Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8869827 | Waste Management | 2018 | 15 Pages |
Abstract
Substrate-induced instability of anaerobic digestion from fruit and vegetable waste (FVW) results in low biogas yield. In this study, substrate management through fruit to vegetable mix ratio in a two-stage semi-continuous digester was investigated as a pathway for optimality of yield. The experiment conducted over 105â¯days with 62.52â¯kg of FVWs sourced from Joburg Market, South Africa showed that a stable process was achieved at a fruit to vegetable waste mix ratio of 2.2:2.8. At this ratio, optimal organic loading rate ranged between 2.68 and 2.97â¯kgâ¯VS/m3-d which resulted in a specific biogas yield of 0.87â¯Nm3/kgâ¯VS with 57.58% methane on average. The results of the experimental study were used as a feasibility assessment for a full-scale 45â¯tonnes/d plant for Joburg Market considering three energy pathways. The plant will produce 1,605,455â¯Nm3/y of biogas with the potential for offsetting 15.2% of the Joburg Market energy demand. Conversion of all biogas to biomethane was the most economically attractive energy pathway with a net present value of $2,428,021, an internal rate of return of 16.90% and a simple payback period of 6.17â¯years. This route avoided the greenhouse gas emission of 12,393â¯tonnes CO2, eq. The study shows that the anaerobic digestion of FVWs as sole substrate is possible with financial and environmental attractiveness.
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Authors
S.O. Masebinu, E.T. Akinlabi, E. Muzenda, A.O. Aboyade, C. Mbohwa,