This work presents a critical analysis for three models group of methanogen potential prediction. The first group allows determination of the methane productivity of substrates, through three models (BMPthCOD, BMPthAtC and BMPthOFC). The BMPthCOD is suitable for a first approximation calculation. BMPthAtC and BMPthOFC are more accurate; however, require a complex characterization of substrates. The second models group predicts the cumulative methane production using seven models. The analysis shows that the Artificial Neuron Network (ANN) is more accurate; moreover, it allows carrying out an optimization of the cumulative methane production. The third group of models is particularly involved in the determination of daily flow of methane by a biodigester. The Hashimoto model, which uses the operating parameters, has been identified as the most suitable.

	Key words: Biochemical methane potential (BMP), anaerobic digestion, kinetics, methane production, artificial neuron network (ANN), substrate.

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Theoretical models for prediction of methane production from anaerobic digestion: A critical review

The beneficial effects of biofuels as components of the worldwide energy supply are unquantifiable because they have versatile applications. However, an adequate understanding of the chemical properties of typical biomass is an integral aspect of maximizing the energy potentials because it is susceptible to biomass behavior during the conversion process, especially anaerobic digestion. Therefore, this study investigated the physicochemical characteristics of selected lignocellulose biomass, namely; cow dung, mango pulp, and Chromolaena odorata of Nigerian origin. The raw biomasses were characterized by proximate, calorific, ultimate, compositional, and microbial (for cow dung only) analyses using ASTM standards and equipment. Raw biomass characterization showed that cow dung, mango pulp, and Chromolaena odorata leaves recorded percentages; fixed carbon, volatile matter, and ash contents in addition to calorific values in the ranges of 6.22-7.25%, 5.02-7.79%, 1.14-1.91,% and 13.77-16.16 MJ/kg, respectively. The ultimate analysis of cow dung, mango pulp and Chromolaena odorata recorded carbon (43.08, 39.98, 41.69%); hydrogen (7.87, 6.74, 9.86%); nitrogen (1.53, 1.34, 1.51%); sulphur (0.46, 0.12, 0.25%) and oxygen (47.06, 51.82, 46.69%), respectively. Compositional analysis of the biomass gave percentages in the range of 7.47-11.37 for hemicellulose, 0.22-6.33 for lignin, and 3.71-12.03 for cellulose, while the microbial analysis of cow dung gave total bacteria counts of 5.78 × 108 and 3.93 × 105 cfu/g on wet and dry bases, respectively, which implied that it was rich in microbial colonies, evidently from the various species found, such as Escherichia coli, Staphylococcus aureus, Bacillus cereus, Pseudomonas aureginosa, Proteus morganii, and Micrococcus spp. In this regard, the physicochemical properties of selected biomass of Nigerian origin were established to conform with those of the literature and thus can be regarded as suitable feedstock for anaerobic digestion resulting in methane-rich biogas products. 

https://www.nature.com/articles/s41598-022-07061-2.pdf

Investigation of physicochemical characteristics of selected lignocellulose biomass

Optimization of biogas yield from anaerobic co-digestion of corn-chaff and cow dung digestate: RSM and python approach.

A cursory look is taken at the spectrum of research from pure basic, strategic basic, applied, experimental development or research and development (R and D) to endogenous research and development (ER and D). The existing strategies for disseminating research output identified within the Research Information Cycle included: Informal Communication (during seminars, workshops, symposia etc), Primary publications (journals, patents, reports), Secondary publications (abstracts, indexes, monographs) and Tertiary publications (books and treatise). Others were Exhibitions and Fairs, Extension Services and the Media (print and electronic). The compatibility, and need for ICT deployment at every node or link of the Research Information Cycle was demonstrated by comparing the capabilities of the orthodox (traditional) and virtual libraries in research information exchange. The major drawbacks or constraints to an efficient and timely dissemination of research output, particularly within the Nigerian research community, were identified to include: poor funding for research, high cost and limited publication channels, poor library facilities, dearth of ICT infrastructure/ICT human resources, age-long disconnect between the media and research institutes, weak patronage particularly of endogenous RandD by commerce and industry, among others. Some suggested interventions to mitigate the above constraints were: an evolution of new dynamics of funding research and innovation involving government-research community-industry partnerships, active promotion of local content policy by government to encourage the demand for, and supply of research information, deliberate capital infusion by all research stakeholders into developing ICT infrastructure and ICT human capacity. Other recommended interventions were subsidies for publishing research materials, phased replacement of orthodox (traditional) with virtual libraries, attitudinal change to imbibe reading culture by the public etc. A strong case was made for the emergence of a powerful National lobby or advocacy group, to re-awaken national consciousness on the compelling need for all to contribute to the means of boarding the `global research information train’. To do otherwise, it was argued, is to risk remaining essentially, a buying and selling nation.

