Online measurement of odorous gases close to the odour threshold with a QMB sensor system with an integrated preconcentration unit

摘要

Today odour measurement close to the odour threshold can be performed only by classical olfactometry. Classical olfactometry is an expensive and time-consuming method that is not suitable for continuous monitoring as needed by operators of compost facilities. This paper describes a system consisting of a quartz microbalance (QMB) sensor array with an integrated preconcentration unit which is able to measure odorous gases below the odour threshold. The system is developed for use in connection with biofilters in biological waste utilisation (compost facilities). The system is highly sensitive to the main odorous components of waste gas, e.g. limonene, 2-butanone or ethyl acetate. Moreover, the system evinces linear behaviour over a wide range between the odour threshold and some hundred parts per million. It was evaluated both in the laboratory and in field measurements, and it shows very good sensitivity and stability about the tested time in the field measurements (2 weeks).