In the 90’s, the wastewater management authority for the Paris area (‘Syndicat interdépartemental pour l'assainissement de l'agglomération parisienne’ - SIAAP) established various odour survey tools in order to understand the link between odours and significant operating events at its Waste Water Treatment Plant (WWTP) and in the sewage network. These tools include monitoring stations (weather stations, sulphur compounds analysed with stationary and mobile analytical instruments), human observers (daily odour patrols, voluntary citizens’ panels and citizens’ complaints logbook), and air dispersion modelling (three-dimensional numerical CFD (Computational Fluid Dynamics) dispersion allowing real-time and forecast odour dispersion).
Starting in 2017, some important changes were initiated in order to improve this monitoring system. Indeed, as a response to important redesign works of one of their WWTPs (Seine Aval), the SIAAP needed to demonstrate a monitoring tool with a high level of confidence, especially during the crucial commissioning period.
Because the previously operated daily patrols showed some limitations, one of the first steps was to implement a new protocol for field investigations and data treatment. The chosen method is, for the most part, inspired by the new standards: EN 16841-1 and EN 16841-2 - Determination of odour in ambient air by using field inspection - Grid method and Plume method. The originality of the new protocol implemented by SIAAP lies in the fact that both methods – Grid method and Plume method – are merged and adapted to needs and means of the SIAAP, in order to collect relevant data.