In the second half of 2009 on Odour Field Inspection lasting six months according to German Guideline VDI 3940 was completed, with the aim of measuring the odour impact generated by a municipal waste treatment plant with anaerobic digestion system in Bassano del Grappa. A group of 16 panellists was recruited and selected according to EN 13725, and was trained to recognise typical plant emission odour: biofilter, biogas, green waste. Following the German Guidelines, a grid of squares with sides of about 200 m was built on the territory around the plant, generation 48 intersection points; twelve different paths crossing four non-adjacent vertices were created where panellists performed odour assessments and subsequently filled in a form. During the campaign every point was visited 26 times by different panellists at different hours and week days (except for night time, from 1 a.m. to 7 a.m.). Collected data were processed and isofrequency curves for every kind of plant odour were generated; a different frequency distribution can be observed for each odour, due to the different source and flowrate and intensity. Main difficulties found during organisation of the study, as well as odour recognition problems, will be described.
