Iron-fortified Anaerobic Co-digestion Performance of Kitchen Waste and Pennisetum Hybrid

Element iron as an essential trace metal has the function of facilitating the process of anaerobic digestion and consequently improving the biogas yield. Accordingly, the mixture ratio of kitchen waste and Pennisetum hybrid was optimized for the codigestion system, and the effects of iron powder (IP), iron protoxide (FeO), and zero valent iron (nZVI) on the performance of the co-digestion system were studied under the batch mode and mesophilic condition. The results showed that the mixture ratio of 0.5:9.5 of kitchen waste and Pennisetum hybrid achieved a higher specific biogas yield of 338.32 +/- 10.44 mL/g VS, which increased by 52.60% in comparison with that of the mono-digestion of Pennisetum hybrid. Based on the results, adding IP, FeO, and nZVI to the co-digestion system improves the biogas yield. Among them, a maximum specific biogas yield of 406.73 +/- 61.28 mL/g VS was obtained by adding IP at the dosage of 0.5% and increased by 39.50% in comparison with the control system. For the co-digestion system with nZVI and FeO addition, an increase of 0.64% and 29.60% in specific biogas yields was achieved at the same dosage 0.5%