Advanced oxidation processes (AOPs) have emerged as effective solutions for treating wastewater containing persistent and harmful pollutants. This book explores the principles, mechanisms, and applications of AOPs in wastewater treatment. Topics include the use of photocatalysis, ozonation, and Fenton reactions in degrading contaminants. Students and professionals will critically analyze the advantages, limitations, and real-world applications of AOPs. The book provides evidence-based insights into designing sustainable treatment systems for water quality improvement.