2022 Volume 12 Issue 1 Pages 129-135
Hydrogen sulfide (H2S) in biogas resulting from anaerobic digestion process is unwanted trace compound, because it is toxic and can corrode biogas engine. This study aimed to compare the 2 desulfurization methods, air injection and iron oxide pellets addition, on H2S removal and quantity and quality of biogas. The experiment was carried out with two floating drum digesters (1 m3 each) constructed at Royal University of Agriculture, Phnom Penh, from January to August 2020. Three levels of air injection at 2%, 4%, and 6% of O2 regarding the daily biogas production and iron oxide pellets application at 1 kg, 2 kg, and 4 kg per m3 of biogas were applied to remove H2S in biogas from different raw materials of pig manure and food waste. The amount of daily biogas production was quantified by gas flow meter, also gas quality was measured using a GEM5000 gas analyzer. The experimental results indicated that food waste had higher daily biogas production comparing to pig manure in both desulfurization methods. Biogas from food waste increased from 544 L d-1 without iron oxide pellets addition (0 kg) to 657 L d-1 with 4 kg iron oxide pellets addition; and to 566.5 L d-1 with 2% of injected O2. To the contrary, desulfurization for pig manure with 2% of O2 and 1 kg of iron oxide showed high daily biogas yield of 348 L d-1 and 340 L d-1, respectively. For raw materials of pig manure, in both desulfurization methods, had higher CH4 content than food waste. Air injection was more effective in H2S removal than iron oxide for both substrates, but higher level of H2S reduction was observed with pig manure. Accordingly, it was concluded that desulfurization methods with air injection and iron oxide pellets addition were effective in biogas production as well as H2S removal, but a clear trend appeared in the raw material of food waste.
