Effects of aeration rate on the cornstalks used for filtration of anaerobically digested manure centrate direct composting process: Maturity and gas emissions

Abstract

This study aimed to clarify the effect of the aeration rate on the maturity and gas emission during the direct composting process of the cornstalks for ADMC filtration under three aeration rates of 0.05 (R1 0.05), 0.1 (R2 0.10), and 0.15 (R3 0.15) m3/m3 min for the 21-day composting experiment. The results showed that the temperature of R3(0.15) treatment was lower than the others during composting. All treatments could maintain high temperatures (>50 °C) for more than 5 days, meeting the Chinese national standard for organic fertilizer production. The cumulative CO2 emission of the R1(0.05) treatment was the highest, which was 36.59% and 33.04% higher than the R2(0.10) treatment and R3(0.15) treatment, respectively. R1(0.05) treatment is not conducive to N2O emissions, and R3(0.15) treatment is not conducive to CH4 emissions. The cumulative emissions of NH3 and sulfur-containing odor in the R1(0.05) treatment were the lowest, and the cumulative emissions of H2S, C2H6S, and COS in the R3(0.15) treatment were the highest. Based on the comprehensive comparison, the recommended aeration rate for the cornstalks after the ADMC filtration direct composting is 0.05 m3/m3 min. The results can provide a theoretical basis and measures for the process parameters of the cornstalks for ADMC filtration direct composting.