time on biogas production in a batch biodigester. The volume of the biodigester was 0.15m3. Central composite design of Response Surface Methodology was used to design the experiment. Total solid levels were varied from 6.31% to 9.68%, temperature was from 26.59°C to 43.41°C, and substrate retention time was from 9.95 to 20.04 days. Analysis of results was done using Design Expert software statistical package (version 10.0.0.3). It gave a coefficient of determination of 0.9665 which indicated a high correlation between the variables. All the variables had a significant effect. The highest biogas production rate of 75.41litres/day (or 0.50 m3 of biogas per m3 of digester volume per day, m3/m3d) was achieved at a level of 8% total solids, a temperature of 43.41°C, and a substrate retention time of 15 days.