Topic: Digital Transformation in Water Treatment: Sustainable Pathways from Wastewater to Energy

The water sector is entering a period of profound transformation, driven by the twin imperatives of sustainability and technological innovation. As global freshwater demand continues to rise and wastewater volumes increase, traditional treatment infrastructures are struggling to meet environmental, economic, and societal expectations. At the same time, the concept of wastewater is evolving from being perceived solely as a liability to being recognized as a valuable resource for energy recovery, nutrient recycling, and circular economy integration. To realize this paradigm shift, digital transformation has emerged as a central enabler, offering novel opportunities to optimize treatment processes, reduce operational costs, and enhance environmental performance.

Digital tools such as artificial intelligence (AI), machine learning, digital twins, big data analytics, and Internet of Things (IoT)-enabled monitoring systems are increasingly being applied to wastewater management. These technologies facilitate real-time process optimization, predictive maintenance, dynamic energy balancing, and adaptive resource recovery strategies, making it possible to reimagine wastewater treatment plants as integrated water-energy hubs. Furthermore, the convergence of digitalization with Industry 4.0 and the emerging Industry 5.0 paradigm opens pathways to not only enhance efficiency but also embed resilience, social responsibility, and human-centric values into water infrastructure.

This special issue “Digital Transformation in Water Treatment: Sustainable Pathways from Wastewater to Energy” seeks to highlight cutting-edge research, technological innovations, and policy frameworks that are shaping the future of digitalized water treatment. It brings together interdisciplinary perspectives ranging from advanced sensor development and process control to resource recovery systems and life-cycle assessments. By focusing on the nexus of water, energy, and digital technologies, this collection aims to inform scientists, practitioners, and policymakers about scalable pathways to achieve sustainability goals, align with global climate and circular economy agendas, and advance the transition toward smart and carbon-neutral water systems.

Digital transformation; Wastewater treatment; Water-energy nexus; Circular economy; Artificial intelligence (AI); Machine learning (ML); Digital twins; Big data analytics; Internet of Things (IoT); Smart water systems; Predictive maintenance; Process optimization; Resource recovery; Energy recovery from wastewater; Carbon neutrality; Industry 4.0; Industry 5.0; Life-cycle assessment (LCA); Digitalization