GIADA Project – the Vicenza region tanning hub

Valle del Chiampo Tanning centre – The innovative approach of the GIADA Project
Odour monitoring and Field inspection

This case regards the vast campaign for assessing the olfactory impact conducted by Osmotech in the Vicenza tanning district in Valle del Chiampo.
The task was assigned by the Province of Vicenza as part of the GIADA Project, Integrated Environmental Management in the tanning district, run by the District Agency for the Environment together with local administrative authorities and involving local businesses and residents.
Experience has shown us that the problem of olfactory pollution can be dealt with adopting a positive and conscientious approach, making use of techniques such as Odour Field Inspection conducted between 2017 and 2018 at the Fonderie di Montorso SpA foundry in Montorso Vicentino.

2016-2017 – The first recognition

We had spoken of the GIADA project in a post illustrating the initial inspection activities.
The initial phase of odour detection and analysis – between 2016 and 2017 – was aimed at creating an objective framework of the emissions with a realistic representation of olfactory impact in the area.
The intervention was performed by:

  • sampling, chemical analysis and olfactometric analysis of the odour emissions from 9 plants, specified by the Province and local authorities: 3 tanning plants, 3 chemical plants, 1 foundry and 2 pig farms. Objectives: characterisation of the odours and calculation of hydrogen sulphide;
  • modellistic study of odour dispersion into the atmosphere, conducting using a Calmet-Calpuff mathematical model in accordance with the reference standards (Guide Lines of the Lombardy Regional Authority, Reg. dir. 15 February 2012 – No. IX/3018). Objective: to track and display the map of olfactory impact generated in the area and perceived by the local population.

This campaign was completed in early 2017 and provided a reliable estimate of the olfactory impact of each plant.

2017-2018 – New monitoring

The second phase of inspections was conducted between October 2017 and February 2018, concentrating on the inspection of 3 of the sites under observation: 1 chemical plant, 1 fertiliser and compost production plant and 1 foundry.
New emission measurements and analyses were performed, establishing the odour concentration and calculating the Odour Emission Rate (OER).
By applying the atmospheric dispersion model, again using the Calpuff model and Calmet meteorological set as in 2016, an updated assessment was obtained of the olfactory impact on the area.

The aim was to compare the odour mapping in the various time periods, to record the progress of the events and verify improvements implemented over time.

Odour Field Inspection in Montorso Vicentino

In the case of the foundry Fonderie di Montorso SpA, in Montorso Vicentino, monitoring was extended with an additional inspection: for around 2 months an Odour Field Inspection (OFI)was conducted, based on human olfactory perception, using qualified and specially trained sniffers to recognise and assess the odours in ambient air. This technique provides even more consistent and realistic information on the diffusion, intensity and frequency of the odour events affecting the population.

In Italy the OFI was implemented in 2017 with the technical standard UNI EN 16841:2017. Osmotech boasts ten years of application experience (since 2009) and is now the first and only Italian olfatometric Laboratory certified to conduct Field Inspections using the grid method (UNI EN 16841-1).

The OFI campaign for the foundry Fonderie di Montorso started on 13 December 2017 and was completed on 20 February 2018. It was conducted both for system odour emissions and to recognise other potential emission sources in the area concerned. The work was divided into several operating phases:

  1. campaign planning and definition of the inspection grid
  2. recruitment and training of the examiners
  3. field inspections
  4. statistical processing of the data and drafting of the olfactory impact maps.

Campaign planning and definition of the inspection grid

Planning of the Field Inspection starts with a preliminary meteorological and geomorphological study of the area, examining various elements to define the inspection grid (calm wind conditions, odour sources, reports of odour nuisance, sensitive receptors).
In this case, the foundry plant was placed at the centre of the grid, with the odour emission point (Flue 32). The observation area was extended to include other impacting sources and receptors in the surrounding area: tanning industries, livestock breeding farms, a system for biogas production from biomass, residential areas in the municipalities of Montorso and Zermeghedo.
Overall this was made up of a land area of approximately 4 square kilometres mapped with a network of 19 inspection cells and 30 measurement stations (grid intersection points), divided into 5 inspection rounds, each containing 6 measurement points.

Recruitment and training of inspectors

The Odour Field Inspectors, who conduct the inspections by sniffing odours and compiling the data record sheets, were recruited from the local residents and underwent tests to verify the olfactory perception threshold (measured at the olfactometer with the European reference substance, n-butanol).
Suitable candidates, i.e. those with an average perception threshold (as specified by standard UNI EN 16841-:2017), were then trained by Osmotech personnel to recognise on site all typical odour emissions of the area.
The same candidates then underwent a second test, to establish the ability to distinguish between different odours to be identified and recorded: “foundry”, “tanning”, “breeding”, “silage” and “biogas” (plus other odours possibly present, to be recorded as “other odour”; the note “no odour” was used to indicate the absence of odour other than that of the ambient background).
Lastly, they were trained and equipped to start the inspections.

Field inspections

In the two months of the OFI campaign, 65 measurement rounds were conducted, with daily outings in different time bands (day and night) according to the set routes and pre-set dates, i.e. without knowing the weather conditions or operating conditions of the plant.
To guarantee statistically significant results, as envisaged by the standards, Field Inspection samplings were planned at random, equally distributed over time and performed by inspectors with maximum shifts.
During the inspections, the Field Inspectors stay at the measurement points for 10 minutes and sniff the area every 10 seconds for a total of 60 measurements, recording the data on the relative form.
A qualified Osmotech operator regularly checks the inspectors on site and ensures the correct measurement procedures.

Statistical processing of the data and drafting of the olfactory impact maps.

All data collected were first validated (according to standard UNI EN 16841), verifying consistency with the weather conditions recorded at the same time by the ARPAV control units.
The data were then processed statistically to obtain the values of hourly odour frequency for each of the grid cells (the frequency is calculated as a ratio between the number of odour hours recorded at the four corners of the cell and total number of hours monitored) and to distinguish the odour contribution of the foundry from the other sources taken into consideration.

The graphic representation of the results are the chromatic isofrequency maps, which display the odour events on the area (total and by single type or sources) with isofrequency areas.
On the chromatic maps, each type of odour corresponds to a colour. The grid cells also display, in tones of varying intensity, the variations in the odour detection percentage.

The complete results of the inspection were officially presented in June 2018.
All documentation can be downloaded from the GIADA Agency website.