Keywords: Research output; Dissemination platforms; Challenges and mitigation strategies; Nigeria.

Cattle dung biogas as a renewable energy source for rural laboratories.

Anaerobic digestion is a system that can have a high environmental impact through the use of different wastes to obtain biogas and its consequent use for the generation of renewable energy. The objective of this study was to implement a polyethylene biodigester, using polystyrene for thermal insulation in a dog kennel, using canine feces collected in the same place during a period of 5 months to obtain biogas and energy. The results indicated that biogas production started on day 30 and stopped during the winter period with low temperatures; therefore, from day 54 onwards, equine manure was added to continue producing biogas. Although biogas was obtained, the biodigester did not function optimally, due to the fact that the materials used in its construction did not provide efficient insulation from the low external temperatures; the low C/N ratio of the canine feces, which led to a reduction in the processing of the methanogenic bacteria; and the low amount of feces collected for use. In general, the use of a biodigester can provide a tool for the biological processing and management of organic waste, yielding a cumulative source of renewable energy and ensuring environmental safety.

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Biodigestion System Made of Polyethylene and Polystyrene Insulator for Dog Farm (on the Example of the Republic of Chile)

Investigations were conducted to compare gas produced from co-digestion of corncob, rice chaff, goat dung and dog dung with commercial gas. The study was carried out anaerobically at a temperature of 29.5 to 33°C (mesophilic condition) in a mini laboratory digester (bioreactor) fabricated using guage 16 metal sheets with 80-L capacity for a 90-day retention time. The shredded corn cob and rice chaff were mixed with water at ratio 4:1 (waste to water) and 3:1 (waste to water) respectively and mixed with goat and dog dungs at ratio 2:1 (waste to water). The control sample collected from a domestic cooking gas cylinder contained 56.12% CH2, 0.14% NH3, 0.22% CO, 0.23% H2S and 43.20% CO2. The result obtained for the biogas analysis shows that Sample E (75:25) contains 63.54% CH4, 0.93% NH3, 0.84% CO, 0.54% H2S, 34.12% CO2. The value recorded for sample E represented the highest value obtained among the samples. Also the gas composition shows a good substitute for commercial gas.

	Key words: Corn cob, rice chaff, goat dung, dog dung, biogas, commercial gas, bioreactor and digestates.

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Comparative study of commercial gas with biogas produced from co-digestion of corn cob, rice chaff, goat and dog dungs

The study is to investigate the viability of corncob and rice chaff co-digested with goat and dog dungs in the production of biogas and the PCR detection of the methanogenic bacteria involved. The study was carried out at mesophillic condition between (29.5 –33 0 C) in a mini laboratory digester fabricated using guage 16 metal sheets with 80L capacity for a 90 days retention time. Corn cob and rice chaff were shredded and mixed with water with ratio 4:1 and 3:1 (waste to water) respectively and mixed with goat and dog dungs with ratio 2:1 (waste to water) and digested anaerobically. The proximate analysis of all the substratesused were carried out and the result shows a C:N (carbon, nitrogen ratio) that is appropriate for the biogas production. The result shows a yield of 15L after 20days at temperature 31 0 C and pH 6.2, there was a drop in the yield and then an increase from the 40th day of digestion. The cumulative production was 37L at temperature 31 0 C and pH 5.9. The bacteria isolated from the samples includes; E. coli, Proteusspp, Klebsiellapneumoniae,Serratia. spp, Flavimonas spp. The result revealed that this combination of substrates can yield significantly biogas.

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D V Adegunloye

Papers

Comparative study of commercial gas with biogas produced from co-digestion of corn cob, rice chaff, goat and dog dungs

Study On the Biogas Yielding Potential of a Portable Bioreactor Using a Blend of Corn Cob and Rice Chaff Mixed With Goat and Dog Dungs