Enhancing energy efficiency in Mediterranean wastewater treatment plants: An environmental assessment

Wastewater treatment plants (WWTPs) play a crucial role in ensuring the availability of water, a key and increasingly scarce resource in the Mediterranean region. These facilities are essential for enhancing climate resilience in local communities, yet they are also characterized by high energy demands. This study aims to model the energy and environmental performance of the novel PROGRAMOX® technology aimed at increasing the energy self-sufficiency of WWTPs. A life cycle assessment of a representative WWTP in the Mediterranean was conducted to compare a conventional treatment train (i.e., Conventional Activated Sludge) with the implementation of PROGRAMOX®. A full-scale theoretical scenario using pilot-scale data was modelled through mass and energy balances. Results suggest that the PROGRAMOX® configuration can reduce total electricity consumption by 15% as well the associated environmental impacts as Global Warming, Fossil Resource Scarcity and Cumulative Energy Demand categories by 5%, 29% and 51%, respectively. As result, it also increases biogas production for self-consumption by more than 50%. However, the anaerobic digestion and the cogeneration unit generate trade-offs in other impact categories because of their low conversion efficiencies. Our study highlights the potential benefits of testing and implementing this technology in Mediterranean countries with carbon-intensive electricity mixes, as it can reduce their environmental impacts by more than 30% in many categories. Future studies shall validate this model with real operational data applied to different locations.