This review is a summary of different aspects of the design and operation of small-scale, household, biogas digesters. It covers different digester designs and materials used for construction, important operating parameters such as pH, temperature, substrate, and loading rate, applications of the biogas, the government policies concerning the use of household digesters, and the social and environmental effects of the digesters. Biogas is a value-added product of anaerobic digestion of organic compounds. Biogas production depends on different factors including: pH, temperature, substrate, loading rate, hydraulic retention time (HRT), C/N ratio, and mixing. Household digesters are cheap, easy to handle, and reduce the amount of organic household waste. The size of these digesters varies between 1 and 150 m 3 . The common designs include fixed dome, floating drum, and plug flow type. Biogas and fertilizer obtained at the end of anaerobic digestion could be used for cooking, lighting, and electricity.

https://www.mdpi.com/1996-1073/5/8/2911/pdf

Household Biogas Digesters—A Review

Biomethanation of banana peel and pineapple waste.

This reviews aims to provide an insight and update of the state of biogas technology research in some selected sub-Saharan African countries in peer reviewed literature. This paper also aims to highlight the sub-Saharan countries’ strengths and weaknesses in biogas research and development capacity. An attempt is made to pinpoint future research in critically reviewing the biogas technology research. The methane-producing potential of various agriculturally sourced feedstocks has been researched, as has the advantages of co-digestion to improve carbon-to-nitrogen ratios and the use of pretreatment to improve the hydrolysis rates. Some optimisation techniques associated with anaerobic digestion including basic design considerations of single or two-stage systems, pretreatment, co-digestion, environmental conditions within the reactor such as temperature, pH, buffering capacity have been attempted in some of the researches in Nigeria, Tanzania, and Zimbabwe. However, there appears to be little research in biogas technology in many sub-Saharan African countries in internationally peer reviewed literature. Biogas production from large quantities of agricultural residues, animal wastes, municipal and industrial wastes (water) appears to have potential as an alternative renewable energy for many African countries if relevant and appropriate research is carried out to adopt the biogas technology to the local conditions in African countries. African scientists are urged to carry out research in biogas technology to locally demonstrate the feasibility, application, and adaptation of this technology and help improve the quality of energy supply in their respective countries.

/pdf/biogas-technology-research-in-selected-sub-saharan-african-5bpec2xth8.pdf

Biogas technology research in selected sub-Saharan African countries – A review

Waste from the food processing industry (e.g. juice production) is produced in large quantities worldwide and contains high levels of lignocellulose. To some extent, value-added products are extracted from this waste, but the majority of the waste is currently unutilised and discarded. Energy generation from this waste has been investigated in the form of production of biogas, hydrogen and bioethanol. Efficient bioethanol production requires the enzymatic hydrolysis of the total polysaccharides within this waste into monomer sugars for further fermentation into ethanol. Factors limiting this process are the complexity of the lignocellulose, its recalcitrance and insolubility and the number of enzymes required to degrade it. Obtaining complete enzymatic hydrolysis of these substrates requires an understanding of the composition of the polysaccharides and their associations within the overall substrate. This will allow appropriate selection of enzymes. It has also been established from work on other lignocellulose substrates that the associations between polysaccharides pose an obstacle to their hydrolysis and cooperative enzyme interaction is required to overcome these obstacles. With respect to the enzymatic hydrolysis of food waste, the knowledge gaps have been identified as: (1) accurate knowledge of the polysaccharide composition and structures; (2) knowledge about the associations that exist between different polysaccharides; (3) and the enzymes required for hydrolysis of the overall polysaccharide component and the synergistic interactions between these enzymes. This review investigates these aspects in literature, exposing the gaps in knowledge, while making proposals for future work that could assist in the utilisation of food waste, through enzyme synergistic degradation, as a potential feedstock for biofuel production.

Food processing waste: Problems, current management and prospects for utilisation of the lignocellulose component through enzyme synergistic degradation

Anaerobic treatment of cassava starch extraction wastewater using a horizontal flow filter with bamboo as support

https://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_6/b_fdi_35-36/41166.pdf

C. Segretain

Papers

Methanogenic fermentation of cassava peel using a pilot plug flow digester