Effects of Fe2+ on the Anaerobic Digestion of Chicken Manure: A Batch Study

Trace elements are considered to be essential for anaerobic process. Laboratory-scale batch studies were undertaken to evaluate the effect of Fe²⁺ on the biogas production from chicken manure at mesophilic condition (37 ±1°C). The biogas production increased by 26.6% within 11 days when Fe²⁺ concentration was 25 mg/L with VS concentration of 50g/L. With the increase of Fe²⁺ concentration, the biogas production was improved significantly. The biogas production increased by 48.7%, 52.1% and 54.8% at Fe²⁺ concentration of 100, 250, 500 mg/L. However, the biogas production was inhibited by 57.9% when Fe²⁺ concentration was as high as 5000 mg/L. Additionally, the Gomperz equation and first-order dynamic model equation can well describe the biogas process using the batch experimental data.