This book offers a comprehensive exploration of cross-scale technological innovations for diagnosing, mitigating, and sustainably managing aquatic contamination across natural and engineered water systems. The chapters integrate biological, chemical, physical, and digital approaches, spanning advanced bioremediation, wastewater purification, ecological restoration, and environmental monitoring. Contributions examine treatment technologies such as constructed wetlands, membrane distillation, adsorption materials, catalytic degradation, ultrasonic photocatalysis, and integrated multi-process recycling for industrial and municipal wastewater. Several studies investigate sediment remediation, nutrient immobilization, PFAS and heavy-metal control, oilfield and mining effluents, and emerging nuclear wastewater challenges, while others analyze plankton communities, bioindicators, and ecosystem health assessment in rivers, estuaries, and protected areas. Beyond treatment processes, the volume highlights intelligent sensing and modeling methods, including IoT-enabled monitoring, carbon nanotube biosensors, hydro-environmental simulations, digital twins, and early-warning systems for water quality and aquaculture safety. Climate-hydrology interactions, precipitation variability, water resource allocation, and carbon emission accounting are also addressed to link watershed management with broader sustainability goals. By connecting laboratory mechanisms, pilot engineering, field ecology, and decision-support modeling, the book demonstrates how integrated technologies can transform contamination control into adaptive ecosystem stewardship. This volume is intended for environmental engineers, water resource managers, environmental scientists, policymakers, and graduate students working in aquatic pollution control, ecological restoration, and sustainable environmental technology development.
