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SOLVAir case study A2A AMBIENTE S.p.A.

Case Study : A2A AMBIENTE: A Waste-to-Energy plant in Italy

Key Facts & Figures - 2019

  • >540 ktons of municipal solid waste treated in 2019 on 3 incineration lines
  • 380 GWh electricity produced in 2019
  • Approx. 450 GWh heating power produced in 2019
  • Flue gas treatment lay-out: Electrostatic Precipitator (ESP) + SOLVAir® S300 + Bag Filter + Selective Catalyst Reduction (SCR)
  • Emission values achieved at stack far below the permit


A2A AMBIENTE S.p.A. WtE Milan overview:

A2A AMBIENTE S.p.A. Waste-to-Energy plant in Milan, Italy is in operation since 2001. The original flue gas treatment was based on dry injection of hydrated lime. In 2007 the injection of lime was replaced by SOLVAir S300® dry sorbent injection.

Effective SOx, HCl and NOx mitigation

The switchover was motivated by the need to comply to more challenging emission limits set on acid pollutants, especially for SOx, HCl and for NOx.

DeNOx Selective Catalyst Reduction (SCR) Installation

In 2008 A2A AMBIENTE S.p.A. installed a DeNOx Selective Catalyst Reduction (SCR) tail-end system. SOLVAir® removes effectively the SOx from the gases so the SCR can work without clogging issues. The operating temperature for dry sorbent injection (approx. 190°C) avoids the need to re-heat the gas for the DeNOx operation.


What SOLVAir® did for A2A AMBIENTE S.p.A.

High pollutants removal rates

SOLVAir® was able to achieve great pollutants removal rates :

The use of sodium bicarbonate in the flue gas cleaning process is a technical solution of proven effectiveness and reliability for the control of acid gas emissions of the Milan Waste-to-Energy plant.

Luca Carpinelli, A2A AMBIENTE Milan WtE Plant Manager

Strong efficiency energy production

The plant is located in the North West of Milan, Italy and is a precious energy source (electricity and heating) for the city.

The plant produces electrical and thermal energy from municipal solid waste, downstream of selective waste collection, as part of an integrated waste management system.

In 2019, the plant was able to provide heating to more than 37,000 households, producing hot water that is conveyed under pressure through underground pipes to the homes of some areas of the city and to users of neighboring municipalities connected to the district heating network.

The electrical energy produced by the plant in 2019 covers the annual energy consumption of about 115,000 families.


Benefits for A2A AMBIENTE S.p.A.

A flexible solution according to changing regulations and capacity

SOLVAir® proved to be very flexible as it let A2A AMBIENTE to target lower emission limit values for acids along time. For instance, no significant modification was needed when A2A AMBIENTE implemented in 2015 a change in the cogenerative asset and a retrofitting to increase their waste treatment capacity.

Residues recycling in SOLVAL®

SOLVAir® also offers recycling services for their sodium-based residues in its SOLVAL® facility located in Italy. By treating the process residues to replace the natural brine used in soda ash production plants, the residues of flue gas cleaning process can be efficiently recovered.

Know more about our recycling services


Requirements of the legislation and results - 2019

A2A already complies with the emission limits of the new BREF Waste Incineration as you can see in the table below:



Nitrogen oxides


Sulphur oxides


Hydrochloric acid


Carbon Monoxide




Total organic carbon




Limit A.I.A

(daily average)








Emission value

(daily average)








For its company culture A2A AMBIENTE has always aimed to be in the top-class in technology: since the beginning our relationship has been challenging for us and enhanced our motivation to provide better solutions to meet their needs

Stefano Brivio, SOLVAir® Head of Sales Italy