CAP Amiacque – Civil wastewater treatment plants

The integrated solution: CAP Amiacque
Total Odour Management: effective tools for reliable measurements

In 2017, Osmotech was awarded the contract for the supply and installation of a continuous monitoring system of odour emissions in 4 wastewater treatment plants in the Milan metropolitan area managed by CAP Amiacque.
These are the systems of Assago, Bresso, Canegrate and Pero.

CAP Amiacque wished to equip these operations with an effective system for the objective measurement of odour emissions. The objective was to obtain a reliable overview of olfactory impact, in order to plan the actions required to mitigate any nuisance to the local community.

Osmotech has designed an integrated solution for each treatment plant, which includes:

• multisensor control units for continuous monitoring of odours (electronic noses)
• ultrasonic weather station with PLC for data transmission via GSM
• mathematical odour dispersion simulation software for reliable estimations and forecasts of olfactory impact in the area
• TOM – Total Odour Management software for management of olfactory nuisance reports.

Amiacque is an operating company in the CAP Group, a public shareholding company that is the single manager of the integrated water services in the province of Milan. It deals with 61 wastewater treatment plants, including the 4 mentioned above.

In relation to the operations completed, 34% of overall waste treated by the CAP Group will be equipped with continuous odour monitoring.

Odour Protocol, the foundation of an effective system

In January 2018 the Odour Protocol was started, to identify all odour sources, select the specific sensors for the monitoring control units and position the stations in the most appropriate locations.

After collecting the samples, the Osmotech Laboratory of Pavia (accredited to the standard UNI EN 13725:2004) conducted the emissions analyses:

• olfactometry analysis to determine the odour concentration levels for each individual source;
• GC/MS speciation chemical analysis to identify all compounds responsible for the odours.

This has enabled precise calibration of the monitoring system, configured according to the specific characteristics of the sites under observation.

Following this, using mathematical models of odour dispersion the Osmotech engineers studied the meteorological framework of the area and identified the relevant sensitive receptors.

By cross matching the data, this led to a definition of the odour potential of each system, and the relative impact on the area.

Experience that counts: training the electronic noses

The Osmotech technicians have  trained the ETL 3000 Orion multi-sensor control units to recognise the odour emissions of the treatment plants and calibrated the electrical response of the sensors in odour units.
This training process involved additional sampling and olfatometric analyses on each source.

The correct and precise calibration of odour is a decisive factor for the validity of measurements and efficient monitoring.
The location of the control units has also been thoroughly researched, positioned at the emission sources or on the perimeter of plants, taking into account weather parameters and the location of sensitive receptors.

Managing and verifying complaints using TOM

The Amiacque system combines mathematical modelling with automatic management of odour nuisance reports via the software TOM – Total Odour Management.

This tool uses the AERMOD dispersion models, weather data and odour measurements to supply a graphic representation in real time  of the impact on the area (plume): extent, intensity and direction.

TOM receives and records reports from local residents, checks these reports by matching them with odour events in the area at that time, and then displays them on a map highlighted by category (red = justified, green = not justified, yellow = pending verification).

Odour Field Inspection for system validation

Six months after testing, the monitoring system is validated by conducting an Odour Field Inspection using the plume method (to standard UNI EN 16841-2:2017).
The inspection is performed by trained assessors and is aimed at verifying the system, and repeating the calibration set-up procedure.
Osmotech is the only Italian laboratory accredited  for Field Inspection (UNI EN 16841-1:2017 grid method).

For further details, see our olfactory impact monitoring system.