Influence of Aeration Method on Gaseous Emissions and the Losses of the Carbon and Nitrogen during Cow Manure Composting

Abstract

The objective of this research was to explore the effects of different aeration methods on NH3 and greenhouse gas (GHG) emissions and the losses of carbon and nitrogen from composting of cow manure and corn stalks in the laboratory-scale reactors. Here, we designed three treatments, including continuous aerated treatment C1 (aeration rates 0.21 L·kg−1 dry matter (DM)·min−1) and intermittent aerated treatments I1 (aeration rates 0.42 L·kg−1 DM·min−1; aerate 10 min, stop 10 min) and I2 (aeration rates 0.84 L·kg−1 DM·min−1; aerate 5 min, stop 15 min). The results showed that the physicochemical parameters (temperature, pH values, and germination index) of composting products met the requirements of maturity and sanitation. Compared with continuous aerated treatment C1, the cumulative NH3 emissions of I1 and I2 treatments decreased by 24.37% and 19.27%, while the cumulative CO2 emissions decreased by 13.01% and 20.72%. On the contrary, the cumulative N2O emissions of I1 and I2 treatments increased by 22.22% and 43.14%. CO2 emission was the principal pathway for the TOC losses, which comprised over 65% of TOC losses. C1 treatment had the highest TOC losses due to its highest cumulative CO2 emissions. The TN losses of I1 and I2 treatments reduced 9.07% and 6.1% compared to C1 treatment, so the intermittent aerated modes could reduce the TN loss. Due to the potential for mitigation of gaseous emissions, I1 treatment was recommended to be used in aerobic composting of cow manure.