Abstract
Valorization of agro-food waste through anaerobic digestion (AD) is gaining prominence as alternative method of waste minimization and renewable energy production. The aim of this study was to identify the key parameters for digester performance subjected to kinetic study and semicontinuous operation. Biochemical methane potential (BMP) tests were conducted in two different operating conditions: without mixing (WM) and continuous mixing (CM). Three different substrates, including food waste (FW), chicken dung (CD), and codigestion of FW and CD (FWCD) were used. Further kinetic evaluation was performed to identify mixing’s effect on kinetic parameters and correlation of the kinetic parameters with digester performance (volatile solid removal (VS%) and specific methane production (SMP)). The four models applied were: modified Gompertz, logistic, first-order, and Monod. It was found that the CM mode revealed higher values of Rm and k as compared to the WM mode, and the trend was consistently observed in the modified Gompertz model. Nonetheless, the logistic model demonstrated good correlation of kinetic parameters with VS% and SMP. In the continuous systems, the optimum OLR was recorded at 4, 5, and 7 g VS/L/d for FW, CD, and FWCD respectively. Therefore, it was deduced that codigestion significantly improved digester performance. Electrical energy generation at the laboratory scale was 0.002, 0.003, and 0.006 kWh for the FW, CD, and FWCD substrates, respectively. Thus, projected electrical energy generation at the on-farm scale was 372 kWh, 382 kWh, and 518 kWh per day, respectively. Hence, the output could be used as a precursor for large-scale digester-system optimization.
Highlights
Improper management, a series of landfill problems, and population growth have created an alarm regarding sustainable food waste (FW) management
The Biochemical methane potential (BMP) tests of single substrates of FW and chicken dung (CD) and codigestion of FWCD were carried out to investigate the potential for biogas production in two operational conditions
The results indicated that the application of codigestion significantly improved energy generation, producing about 518 kWh, which was 28% and 26% higher than energy generated in bioreactors using a single substrate of FW and CD
Summary
A series of landfill problems, and population growth have created an alarm regarding sustainable food waste (FW) management. FW generation in the United States has increased significantly with time. The FW production for commercial, Fermentation 2022, 8, 28. Fermentation 2022, 8, 28 residential, and institutional samples was reported to have no significant difference at. This is equivalent to 35.5 million tons of FW disposed annually [1]. Inadequate disposal or treatment of FW may lead to detrimental effects on human health and the environment (such as odor problems, pests, leachate, and pollution) [2]. Many studies have highlighted the potential of FW in energy generation using materials such as biogas, biofertilizers, etc. The valorisation of FW through anaerobic digestion (AD) for biogas production is at the forefront of the renewable energy discussions in recent times [6]
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