Attention to the use of water resources

Water resources are used in industrial processes, such as the generation of electricity and thermal energy and composting processes, as well as clean sewage treatment plant tanks and anaerobic digestion tanks. Water is also used in small quantities for laboratory activity.
Group companies are committed to reducing drinking water withdrawals and implement measures to enable the use of recycled water. In this regard, there has been a gradual increase in the quantity of recovered water, from around 2.2 million m³ in 2021 to approximately 2.4 million m³ in 2022, an increase of 9%. Specifically, in 2022 certain companies in the water sector developed initiatives to reuse treated water. For example, at the treatment plans currently managed by Gori, treated wastewater was re-used. The wastewater used for this purpose, defined as “technical wastewater”, is distributed within plants through specific pipes and used for various purposes, including washing equipment (screens, units for thickening and drying of sludge), backwashing of certain parts of the treatment plant (membranes, fabric or sand filters), and washing of sand and screens. These sites are equipped with specific flow gauges, and water audits are conducted to assess water withdrawals and consumption from treatment processes and identify strategies to increase savings and reuse possibilities.
After having completed the industrial water network (non-drinking water) of the Roma Sud, Roma Nord, CoBIS and Ostia treatment plants in 2020-2021, Acea Ato 2 is planning similar actions at the Roma Est and Parco Leonardo (Fiumicino) treatment plants, increasing the amount of water intended for reuse according to a circular economy model. In 2022, the company recovered approximately 1.8 million m³ of process water, representing around 49% of total water used. At Acea Ato 5, around 535,000 m³ of treated water was used at the treatment plants for service activities related to their operation.
The Companies in the Environment sector limit the use of drinking water, mainly using water from wells. In addition, at the plants of San Vittore del Lazio, Orvieto, Aprilia, Monterotondo Marittimo and Terni, there are active systems for the recovery of rainwater. At the Terni plant, for example, rainwater is collected in two tanks equipped with a filtration system and storage tanks, before industrial use. The Aprilia composting plant also has a system for treating residual water from unprocessed waste, allowing it to be reused in production processes. For industrial uses²⁰⁷, such as vehicle washing, rainwater that has already been treated in the storage tanks through sedimentation and de-oiling is also reused. The Monterotondo Marittimo plant also has a rainfall recovery system that, after phytodepuration, enables collection of the water in special aerated reservoirs as a reserve for fire-fighting and as a reserve of industrial water for process use. At the waste-to-energy plant in San Vittore del Lazio, rainwater goes through a special chemical/physical treatment process to produce demineralised water, which is then entirely reused within the same system as part of a closed cycle, with no water discharge to the environment. Finally, the Orvieto plant hub collects rainwater from the roofs of certain buildings and transfers it to underground storage tanks serving the fire-fighting reserve. Thanks to the various solutions described, the volume of water recovered from the Environment Area was approximately 70,720 m³ in 2022.

Water withdrawals of the main Group companies associated with industrial processes and civil use are illustrated in Table no. 65. While withdrawals were generally stable during the year, the illustrated actions have led to a significant increase in the amount of re-used water during the three-year period²⁰⁸. The reuse of treated waste water is an effective response to water stress in Acea’s areas of operation, but specific regulatory interventions are required to further expand its potential. In this sense, the recent European Regulation 2020/741 on the reuse of treated water in agriculture, in addition to provisions that will be adopted with national regulations, facilitates a significant reuse of treated water in coming years.

Table no. 65 – Water withdrawal and recovery (2020-2022)

NOTE Intake of freshwater occurs in areas at potential risk of water stress, as defined by the Aqueduct Water Risk Atlas, the map drawn up by the World Resources Institute (WRI).
(*) The figures for the 2020-2021 two year period have been adjusted following consolidation.
(**) Water withdrawn for industrial use was partly used in processes totalling 0.193 Mm³ in 2020, 0.090 Mm³ in 2021 and 0.179 Mm³ in 2022; the discharge of water withdrawn for industrial use over the three-year period was 0.043 Mm3 in 2020, 0.027 Mm3 in 2021 and 0.001 Mm³ in 2022.
(***) The data refers to river withdrawals for the Orvieto Hub and sites managed by Deco.
(****) Water withdrawn for civil/sanitary use from aqueducts, representing 99.9% of total withdrawal for this purpose, is discharged into the public sewerage system after reuse and returned to the environment.
(*****) Out of the total water withdrawn, water consumption in the three-year period was 10% in 2020, 8% in 2021 and 12% in 2022. The increase in 2022 is partly attributable to the inclusion of Deco in the reporting scope.

The Group promotes informed and careful use of water resources, also throughout the supply chain, raising awareness among suppliers through issue of a questionnaire (see also the sub-section Energy consumption along the supply chain).

Discharges of water intake occur within authorised and closely controlled processes. For example, at the Terni waste-to-energy plant, residual water from production processes is first treated by internal treatment plants, before being discharged into public sewerage. Water used in the waste-to-energy process at the San Vittore del Lazio plant, instead, is collected and stored in special underground tanks and disposed of as waste, as it may contain components that make it unsuitable for normal discharge. Wastewater from toilet facilities on the production lines and at the relevant offices is collected in septic tanks and subsequently disposed of, while the sewage from the administration building is collected and conveyed to an Imhoff tank with a sub-irrigation system for subsurface clarification. Water intake for industrial uses in activities connected to the integrated water service, and in particular water treatment, undergoes the same treatment as waters transported via public sewerage, i.e. it is retreated at the head of the treatment plant and sent to the locations described in the section Sewerage service and treatment system, in the chapter Water segment. All civil water intake from the aqueduct ends up directly in the sewer network.

207 In 2022, the existing plant underwent a major energy eciency upgrade, which caused a period of plant downtime, with a resulting temporary reduction in water production from the reverse osmosis plant.
208 The increase is partly due to improved measurement processes.