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The study aimed to introduce biogas as an alternative source of energy for rural cattle farmers in the Malutia-Phofung municipality in the Free State Province, South Africa. To augment the rural farming community's adoption of the biodigester technology the following initiatives were undertaken: (i) a situational analysis (or diagnostic survey); (ii) training on biogas production in an integrated crop-livestock-bioenergy system; (iii) installation of the biodigesters; and (iv) monitoring and evaluation of the biogas production. Results on the diagnostic survey showed that the main source of energy for cooking was wood in all the farms and availability of water was not a constraint. Prefabricated biodigesters of 6m 3 -12m 3 were installed in all the households and, after continual feeding of the units with cattle dung, the production of biogas increased gradually. Monitoring of biogas production showed that, in two-thirds of the households, 80% of their cooking needs were met in summer, while in winter biogas production was minimal due to extremely cold weather. Challenges faced included non-adherence to a feeding regime -resulting in a blockage of the biodigesterand lack of feeding. Generally, farmers in the study area showed a high appreciation of the biodigester technology. ; M.I. Tongwane https://orcid.org/0000-0002-8003-909X; P.M. Nakana https://orcid.org/0000-0003-4521-7310; V.K. Mliswa https://orcid.org/0000-0003-3651-1366; M.I. Motsepe https://orcid.org/0000- 0002-1950-9320; S. Madikiza https://orcid.org/0000-0002-7610-5381

The goal of this paper was to assess the possibilities for one-stage reactor anaerobic digestion processing of fruit and vegetable biomass within a biorefinery concept for optimum products. Co-digestion was the simplest strategy to implement to increase product yield among the variables tested (pH, ultrasonification, and co-digestion). Methane yields from co-digestion of fruit and vegetable waste (FVW) and pig manure (PM) ranged from 318 to 434 NmL /g VS, with the highest yield (434 NmL /g VS) achieved at a co-digestion ratio of FVW75:PM25, representing a 20% increase over the methane production from FVW alone. The pH value was determined to be the most effective variable for enhancing methane production, with pH = 8 producing the maximum cumulative methane yield of 497 NmL/g VS. There was no significant change in the composition of volatile fatty acids (VFA) with pH in terms of dominant product type; valeric acid was the predominant VFA synthesized at all starting pH values except pH = 12, where formic acid was the predominant acid formed. As a digestate posttreatment procedure, hydrothermal carbonization was combined with anaerobic digestion. At 200 °C, the maximum hydrochar yield production was 58.2%, with a higher heating value of 10.75 MJ/kg.