An Overview of Biogas Production from Anaerobic Digestion and the Possibility of Using Sugarcane Wastewater and Municipal Solid Waste in a South African Context

Abstract

Bioenergy production from waste is one of the emerging and viable routes from renewable resources (in addition to wind and solar energy). Many developing countries can benefit from this as they are trying to solve the large amounts of unattended garbage in landfills. This waste comes in either liquid (wastewater and oil) or solid (food and agricultural residues) form. Waste has negative impacts on the environment and, consequently, any form of life that exists therein. One way of solving this waste issue is through its usage as a resource for producing valuable products, such as biofuels, thus, creating a circular economy, which is in line with the United Nations (UN) Sustainable Development Goals (SDGs) 5, 7, 8, 9, and 13. Biofuel in the form of biogas can be produced from feedstocks, such as industrial wastewater and municipal effluent, as well as organic solid waste in a process called anaerobic digestion. The feedstock can be used as an individual substrate for anaerobic digestion or co-digested with two other substrates. Research advancements have shown that the anaerobic digestion of two or more substrates produces higher biogas yields as compared to their single substrates’ counterparts. The objective of this review was to look at the anaerobic digestion process and to provide information on the potential of biogas production through the co-digestion of sugarcane processing wastewater and municipal solid waste. The study deduced that sugar wastewater and municipal solid waste can be considered good substrates for biogas production in SA due to their enormous availability and the potential to turn their negative impacts into value addition. Biogas production is a feasible alternative, among others, to boost the country from the current energy issues.

A systematic review of the design considerations for the operation and maintenance of small-scale biogas digesters

“…At lower temperatures, the activity of the microorganisms slows down, reducing the biogas production rate. At higher temperatures, the microorganisms can become stressed and may even die, leading to a complete shutdown of the biogas production process [ [134] , [135] , [136] , [137] ]. Various authors have proposed strategies for controlling the temperature in small-scale digesters [ 42 , 138 ].…”

Current trends and future directions of global research on wastewater to energy: a bibliometric analysis and review

“…It is worth noting that future research on the utilisation of biochar as an aide for increasing anaerobic digestion will have added benefits for the circular economy (WSAA 2023 ), including the use of food-waste-based biochar to increase methane production (Kalengyo et al 2023 ). This could be further expanded to focus on exploring the use of alternative feedstocks such as food waste (Paranjpe et al 2023 ) or agriculture waste (Tshemese et al 2023 ) to improve the efficiency of anaerobic digestion.…”

Influence upon Biogas Production of the C/N Ratio and the Heavy Metal Incidence in the Manure Composition

“…Likewise, the quality of the compost is influenced by the C/N ratio [38] (p. 37). The recommended C/N ratio for anaerobic degradation is considered 20-30 [27,29], but some researchers think that lower C/N ratios (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) can produce good results [39] (p. 121-181). Since a ratio lower than 20 can inhibit the process, and a ratio greater than 30 leads to a decrease in the amount of biogas [3,40].…”

“…Biogas is usually obtained through anaerobic digestion (AD), a method that transforms waste into bioenergy [12] (p. 126377). Anaerobic digestion is influenced by several factors, including: waste quality [13] (p. 012113), temperature, pH, C/N ratio [14] (p. 8721-8726), organic loading rate, and hydraulic retention time (HRT) [15] (p. 13).…”