Optimization of biogas production from some agrowastes in a batch system bioreactor
| dc.contributor.author | Nwaneri, Chioma Blessing | |
| dc.date.accessioned | 2026-03-26T12:47:37Z | |
| dc.date.available | 2026-03-26T12:47:37Z | |
| dc.date.issued | 2023-12 | |
| dc.description | This thesis is for the award of Doctor of Philosophy (PhD.) Degree in Environmental Microbiology | |
| dc.description.abstract | This study was carried out to co-digest and optimize biogas production from some agrowastes in a batch system bioreactor. Six substrates; Palm oil mill effluent (POME), Pig dung, Cow dung, Poultry manure, Cassava peels, and Cabbage waste were used in the investigation. The proximate analysis of each substrate and the microbiological analysis of the co-digested subsrates were obtained. The substrates were anaerobically digested as single substrate and codigested with each other to improve the nutritional composition and biodegradability. Laboratory scale 10L capacity bioreactors were used to carry out the batch system anaerobic digestion of the different substrates for substrate ratios of 1:1, 2:1, 3:1, pH range of 6.8-8.0 and a hydraulic retention time of 45days. Then Box Behnken’s design of response surface methodology of three factors; substrate ratio, pH, and hydraulic retention time at three levels; 1:1, 2:1, 3:1(substrate ratios), 5, 7, 9 (pH) and 15days, 30days and 45days (hydraulic retention time) were used in the optimization, considering the substrate with the highest biogas yield.Sodium hydroxide (NaOH) and hydrochloric acid (HCl) were used for adjusting the pH values to the required range. Compositional gas analysis of biogas produced was carried out using Gas Chromatography. The proximate analysis of the substrates showed that the C:N ratios of POME, pig dung, cow dung, poultry manure, cassava peels and cabbage waste were 10.13:1, 5.84:1, 17.50:1, 14.24:1, 46:1 and 16.90:1 respectively. It was also observed that none of the substrates had an optimium C: N ratio hence there was need for co-digestion of the substrates to improve biogas yield. The result also showed that co-digestion of cassava peels with cow dung had the highest biogas yield, flamed on the second day with bright blue flame and had the highest percentage methane content of 78.05%. The results showed the presence of these bacterial isolates; Escherichia coli, Enterobacter sp, Salmonella sp, Shigella sp, Bacillus sp, Pseudomonas sp, Staphylococcus sp, Micrococcus sp and fungal isolates were Saccharomyces sp, Aspergillus sp, Rhizopus sp, Penicillium sp, Geotrichum sp. The optimization result showed that the substrate ratio of 3:1, pH 7 and 15days hydraulic retention time had the highest biogas yield, highest methane content of 79.143% and flamed on the second day of the anaerobic digestion. Statistical analysis of the results showed significant difference (p ≤ 0.05) in biogas production in all the treatments. Further anaerobic digestion of cassava peels with cow dung using the predicted values from the computer aided Box Behnken design response surface methodology analysis showed the same trend with the experimental data. In terms of sustainable biogas production, the outstanding result showed by CP/CD 3:1 at pH 7 proves that the test parameter can be adopted for domestic biogas production. | |
| dc.identifier.citation | Nwaneri, C. B. (2023). Optimization of biogas production from some agrowastes in a batch system bioreactor [Unpublished DoctoralThesis]. Federal University of Technology, Owerri, Nigeria | |
| dc.identifier.uri | https://repository.futo.edu.ng/handle/20.500.14562/2500 | |
| dc.language.iso | en | |
| dc.publisher | Federal University of Technology, Owerri | |
| dc.rights | Attribution-NonCommercial-ShareAlike 4.0 International | en |
| dc.rights.uri | http://creativecommons.org/licenses/by-nc-sa/4.0/ | |
| dc.subject | Anaerobic digestion | |
| dc.subject | agrowastes | |
| dc.subject | optimization | |
| dc.subject | gas chromatography | |
| dc.subject | biogas | |
| dc.subject | Department of Microbiology | |
| dc.subject | methane content | |
| dc.title | Optimization of biogas production from some agrowastes in a batch system bioreactor | |
| dc.type | Doctoral Thesis |