Enhancing Biodegradability of Coffee Husk and Water Hyacinth Using Food Waste: Synergistic and Kinetic Evaluation Under Co-digestion

• Published in: Bioenergy research 2024-09, Vol.17 (3), p.1953-1970
• Main Authors: Ibro, Mohammed Kelif, Ancha, Venkata Ramayya, Lemma, Dejene Beyene, Pohl, Marcel
• Format: Article
• Language: English
• Subjects: Aquatic plants; Biodegradability; Biodegradation; Biogas; Biomedical and Life Sciences; Coffee; Digestion; Floating plants; Food waste; Life Sciences; Mixing ratio; Plant Breeding/Biotechnology; Plant Ecology; Plant Genetics and Genomics; Plant Sciences; Substrates; Synergistic effect; Volatile solids; Water hyacinths; Wood Science & Technology
• ISSN: 1939-1242; 1939-1234; 1939-1242
• DOI: 10.1007/s12155-024-10750-7

Considering the difficulty of digesting coffee husk (CH) and water hyacinth (WH) due to the lignin content, the present study investigated the influence of feedstock mixing ratios on the co-digestion performance of CH and WH with food waste (FW) at 38 ± 1 °C and its kinetics. Food waste was considered as co-substrate due to its ease of digestion. Batch experiments were conducted using CH/WH/FW ratios (100:0:0, 0:100:0, 35:35:30, 30:30:40, 25:25:50, 20:20:60, and 0:0:100 w/w) with total solids (TS) content of about 9.5% (w/v). The results indicated that the addition of FW significantly enhanced WH and CH digestion performance, with the maximum biogas yield of 572.60 ± 2.30 mL/gVS, best synergistic effect of 1.5, highest biodegradability of 89.22%, and a biodegradation rate of 57.82% obtained at a mix ratio of 25:25:50, which was improved by 179.71% compared to CH mono-digestion. In addition, the organic conversion efficiency of TS and volatile solids reached 69.86 and 81.48%, respectively. Conversely, CH mono-digestion yielded the lowest biogas yield of 204.71 ± 10.74 mL/g VS, highlighting its unfeasibility. The modified logistic equation showed the best fit to the experimental data. The optimum CH/WH/FW ratio of 25:25:50 demonstrated the highest biogas yield and methane content at 66.30 ± 0.76%. Graphical Abstract