Effect of C/N ratio, aeration rate and moisture content on ammonia and greenhouse gas emission during the composting

Abstract

Gaseous emission (N 20, CH 4 and NH 3) from composting can be an important source of anthropogenic greenhouse gas and air pollution. A laboratory scale orthogonal experiment was conducted to estimate the effects of C/N ratio, aeration rate and initial moisture content on gaseous emission during the composting of pig faeces from Chinese Ganqinfen system. The results showed that about 23.9% to 45.6% of total organic carbon (TOC) was lost in the form of C0 2 and 0.8% to 7.5% of TOC emitted as CH 4. Most of the nitrogen was lost in the form of NH 3, which account for 9.6% to 32.4% of initial nitrogen. N 20 was also an important way of nitrogen losses and 1.5% to 7.3% of initial total nitrogen was lost as it. Statistic analysis showed that the aeration rate is the most important factor which could aifect the NH 3 (p = 0.0189), CH 4 (p = 0.0113) and N 20 (p = 0.0493) emissions significantly. Higher aeration rates reduce the CH 4 emission but increase the NH 3 and N 20 losses. C/N ratio could aifect the NH 3 (p = 0.0442) and CH 4 (p = 0.0246) emissions significantly, but not the N 20. Lower C/N ratio caused higher NH 3 and CH 4 emissions. The initial moisture content can not influence the gaseous emission significantly. Most treatments were matured after 37 days, except a trial with high moisture content and a low C/N ratio.