Management and minimisation of waste produced

All Group Companies contribute to an overall reduction in the quantity of waste, in line with circular-economy principles. Acea Produzione produces a minimal quantity of waste (approximately 774 t in 2021), promoting recovery and recycling where possible. The water companies have projects underway aimed at reducing the volume of sludge, for example by implementing new dryer lines, centrifuges and other specific systems. This approach represents a great impact in terms of the circular economy: a reduction in the percentage of water in sludge guarantees the opportunity for material and/or energy use or disposal with lower costs.
In 2021, in addition to taking over various regional plants, GORI changed supplier assigned to recovery and disposal and, for the first time, 65% of sludge produced was recovered and sent for composting (in 2020 1% of sludge was recovered). At AdF, in order to reduce the quantity of sludge deriving from the water-treatment process, a new Newlisi section was installed at the San Giovanni treatment plant in Grosseto, with the goal of treating dewatered sludge produced in the other plants, reducing the overall quantity. Since 2017, Acea Ato 2 has defined and implemented the “Sludge Management Plan”. This contains structural and strategic actions with the dual objective of reducing volumes of treatment sludge produced and exploiting the solid components both as a material and for energy, through a range of different actions, rationalising the entire treatment segment and transforming large treatment plants into hubs for centralised sludge processing. In order to reduce the volumes of waste, Acea Ato 5 is planning the installation of a sludge drying system at the Fiuggi - Colle delle Mele treatment plant. In 2021, the various design alternatives were assessed. Overall, 67% of sludge was recovered for the Water Segment, corresponding to 102,760 tonnes.
At the Aprilia and Monterotondo Marittimo composting plants a new plant configuration has been operational since 2019, which enables energy recovery through anaerobic digestion. At the Aprilia plant, with issue of the new EIA, obtained in January 2021, various actions will be implemented, including construction of a new line for production of SRF from plant waste.
Waste from the majority of Group Companies is sent to an external site¹⁶⁹. Finally, for all Companies, waste is managed by companies outside the Group, with the exception of Acea Ato 2, Acea Ato 5 and AdF, which, as mentioned, handover their waste to Aquaser, in the role of broker with identification of final-destination sites¹⁷⁰. The reliability of brokers in general is guaranteed by the mandatory authorisation required by the specific regulations for performance of activities and by periodic checks on documentation.
The data and information on waste for the main Companies is managed with dedicated management software171.¹⁷¹.
Quantitative data on waste disposed of derives from direct measurements taken using weighing systems, which are periodically calibrated and certified. For the Companies of the Environment Segment, in almost all cases there is a difference between the outgoing weights and incoming weights, due to the scales used for approximation in the systems adopted, in any case documented using the forms applicable by law. In addition, for these Companies and for Acea Produzione, which are equipped with plants mainly certified in accordance with standard UNI EN ISO 14001, systematic checks are carried out on legislative compliance of compliance in terms of environmental factors.
In 2021, there were no significant releases of pollutants into the environment, such as mineral oils, fuels or chemical products¹⁷².

¹⁶⁹The only exception is the Orvieto plant, which is classed as a plant hub and therefore has waste streams with internal final destinations.
¹⁷⁰Liquid waste from the plants of Acea Ato 2 are assigned to Aquaser solely for logistical services, being transported and discharged at plants authorised pursuant to art. 110 of Italian Legislative Decree 152/2006 managed by Acea Ato 2 itself.
¹⁷¹With the exception of Gesesa and Areti, all companies have dedicated management software.
¹⁷²At the Area Nolana treatment plant (GORI) in 2021 there was a spillage of ferric chloride, used for conditioning of sludge, which was appropriately confined within sealed containment channels without affecting the environment.