Attention to the use of water resources

[GRI - 103-1], [GRI - 103-3], [GRI - 303-1], [GRI - 303-2], [GRI - 303-3], [GRI - 303-4], [GRI - 303-5],

The main water intake of the Group is related to production processes, such as the production of thermal energy at the Tor di Valle plant, that of electrical energy at the waste-to-energy plants and the production of compost. Water resources are also used for cleaning of units in treatment plants, backwashing fine grilles and anaerobic digestion units. Water is also used in small quantities for laboratory activity.

While in 2020 accounting for industrial and civil water usage, including reuse, was greatly improved, in 2021 the increase in the  portion recovered, approximately 2.2 million m3 (515,000 m3 in 2020) led to lower consumption of drinking water. Some Companies in the water sector launched specific projects and actions for reuse of treated water (see the box on reuse of water used for technical purposes by GORI). 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.

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 outside of the Group).


At the treatment plants currently managed by GORI there is reuse of treated effluents for usage within the plant itself. The wastewater reused, defined as “for technical purposes”, 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. The quantities of water used for these activities are not currently measured. In 2022, a monitoring programme will be launched for all uses of water for services within the treatment plants, including activities carried out using water for technical purposes as previously de- scribed, and other uses (cooling, irrigation of green areas, fire-protection uses, toilets, etc.) that are currently carried out with drink- ing water. Through installation of specific flow meters, the goal is to implement a water-audit methodology that enables assessment of the water footprint for treatment processes and identification of strategies for greater savings and reuse of water within the individual plants. Reuse of treated wastewater is an effective response to water stress which also affects the territorial area managed by GORI.

In order to reuse water from treatment processes and minimise consumption of drinking water, in the period 2020-2021, the Company Acea Ato 2 completed the industrial water network (non-drinking water) for the treatment plants of Roma Sud, Roma Nord, Cobis and Ostia. In the period 2022-2023, there are plans for expansion of the industrial water network for the Roma Est treatment plant, as well as for the launch of similar works at the Parco Leonardo treatment plant (Fiumicino), increasing the quantity of water reused with a circular-economy approach.

The works described have enabled a reduction in the quantity of drinking water used for industrial processes, also impacting the figure for the Group. In fact, in 2021 (see Table no. 64), total water consumption, excluding water recovered, was down 7%.

Not all Companies have been successful in obtaining authorisations for reuse: in 2021, Acea Ato 5 submitted a plan to the Area Authority for the reuse of wastewater discharged by certain treatment plants, included in the Plan of Works, selected on the basis of the potential reusers.

Excluding the plants with capacity below 2,000 Population Equivalent, with dimensions too small to guarantee constant provision to potential reusers, assessment was carried out within the scope of plants for which adaptation/upgrading works are already set out under the current Plan of Works. This assessment identified a single plant located in the municipality of Pontecorvo and situated near large agricultural companies/land-improvement cooperatives that could benefit from reuse of the treated water. However, analysis of overall costs and works time frames led to its feasibility being excluded.

The Companies in the Environment Segment limit the consumption 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 the treatment of residual water from waste awaiting processing for reuse in production processes, and only for industrial uses (e.g. washing vehicles). Other water reused for industrial purposes, since 2021, has been obtained from the evaporation line for liquid digested material. At the Monterotondo Marittimo, plant, in order to reduce water consumption aimed at greater consolidation and safeguarding of resources, there is a recovery system for rainfall that, after constructed-wetland treatment, enables collection of the water in special aerated lagoons, both as a reserve for fire-fighting and as a reserve of industrial water for process use. In December 2021, works were also completed for the creation of new fire-fighting tanks that allow allocation of the recovered water reserve only for industrial use within the site. At the San Vittore del Lazio waste-to-energy plant, every year rainwater is used in the production of demineralised water, after treatment in a specific chemical-physical plant, and is completely reused in the process. There is therefore zero discharge. Finally, the Orvieto plant hub collects rainwater from the roofs of some buildings, channelling it into the fire-fighting tank serving the building where compost maturation and storage phases take place. Thanks various solutions described, the volume of water recovered from the Environment Segment was approximately 47,700 m3.

Attention to management and consumption of water is also high- lighted by the Piaggio Reuse project, led by Acque Industriali (see specific info. box).


Piaggio Reuse is a project led by Acque Industriali aimed at establishing a circular water management model at the Pontedera plant complex, in the province of Pisa. Currently co-existing at the Pontedera complex are the chemical and physical treatment plant of the Piaggio plant, the civil wastewater treatment plant of Acque SpA and the industrial wastewater treatment plant of Acque Industriali, which primarily processes effluents from the Piaggio plant. The project involves a qualitative increase in water leaving the wastewater treatment plant, through creation of a biological post-treatment phase using MBR (Membrane Bio Reactor) technology that generates a flow of water for reuse within the production cycle and brings a consequent drastic reduction, or complete elimination, of water drawn from groundwater resources. A similar effect is expected on the volumes of water discharged, with lower environ- mental and economic costs. The project began in 2021 with an initial step in the form of a pilot project, and will be extended in 2022 to the full-scale plant. The results of the project could be replicated on all industrial plants with very high water consumption.

Group water intake associated with industrial processes and civil uses is presented in Table no. 64.

Table no. 64 – Water intake of the main Group Companies (2019-2021)

type of intake

2019 (*) 2020 2021

industrial processes (district heating, thermoelectric generation, Ambiente plants, Water companies)

0,38 0,851 2,419

of which aqueduct (*)

0,237 0,229 0,108

of which well

0,092 0,104 0,105

of which river water (**)

0,003 0,003 0,003

of which recovered water

0,048 0,515 2,202

water consumption for civil use (***)

2,079 2,615 2,533

total water consumption

2,459 3,466 4,952

total water consumption excluding recovered water

2,411 2,951 2,749

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). (*) This item includes water transported by tankers to the Aprilia site (7,580 m3 in 2021).
(**) Consumption refers exclusively to the withdrawal from the Paglia river near the Orvieto composting plant.
(***) Civil consumption derives from: aqueduct (99.9%), well and tankers.


Since 2020, to raise awareness along the supply chain of the importance of safeguarding water resources, the Sustainability Planning & Reporting Unit, with the support of the Procurement and Logistics function, has sent a panel of suppliers (on an experimental basis) a request for environmental data including information on water intake, divided by process and civil uses. 40 suppliers out of 100 suppliers invited to replied to the section on water resources, corresponding 42% of the total expenditure of the Acea Group for procurements of goods, services and labour. Water intake for the above suppliers in 2021 equalled approximately 10,750 m3, divided into 7,050 m3 for industrial uses and 3,700 m3 for civil uses. Acea intends to continue with this request in the coming years as well, improving data collection and continuing to raise awareness on this issue.

Discharges of water intake occur within authorised and closely con- trolled 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 of production lines and offices are collected in septic tanks and subsequently sent for disposal. Sewage from the headquarters is instead collected and transferred in an “Imhoff tank” with a sub-irrigation system for clarified material into the soil. Rainwater is reused in the production of demineralised water, after treatment in a specific chemical-physical plant, without external discharge.

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 public sewer system.