Key Facts & Figures - 2023
- >580 ktons of municipal solid waste treated in 2023 with 3 incineration lines
- 410 GWh of electricity produced in
- Approximately 450 GWh of heat produced in
- Fume treatment layout: electrofilter (ELF) + SOLVAir® S300 + bag filter + selective catalytic reduction (SCR) system
- The emission values obtained at the stack are much lower than the authorization
Overview of the A2A waste-to-energy plant in Milan
The A2A waste-to-energy plant has been in operation in Milan since 2003. Fume treatment was originally based on the dry injection of hydrated lime. In 2007 lime injection was replaced by dry reagent injection SOLVAir® S300.
Effective reduction of SOx, HCl and NOx
The conversion was motivated by the need to fall within the more restrictive limits imposed for acid pollutants, especially SOx, HCl e NOx.
Installation of DeNOx for Selective Catalytic Reduction (SCR)
In the 2008 S.p.A has installed a tail DeNOx system for selective catalytic reduction (SCR). SOLVAir® effectively removes the SOx from gases, so the SCR can work without clogging problems. The operating temperature at which the reagent is injected dry (approximately 190°C) avoids having to reheat the gas for DeNOx operation.
What SOLVAir® did for A2A
Excellent results in reducing pollutants
SOLVAir® was able to achieve high levels of pollutant removal:
"Due to its corporate culture, A2A has always aimed to be at the forefront of technologies: from the beginning our relationship stimulated us and increased our motivation to provide better solutions to meet their needs."
High efficiency in energy production
The plant is located in the north-western area of Milan and is a precious source of energy (electricity and heating) for the city.
The plant produces electricity and thermal energy from solid urban waste, following separate collection, as part of an integrated waste management system.
In 2023 the plant was able to provide heating to over 40.000 ahousing, producing hot water which is transported under pressure to homes in some areas of the city and to users in nearby municipalities connected to the district heating network.
The electricity produced by the plant in 2023 covers the annual energy consumption of approximately 150.000 families.
The advantages for A2A
A solution adaptable to legislative and capacity changes
SOLVAir® has proven to be very flexible, allowing A2A to reach lower acid emission limit values over time. For example, no significant changes were necessary when in 2015 A2A implemented a change in the cogeneration structure and an adaptation to increase waste treatment capacity.
Recycling of waste at SOLVAL®
SOLVAir® also offers sodium-based waste recycling services at its platform SOLVAL® in Tuscany. The process residues are treated and replace the natural brine used in soda production plants, allowing the residues from fume purification to be efficiently recycled.
Regulatory requirements and outcomes - 2023
A2A already meets the emission limits of the new BREF for waste incineration, as seen in the table:
Ossidi di azoto mg/Nm3 | Ossidi di zolfo mg/Nm3 | Acido cloridrico mg/Nm3 | Monossido di carbonio | Polveri mg/Nm3 | Carbonio organico totale mg/Nm3 | Ammoniaca mg/Nm3 | |
| Limite A.I.A (media giornaliera) | 60 | 15 | 5 | 50 | 3 | 5 | 5 |
| Emissione (media giornaliera) | 39,5 | 1,87 | 2,85 | 5,96 | 0,05 | 0,16 | 0,34 |
"The Silla2 waste-to-energy plant is a very high-tech plant whose emission impacts are negligible on air quality levels; results obtained also thanks to the choice of the sodium bicarbonate system for fume treatment.”
