Water quality

As shown in Chart no. 55, water quality is monitored by companies in the Water Business. The analytical checks, in addition to those performed by the Local Water Authorities, are performed on a scheduled, ongoing basis and regard drinking water supplied to users, essential due to the associated health effects, and water returned to the environment following treatment, both of which are functional to monitoring the environmental quality of the region. Compliance with drinking water analyses for all companies within the scope of reporting is between 96% and 100%.

Chart no. 55 – Analytical checks on drinking water, total and by company (2023)

In Rome, the qualitative characteristics of the resource collected and distributed are monitored through continuous testing, with instruments located along the water systems and through daily sampling at the collection points and in the distribution network. In Lazio, there are certain volcanic areas where groundwater contains mineral elements, such as fluoride, arsenic and vanadium in concentrations higher than permitted by law. In these areas, for some time, Acea Ato 2 has been working to resolve these issues, such as by decommissioning some local sources of supply and replacing them with higher quality springs. In 2022-2023, in particular, Acea Ato 2 built new drinking water plants and upgraded/expanded existing plants in the municipalities of Allumiere, Ariccia, Rignano Flaminio, Manziana.

Monitoring of the chemical-biological parameters of the water in the distribution network of the water system allows a high quality and safety level to be achieved. Overall in 2023, 419,940 analyses were conducted in the area managed by OTA 2, for a total of 14,412 samples ofdrinking water. In addition to the analyses conducted to check water quality, performed by Acea Ato 2, with the support of Acea Infrastructure, analyses were performed by Acea Infrastructure for study and research purposes aimed at continuous improvement of monitoring of the drinking-water system.

Acea Infrastructure, accredited pursuant to the ISO/IEC 17025 standard²¹⁷, performs and certifies chemical and microbiological analyses in different substrates, including water (see Table no. 59 for the analyses performed on Rome drinking water). AdF, which outsources analyses to Acqua SpA, took 3,841 samples in 2023, identifying representative withdrawal points in the context of districts, with equivalent characteristics, into which the entire network of the aqueduct is divided. All withdrawal points are georeferenced using the GPS system and area available in a WebGis. Furthermore, having launched its own analysis laboratory last year, the internalisation of its wastewater samples was completed in 2023 and accreditation for the main testing methods was obtained, which was applied to the water matrices intended for human consumption.

Table no. 59 – Analytical determinations in Rome (2021-2023) and main quality parameters of the drinking water distributed in Lazio, in Campania and in Tuscany 2023)

(*) In accordance with Legislative Decree no. 18/23 and in agreement with the health authority, Gesesa is exempted from supplying the parameter.

In 2023, Gesesa continued a project for the creation of an activated-carbon filtration system for treatment of drinking water for the water plant in Benevento, in the Pezzapiana area²¹⁸.
With regard to the processing of drinking water, at the Grottarossa and Montanciano plants of Acea Ato 2, monitoring and analysis activity continued on treatment processes (such as chemical conditioning and pre-oxidisation, clariflocculation, sand filtration, and others), evaluating the efficiency of the removal of pollutants, specialised parameters for emerging organic species, both microbiological and sub-products of disinfection, in relation to the main management parameters of the plant. In addition, with reference to forecasting the availability of water resources, during 2023 Acea Ato 2 implemented and continued to develop a machine learning algorithm to identify meteorological proxies (temperature and/or precipitation) or management proxies (volumes drawn) correlated to the variability of the state of preservation of the resource, with reference to the different collection sources (springs, well fields, etc.) In addition to scheduled checks, the water companies also carry out extraordinary checking, on the request of utilities, Local Health Authorities (ASL) etc., to monitor specific parameters like radioactivity and PFAS (poly and perfluoroalkyl compounds). In 2023, as happened in the previous two-year period, Acea Ato 2 and Acea Ato 5 subscribed to the campaign launched by the Lazio Region to monitor and check radioactivity in water intended for human consumption.

217 In February 2023, the laboratory was successful in renewing its accreditation pursuant to UNI CEI EN ISO/IEC 17025:2018. The nexti nspection is scheduled for January 2024.
218 The filtration plant will provide adequate water resources for the city of Benevento, maintaining the values for the substances tetrachloroethylene and trichloroethylene below the Contamination Concentration Limits (CCL) defined by Italian Legislative Decree 152/2006.