Hera Group acquires Sostelia: important synergies for Herambiente in industrial water treatment

Today Hera Group signed the binding agreement for the purchase of 100% of STA and the related stakes in the subsidiaries that are part of the Sostelia Group (NTW, CID, NPC, Trentino Acque, COMS, Acque della Concordia, Arcobaleno GC). Sostelia is an important Italian private player for technologies and the treatment of industrial and civil water, 65% controlled by Xenon Fidec, an impact private equity fund managed by Xenon AIFM, and with the remaining 35% held by entrepreneurs representing the companies within the group.

The acquisition by Hera Group is subject to certain customary closing conditions (including notifications and approvals by the competent authorities) and is expected to be completed by the end of March 2026.

The transaction has an enterprise value of €138 million. Once fully integrated, the transaction is estimated to contribute more than €20 million to the consolidated EBITDA growth of Hera Group, in addition to the value of the expected integration synergies.

The strategic lines of the transaction

The transaction creates a benchmark player in Italy with an integrated offering in the water treatment market - from design and construction (EPC) to operation and maintenance (O&M), up to the treatment and disposal of liquid waste and sludge related to purification processes. It also enables a strong system of synergies with Herambiente, enhancing quality, efficiency, and service continuity for both public and private customers.

Synergies are, in fact, one of the main drivers of value creation. On the one hand, the integration of Sostelia’s services could enable Herambiente to broaden its commercial offering by providing its customers with additional services such as revamping solutions and the design of new plants, or the operation and maintenance of existing private plants, ensuring technical-operational continuity that translates into greater reliability and lower operating costs. On the other hand, Sostelia’s customer portfolio represents a significant opportunity for Herambiente to integrate its own service offering.

Among the key elements underpinning the industrial synergy of the acquisition, the know-how developed by Sostelia and Hera Group in the integrated water cycle - both civil and industrial - also stands out. Hera Group can already boast many years of experience deriving from the direct management of dozens of owned plants dedicated to civil wastewater treatment in the served territories and to the treatment of liquids from industrial waste. For its part, Sostelia also provides integrated services and cutting-edge technologies for the treatment of industrial wastewater and sludge, for water resource recovery, and to address the new challenges linked to the recent EU Directive 2024/3019, which introduces stricter obligations on the treatment of urban wastewater. An example is solutions for PFAS abatement, aimed at reducing the environmental impact of these pollutants.

More generally, the combination of Sostelia’s technical expertise, plant infrastructure, and commercial capability will enable Hera Group to expand its customer base, diversify revenues, and increase business resilience in a sector that requires speed of intervention, high quality of service, and continuous innovation.

The Sostelia Group in figures

The Sostelia Group has a base of over 1,200 plants under management, more than 1,200 active customers, around 350 employees, and its economic and financial profile confirms the industrial solidity of the transaction. About 70% of the activity is focused on industrial customers; in terms of business lines, about half of revenues comes from water treatment solutions - an essential gateway to long-term management and maintenance contracts - while the remaining part comes from ancillary services. Commercial diversification is broad, with a portfolio that combines large industrial players in the private market and significant public contracts in the municipal segment and, geographically, strong coverage of Northern Italy and an already established international presence that generates about 10% of revenues. The company also has a direct presence in waste treatment, thanks to an advanced liquid waste treatment plant in Casalmaggiore (Cremona) complementary to Herambiente’s plant network.