Electronic Nose Network

OdoWatch® merges continuously the odour data with the incoming weather data to display on the screen the odour plume superimposed on a map of the site and its surroundings.


When OdoWatch® is fed with weather forecast data, it will also predict the odour impact up to 24 hours ahead. The operator can take appropriate steps in order to prevent the predicted impact.


OdoWatch® can:

  • Distinguish between the odours generated by the site and those originating from other sources ;
  • Continuously archive data in case of odour complaints by the public ;
  • Identify the main odour sources ;
  • Issue alerts when preset thresholds are exceeded ;
  • Taking appropriate steps in case of operational incidents.


Veolia Water Technologies & Odotech

Veolia Water Technologies has contracted an exclusive agreement with Odotech. (See Odotech Website)


Features & Benefits

OdoWatch® is the world's first electronic-nose network for 24/7 wireless odour monitoring.



Electronic Noses

  • Sensor matrix with an array of up to 64 different sensors
  • Remote sensor calibration & software updates
  • Wireless communication
  • Independent power supply

Weather Tower

  • Wireless communication
  • Provides weather forecast for odour plume calculations

Monitoring Centre (display)

  • Odour recognition & quantification algorithms
  • Source characterisation algorithms
  • Utilizes weather tower data
  • Computes odour plume
  • Calculates odour emission rates
  • Issues alerts when preset thresholds are exceeded
  • Predictions over the next 2, 4, 6, ... 24 hours
  • On-demand reports at any time
  • Archives data for future reference
  • Capacity for 250 strategically-placed e-noses



  • Distinguish between the odours generated by the site from those originating elsewhere
  • Continuously archive the results for later reference in case of complaints from neighbors
  • Identify the most troublesome odour sources
  • Issue alerts when pre-set thresholds are exceeded
  • Enable quick action in the event of operating incidents



OdoWatch® can be used for real-time odour monitoring at municipal and industrial sites, including :

  • Waste disposal sites
  • Water treatment sites
  • Composting sites
  • Industrial plants
  • Agricultural sites


The Need for Odour Monitoring

The need for odour control is particularly acute when dealing with wastewater or industrial sites close to residential areas, where nuisance odours give rise to widespread complaint. The difficulty is that when neighbours complain about a smell, they are often vague about when it occurred, how long it lasted, its intensity or character. Humans' experience of odours is extremely subjective, perhaps because human DNA contains one gene for hearing, three for vision, 12 for taste, and 1000 for smell. But it does mean that apart from creating citizens' committees and spending a lot of money on neutralizing equipment and chemicals, there is not much that a site manager can do. Until now, it was impossible to monitor an odour 24 hours a day, and it is equally difficult to establish whether a chosen solution is working or not.


Example: OdoWatch® for a Wastewater Plant

Each e-nose contains a matrix of sensors optimized for the odours of the site. They sample the air 24 hours a day, and transmit the results to the Central Control Unit where the OdoWatch® software merges them with the meteorological data in order to model the atmospheric dispersion of odours.The diagram below shows an OdoWatch®  system designed for a wastewater treatment plant.


The operator therefore sees the effect of site odours on the neighborhood, at-a-glance. When using meteorological forecast data, OdoWatch® can also predict the odour impact up to 24 hours ahead. This enables the operator to take steps to reduce the odour and prevent the nuisance from occurring.



The OdoWatch® is comprised of three main systems:

  • The Electronic Noses, or "e-noses, " which measure the odours
  • The Central Control Unit, comprised of the OdoWatch® software for atmospheric dispersion modelling
  • Weather tower on-site


Electronic Noses

An Electronic Nose is comprised of the aspirator for sampling, the measurement chamber and the communication system, all contained within a single enclosure.

In each Electronic Nose, a micropump aspirates an air sample once per minute and forwards this to the internal measurement chamber. The optimised sensors in the measurement chamber react differently to odours. (These sensors are not specific to a particular chemical, like other technologies who develop and use H2S sensors, but instead are specific to the odours and processes on your site.) The presence of odourous molecules absorbed by the metal oxide sensor surface modifies the sensor conductance, which alters the output voltage. The sensor signals are treated by the signal processing cards of each Electronic Nose, then sent to the internal communication system.

The Electronic Noses measure odour concentration in odour units at or near the source. The accuracy of the measurement can be verified by comparing the olfactometer result and the EN reading.


Central Control Unit

Each Electronic Nose unit contains a signal transmission system, used to forward the odour readings to the Central Control Unit, a PC equipped with the OdoWatch® software that merges the odour data with the meteorological data from the site weather tower as well as with other parameters in order to determine the odour plume.