Virtually all countries, especially the developing nations, are being confronted with the twin
problems of waste management and energy deficit. This development has led to the search for
renewable energy sources. Although pig dung, water hyacinth and maize cob have been
identified as good feedstocks for biogas production, studies utilising their mixtures have not been
fully explored. This study was therefore designed to evaluate the biogas yield and microbial
species from mixtures of biomass feedstocks.
The feedstocks utilised for this study comprised Pig Dung (PD), Water Hyacinth (WH), and
Maize Cob (MC). The PD and WH were sourced from University of Ibadan Teaching and
Research Farm while MC was sourced from refuse bins in Oje Market. Six feedstock groups
were selected namely PD, WH, MC, PD:MC (PM), PD:WH (PW), and PD:MC:WH (PMW).
Each mixture was made in equal proportion on dry weight basis. A simple biogas digester was
fabricated from a 10-litre plastic keg for feedstock biodegradation. Each feedstock sample to be
digested was prepared by mixing 0.75 kg dry feedstock with 8.25 litres of water in the ratio of
1:11 (w/v) to form slurry. The slurry was fed into the corresponding digester, and kept for 35
days for anaerobic digestion while samples of the effluent were taken at seven days interval for
five weeks for laboratory analyses. Parameters including temperature, pH, carbon, nitrogen,
carbon to nitrogen (C-N) ratio, potassium, phosphorus, and microbial identification
characteristics were determined using standard methods. Gas generated was estimated based on
Archimedes’ Principle. Data were analyzed using descriptive statistics and ANOVA at p ˂ 0.05.
Temperature and pH of all slurries ranged from 25.75±0.4oC to 28.75±0.4oC and 5.80±0.0 to
7.85±0.1 respectively. There was a significant difference in percentage nitrogen, phosphorus and
potassium of the various slurries. Mean C-N ratio of the various slurries decreased from day 0 to
day 35 as follows: 20.05±2.1 to 16.27±1.1, 23.28±0.1 to 12.95±1.2, 97.54±3.3 to 47.70±1.3,
57.27±0.2 to 28.34±2.1, 28.52±4.2 to 24.19±2.0 and 49.86±2.9 to 37.24±2.4 for PD, WH, MC,
PM, PW, and PWM respectively. Predominant organisms identified at day 35 were:
Methanobacterium, Enterobacter and Aspergillus spp. The anaerobic, coliform and fungal
counts ranged from 6.80×102
cfu/g, and 9.1×103
cfu/g respectively throughout the duration of the study. The highest anaerobic count
cfu/g) was recorded in PW on day 28. Peak biogas production was observed
on day 23 for PD (987.50±3.5mL); day 24 for PW (1095.00±7.1mL), and PM (732.50±17.7mL);
day 25 for MC (560.00±7.1mL), day 26 for WH (635.00±7.1mL) and PMW (662.50±10.6mL).
Group PW had the highest biogas yield of 6067.00±38.2mL for the entire duration of the study.
There was a significant difference between the mean biogas yields of the various feedstock
Co-digestion of pig dung with water hyacinth had the highest number of anaerobes and biogas
yield as compared to single feedstocks. Therefore, the use of multi-biomass feedstocks for biogas
production as a source of alternative energy production should be fully optimised.
CDR, C (2021). Evaluation of Biogas Yield and Microbial Species from Multi-Biomass Feedstocks. Afribary.com: Retrieved April 15, 2021, from https://afribary.com/works/evaluation-of-biogas-yield-and-microbial-species-from-multi-biomass-feedstocks
Coalition, CDR. "Evaluation of Biogas Yield and Microbial Species from Multi-Biomass Feedstocks" Afribary.com. Afribary.com, 03 Apr. 2021, https://afribary.com/works/evaluation-of-biogas-yield-and-microbial-species-from-multi-biomass-feedstocks . Accessed 15 Apr. 2021.
Coalition, CDR. "Evaluation of Biogas Yield and Microbial Species from Multi-Biomass Feedstocks". Afribary.com, Afribary.com, 03 Apr. 2021. Web. 15 Apr. 2021. < https://afribary.com/works/evaluation-of-biogas-yield-and-microbial-species-from-multi-biomass-feedstocks >.
Coalition, CDR. "Evaluation of Biogas Yield and Microbial Species from Multi-Biomass Feedstocks" Afribary.com (2021). Accessed April 15, 2021. https://afribary.com/works/evaluation-of-biogas-yield-and-microbial-species-from-multi-biomass-feedstocks