Converting a large industrial plant is never simple, both in economic and environmental terms. The challenge is made all the more difficult when the structure in question is an incinerator in a highly urbanised area, just a few miles away from homes and schools. In a case such as this, direct consultation with the public is a vital step. 

This is the path followed by Gruppo CAP in Sesto San Giovanni, a municipality on the outskirts of Milan. The company, which manages the integrated water services for the Metropolitan City of Milan, is carrying out the transformation of an incinerator that has reached the end of its lifecycle and is scheduled to be closed next year. The operation involves the Energy Recovery Consortium (Core SPA), which manages the disposal of solid urban waste in Sesto, Cologno Monzese, Pioltello, Segrate and Cormano, as well as each municipality’s councils, that are all partners of the energy recovery consortium, CORE. 

CAP and CORE opted for a plan to profoundly transform the area, turning it into a state-of-the-art waste management hub to enhance the circular economy. Local citizens were involved in public debates to collect suggestions and proposals for the project, which involves a symbiotic industrial relationship between incinerator and purification plant. The goal is to create a bioplatform dedicated to circular economy, carbon neutrality and zero emissions.

The incinerator – owned by CORE – currently employs 43 people. It is located in the proximity of a purification plant that treats industrial and civil sewage from Sesto San Giovanni, with a service capacity equivalent to 124,000 residents (the city counts 81,000). The project involves uniting the two plants to form a single, publicly-owned site. Compared with the current structure, the aim is to reduce the emission of noxious fumes by 76% and completely suppress climate altering molecules. 

The new bioplatform will be structured along two lines. Respectively, these will treat sewage from the Councils that are part of CORE and wastewater derived from Gruppo CAP’s purification plants. The plant, according to figures provided by the company, will process 65,000 tonnes per year of wet waste (equal to just over 14,000 tonnes of dried sewage). Three quarters of these will be used to generate district heating, with a yearly output of 11,120MWh. The remaining 25% will be turned into phosphorus to be used as fertiliser, while the purified water will be reintroduced in the Lambro river or used for irrigation in parks in the surrounding area. The Council’s wet waste treatment line (Forsu), on the other hand, will process 30,000 tonnes of material per year, which will be used to produce biomethane. 

CAP have invested over 47 million euro in this ambitious reconversion plan. Company documents state that the goal is to create “a true hub of green innovation, at the heart of the metropolitan network of purification plants managed by the Group, for experimentation on wastewater.” The project also avails itself of the collaboration with partners of the Smart Plant Project, funded by the EU within the framework of the Horizon 2020 objectives. These include Verona University, Milan’s Politecnico, Bicocca University, and CNR (Italy’s National Research Council). The area is destined to “host researchers and start-ups involved in the development of new eco-compatible solutions, to transform what used to be waste into products with high added value. A true green ‘biorefinery’ that will generate biomethane and heat, recover nutrients and produce compost, bioplastics and natural fertilisers.”

Alessandro Russo, President and CEO of CAP, explains that the bioplatform “is a unique project in Italy. It abandons the logic of linearity and pursues sustainable circularity, focusing on ecodesign, recovery of waste materials and the industrial redesign of products and processes. It will be the result of a structured, cross-sectorial path that puts citizens, local committees and associations at the centre of the planning process.”

Because of its importance and the significant impact it will have on the surrounding area, the five Councils have opted to involve citizens as much as possible from the very beginning. Special efforts were made to include those who would normally not get the chance to express themselves in institutional settings. This approach was shared by CAP and CORE, which led to the creation of the “BioPiattaformaLab” collaborative pathway. 

Inspired by the French débat public model, the process was assigned to the Nimby Forum. This think tank specialises in the “not in my backyard” syndrome and it has been part of over 50 collaborative processes throughout Italy since its founding in 2004, with the goal of creating consensus about industrial initiatives. 

The process of citizen participation involved five meetings that were open to the public and took place between November 2018 and January 2019. Concurrently, documents related to the various steps of the process and FAQs were published on the BioPiattaformaLab website.

During the first four meetings, the general characteristics and some specific features of the new plant project were presented, highlighting its peculiarities and the impact it would have on the territory. Citizens, as part of working groups, were able to establish the details about which they required more information and input from experts. Observations were collected and summarised in a report that was presented at an open meeting in April. 

Overall, 89 economic, administrative and environmental observations were evaluated in the following months. Technicians from CAP and CORE provided feedback to each one, which was presented in a meeting at the beginning of April. Thirty of these were added to the call for tender for the creation of a definitive project for the plant. They included the insertion of sustainable urban drainage solutions that favour the retention and filtration of rainwater, as well as a preliminary risk assessment, with changes to the project to ensure the functioning of the bioplatform in the case of flooding from the Lambro river. 

The contract was won by Swiss company Tbf + Partner AG, a leading energy engineering firm that specialises in the thermal enhancement of purification muds. The delivery of the project is expected by the end of November. After this, the regional bureaucratic approval process (PAUR) will begin, which will include an environmental impact evaluation and the drafting of a call for tender for the works.

Meanwhile, the participative process has continued. July saw the beginning of a path that, by the end of the year, will lead to the creation of the Residential Advisory Board (RAB). This committee, requested by citizens during the meetings last winter, will control and monitor the works. This model, used for the first time in the Netherlands, has spread to Italy in recent years, for example for the incinerator in Ferrara and the wastewater treatment plant at Bassano del Grappa. The consulting body, made up of representatives from companies, public authorities, citizens and committees, will have the task of following the advancement of the project step by step, offering opinions, ensuring the transparency of information available to citizens and facilitating interactions between residents and the company performing the works.  


Gruppo Cap,

Consorzio recuperi energetici,

Nimby Forum,


Tbf + Partner Ag,