Monitoring the exhaust air of a compost pile as a process variable with an e-nose

In this paper, the monitoring of the composting process with an e-nose is presented. An emission chamber is developed for this purpose and put on a household waste compost pile. A lab-made e-nose with metal oxide sensors is located at the exit of this chamber. Simultaneously to the e-nose measurements, air sampling on sorbent tubes as well as physico-chemical analysis are realised. The adsorbed air samples are analysed in the lab by gas chromatography coupled to mass spectrometry (GC–MS). In addition, some parameters of the composting process are collected (compost temperature, age of the pile, date of the aeration). Correlation between the sensors and 14 chemical families is determined by principal component analysis (PCA). By canonical analysis, two models are developed and calibrated by the proportion of each chemical family and in function of the compost process events. Thanks to these models, monitoring of various kinds of compost process events is possible with only one measurement device.