Real Time Monitoring of VOC and Odours Based on GC-IMS at Wastewater Treatment Plants

Abstract

Emissions of VOCs and odours at wastewater treatment plants are a frequent cause of concern due to their general proximity to residential areas. An increase in environmental awareness and the existence of regulations can lead to greater complaints amongst citizens. In addition, odours that are considered as unpleasant can be perceived as being linked to health concerns in local populations. Thus, VOC and odour emission control has become an issue of utmost importance at wastewater treatment plants, and subsequently the monitoring of emissions is an equally significant task. The aim of this study is to evaluate a GC-IMS (Gas Chromatography - Ion Mobility Spectrometer) as a tool for continuous monitoring emissions from wastewater treatment plants, offering the possibility of producing fast measurements for the determination of chemical fingerprints of VOCs and odorous compounds. Air samples from different process units at a metropolitan wastewater treatment plant in the UK were collected and analysed by GC-IMS and dynamic olfactometry according to EN 13725. The GC-IMS system was used to determine magnitude of individual VOC emissions and investigate whether process types could be characterised by unique VOC fingerprints. The results showed different chemical fingerprints of volatiles in each sample and a correlation between the magnitudes of VOCs detected against results obtained by olfactometry. This suggests that GC-IMS has the potential for use as a beneficial analytical technique for the monitoring odour compounds, with greater potential than conventional electronic noses due to its higher sensitivity.