Health and Environmental Risk Management Planning for Water Reuse in Railway Construction Sites: a case study.

The increasing pressures on natural water resources are causing water scarcity and a deterioration in water quality. Climate change and unpredictable weather conditions are significantly contributing to the depletion of freshwater reserves due to agriculture and urban development. This situation calls for sustainable management of natural resources and a transition towards a circular economy. In this regard, the European Union issued Regulation (EU) 2020/741 of the European Parliament and of the Council on 25 May 2020, establishing minimum requirements for water reuse. In Italy, the issue of treated wastewater reuse is regulated by D. Lgs. 39/2023, converted with amendments by Law 68/2023, as well as by D.M. 185/2003, both referring to reuse for irrigation. In the territory of the Sicily region, to counter water scarcity, an implementing decree was approved—D.A. no. 6/GAB of 6 February 2024—under Regional Law 22 March 2022, no. 4 “Rules on the reuse of urban treated wastewater, amendments to Regional Law 29 July 2021, no. 20.” This decree regulates, as relevant here, the reuse of refined urban wastewater for irrigation in agriculture, as well as for civil, industrial, and environmental/recreational uses. This thesis develops a risk management plan—both sanitary and environmental—specific to the industrial reuse of treated wastewater, applied to the treatment plant of Termini Imerese (PA), whose water will be destined for use in construction sites for the tunnels of the new Palermo–Catania railway connection. The industrial reuse of treated wastewater is an innovative circular use; for this reason, a risk management plan has been developed specifically for this type of reuse. Reference was made to the Joint Research Centre (JRC), the scientific service of the European Commission, in their technical report “Technical guidelines for risk management of water reuse in agricultural irrigation systems in Europe,” which was adapted for industrial reuse. As required by Regulation (EU) 2020/741, the risk management plan adopts a systematic approach based on a structured analysis of the water reuse system, identification of potential hazards and hazardous events (as well as populations and environments at risk and exposure pathways), and, where necessary, the planning of preventive measures and barriers to manage and mitigate the identified risks. It also includes provisions for communication and cooperation among the involved parties, to ensure corrective actions are adopted and notified. The key elements of risk management (KRM) aim to guarantee that refined water is used and managed safely to protect human and animal health and the environment. These elements are organized into four modules to facilitate the drafting of the management plan. The core tool of the plan is the risk matrix, which analyses and synthesizes all potential risks and hazards, the countermeasures already in place, and provides further solutions to reduce probabilities where needed. Semi-quantitative methods were utilized to calculate risk, and support for risk definition was provided by FMEA analysis and check of compliance with regulatory limits. In the case examined in this thesis, it was necessary to develop four matrices: two related to health risk and one to environmental risk. Regarding the health risk, two separate matrices have been developed: one for the treatment plant and one for the distribution network. For the industrial reuse of water from the Termini Imerese treatment plant, no significant critical issues were detected; moreover, the measures already adopted or planned are adequate in most cases. However, to ensure health and environmental well-being, it was necessary to implement specific protocols to be followed during reuse, such as: communication procedures among the involved parties to ensure timely reporting of any non-compliance or supply interruptions; Training programs for workers.