Photoacoustic-based sensor for real-time monitoring of methane and nitrous oxide in composting

Abstract The emission of greenhouse gases by biological systems has caused damage to the environment. Thus, sensitive, efficient and accurate techniques have been required to monitor these gases. In this article, the gas dynamics in the composting of an agricultural waste (horse bed and lettuce) was studied. The progress of composting was red accompanied by monitoring O2 and CO2 gases and temperature. The results showed that in the thermophilic phase the composting was predominantly aerobic. Photoacoustic spectroscopy was used throughout the process to monitor the dynamics of the greenhouse gases N2O and CH4. The technique was effective in identifying both gases, and when combined with the convolution approach using the absorption lines from the molecular spectroscopic database (HITRAN), it also allowed the quantification of them.