USE OF ENERGY AND PROCESS INDICATORS TO IMPROVE THE PERFORMANCE OF WASTEWATER TREATMENT PLANTS

Water is a vital resource, essential for human health, environmental sustainability, and economic development. By 2050, global water demand is projected to increase by 20-30% due to population growth, necessitating enhanced resilience in water management, especially in water-scarce regions. Wastewater treatment plants (WWTPs) play a crucial role in mitigating these issues by employing physical, chemical, and biological processes to remove contaminants from wastewater before its release into the environment. Industrial wastewater, particularly from large industries such as food and textile sectors, significantly contributes to water pollution, necessitating advanced treatment solutions. WWTPs follow a multi-stage treatment process that includes preliminary, primary, secondary, tertiary treatments, and disinfection to ensure treated water meets environmental standards. However, the energy-intensive nature of WWTPs contributes substantially to greenhouse gas emissions, emphasizing the need for energy-efficient treatment methods. The adoption of anaerobic digestion and advanced aeration techniques can enhance energy efficiency and reduce the carbon footprint of WWTPs. Improving the efficiency and adaptability of these systems is a key priority. Furthermore, challenges such as emerging contaminants, stricter regulatory standards, and the impacts of climate change, including water scarcity and variations in wastewater composition, add complexity to WWTP operations. Addressing these challenges necessitates the integration of innovative approaches that improve both energy efficiency and treatment capabilities. Circular economy models, focused on resource optimization, are driving investments in green technologies, which are essential for combating climate change and ensuring sustainable water management. In Italy, the Recovery and Resilience Plan prioritizes water resource protection and efficient service management. Strengthening data infrastructure and governance frameworks is essential for effective water management and policy implementation. The EU Water Framework Directive (WFD, 2000/60/EC) provides a comprehensive framework for sustainable water management, aiming to ensure high-quality water access and ecological protection. This thesis investigates the use of energy indicators to evaluate WWTP performance, aiming to enhance sustainability by balancing environmental protection with energy efficiency. By analyzing energy consumption and efficiency through various methodologies, the study contributes to the development of sustainable wastewater treatment solutions that address both ecological and operational challenges. The first part of the research is based on an overview of the methodologies applied for energy efficiency and performances utilized in WWTPs. It is followed by the benchmarking of plants through key performance indicators for energy consumption, and an evaluation of operation and consumption of each stage of plants. It gives a general overview of all plants' energy consumption and utilization of all energy for each stage, for each group dimension size and technology. The next step is followed by the methodology of class performances of the plants based on two indicators, the energy performance indicators and removal efficiency. This methodology gives an overview of the class performances of plants such as for example the class ‘A’, ‘B’, ‘C’, and ‘D’, for each parameter such as BOD, COD, TN, and TSS. A comparison of class performance is conducted between plants that include deodorization stages and those that do not. The other part of the research is followed by another methodology of Total Oxygen Demand which shows the performances of plants based on the consumption of oxygen which is one of the most energy-consumable parts of the plant. And in the last part, the evaluation of plants is carried out using a single Water Treatment Energy Index, which integrates all previously mentioned aspects. This index accounts for the total energy consumption at each stage, including the use of chemicals and any renewable energy sources consumed or generated. Through this analysis is provided a foundation for guiding energy audits and efficiency improvements in WWTPs, which is crucial in addressing the growing global emphasis on sustainable energy use in industrial operations.