Production of Biofertilizer and Biomethane from Co-Digestion of Lignocellulosic and Keratinolytic Substrates

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Production of Biofertilizer and Biomethane from Co-Digestion of Lignocellulosic and Keratinolytic Substrates

Aniaku, V. O.1 and Aniokete, T. C.2
Department of Applied Microbiology and Brewing, Enugu State University of Science and Technology1
Department of Chemical Engineering, Enugu State University of Science and Technology2

ABSTRACT

Environmental pollution from organic wastes such as poultry feathers and rice husks is on the increase in Nigeria with their attendant environmental impacts and health implications. The need to harness the economic potentials of essential wastes from the agro-allied sectors under waste to wealth initiative in Nigeria cannot be overemphasized. Production of biofertilizer and biogas from the anaerobic digestion of poultry feather and rice husk using 5% cow dung as source of microbial consortia was investigated. The constituent microbial consortia used for anaerobic digestion were identified molecularly as Bacillus, Cellulomonas, Pseudomonas, Methanosarcina and Methanobrevibacter species based on their 16S rRNA gene sequences. The result of the proximate analysis of rice husk showed that the volatile solid content, carbon, nitrogen, ash and carbon-nitrogen ratio (C/N) were 68.50%, 42.50%, 0.840% 1.92% and 51:1 respectively while poultry feather had volatile solids and carbon-nitrogen ratio of 96.50% and 4:1 respectively. The feed stocks were hydrothermally treated with steam under pressure, dried at 80oC and milled to a size of 10 µm prior to anaerobic digestion. Anaerobic digestion of the rice husk powder and poultry feather powder at 1:1 ratio under mesophilic condition (35-40oC) at feed stock water ratio of 1:7 lasted for 38 days using four different consortia. The methane yield from rice husk and poultry feather as single substrate were 18.50cm3/g and 14.67cm3/g respectively while the methane yield as combined substrate (1:1) was 30.72cm3/g. The result of compositional analysis of biogas stream obtained by infrared-absorption technique showed that methane and carbon dioxide had average value of 72% and 27% using consortium 4 followed by consortium 3, 2 and 1. The result of digestate (spent slurry) analysis after anaerobic digestion showed that the digestate was rich in micronutrients essentially, Phosphorus (0.16g/l), Nitrogen (2.52 g/l), Calcium (0.93 g/l), Potassium (0.37 g/l) and Magnesium 0.78 g/l). The liquid digestate had pH of 7.30 and total solids content of 16.50%. The use of digestate as fertilizer for enriching the soil for agricultural purposes should be encouraged as the digestates are rich in bioactive agents and mineral elements which help in conditioning the soil. The analysis of variance of the results on methane yield shows that biomethane production was significantly (P≤ 0.05) dependent on the bacterial consortia, substrate constitution and their pair wise interactions.
KeywordsBiofertilizer and Biomethane; Poultry Feather; Anaerobic Digestion; Production of Biofertilizer; Biomethane Micronutrients
CitationAniaku, V. O. & Anoikete, T. C. (2023). Production of Biofertilizer and Biomethane from Co-Digestion of Lignocellulosic and Keratinolytic Substrates. American Journal of Applied Sciences and Engineering, 4(2) 1-15.  https://doi.org/10.5281/zenodo.8248356
Full AccessFULL PDF | DOI: 10.5281/zenodo.8248356
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