土木環境工学ジャーナル

Greenhouse Gas (GHG) Emissions from Mechanically Ventilated Deep Pit Swine Gestation Operation

Abstract

Shafiqur Rahman, Dongqing Lin and Jun Zhu

Emission of greenhouse gases (GHGs) from mechanically ventilated deep pit manure storage was monitored in a swine gestation operation. Air samples were collected from pit exhaust fans at different times of the year (fall, summer, and spring) using a vacuum chamber and Tedlar bags. GHGs concentrations were measured with a greenhouse gas chromatograph (GC) within 24 hours of collection. Air flow rates from exhaust fans were measured using a 160 mm bi-directional Gill propeller anemometer and the ventilation rate was determined as the summation of air flow rates from all fans. The average methane (CH4) concentration was 88±61 ppm and CH4 concentration differences were statistically significant among sampling dates and seasons. The carbon dioxide (CO2) concentration followed the same trend as CH4. The average CO2 concentration was 1105±1063 ppm. Nitrous oxide (N2O) concentrations ranged from 0.02 to 0.66 ppm. Methane emissions varied between 115.94 to 572.18 g d-1 AU-1 and higher methane emission was observed during summer (480.28 g d-1 AU-1). The average carbon dioxide emissions varied from 5.35 to 15.83 kg d-11 AU-1, whereas average N2O emissions varied from 0.06 to 7.30 g d-1AU-1. Significant variation of GHG concentrations and emissions were observed among fall, summer and spring seasons.