Estimation of Greenhouse Gas Emission Factor During Hanwoo Manure Composting

Accurate estimation of climate-altering gases, such as methane and nitrous oxide, from livestock waste treatment is critical for establishing national inventories. This study aims to monitor and analyze the emission characteristics of these gases during the treatment process at an operational Hanwoo (Korean cattle for beef) farm in Republic of Korea to develop country-specific metrics. A full-scale compost shed was modified into a 2400 m³ flux chamber equipped with fans to control airflow at 183 m³·min^-1. Real-time gas concentrations were measured using enhanced-performance laser-based analyzers across summer, autumn, and winter. The results indicated that mean emissions for both methane and nitrous oxide were highest in summer, followed by winter, and lowest in autumn. Daily patterns revealed higher hourly mean emissions during the morning and afternoon. The final estimated emission factors were 1.28 kgCH₄·head^-1·yr^-1 and 0.039 kgN₂O· head^-1·yr^-1. These values are relatively lower than those reported in previous studies. These values were lower than those reported in several previous studies. Differences in facility scale and operating conditions may partly explain this result; however, potential underestimation due to non-uniform airflow should also be considered.