Simultaneous H2S mitigation and methanization enhancement of chicken manure through the introduction of the micro-aeration approach.

The impact on H2S alleviation and methane yield enhancement after submitting the anaerobic digestion of chicken manure to a finite amount of air was investigated. The largest reduction in the H2S biogas content (58% lower) occurred when air intensity of 30 ml/g VSin was injected into the reactors. Consequently, a maximum methane yield (335 mL-g VSin-1), which was 77% higher than the control, was concurrently achieved. Slight sulfate accumulation (<330 mg L-1) was observed inside the micro-aerated digesters with higher air intensities, suggesting a suppression of sulfide inhibition. Bacterial diversity/richness was enhanced in these digesters while the relative abundance of Methanocelleus increased by 36%. The most important contributing factor to enhancement was the synergistic effect resulting from increments in the hydrolysis rate and the suppression of sulfide inhibition. The results highlighted the potential of in situ H2S mitigation with the added benefit of methane yield enhancement.