During the last years, there is a need to plan strategical investments to reduce Wastewater Treatment Plant (WWTP) odour impact, which it is generally carried out by covering and deodourizing the main process units involved.

   Odour dispersion modelling software combined to dynamic olfactometry is the standard technique conducted to evaluate the odour impact studies. However, the results obtained by this methodology strongly depend on the emission sources set in the software. Thus, this study is focused on providing a dynamic odour impact assessment using CALPUFF software simulations, calculated under different “what-if” scenarios, providing a new approach to define the calibration of the emission sources.

   The Graz Lagrangian (GRAL) system is a Lagrangian particle model with a free Graphic User Interface (GUI) available in both Linux and Windows and it is well know among odour modellers. Now the developers have released the version 21.09 with plenty of bug fixes and new features.

    One more year, the GRAL GRAMM team have been working on changes and modifications in the code, and correcting bugs. This is the list of new features and bugs corrected for GRAL, GRAMM and the Graphic User Interface (GUI) for this release.