This book aims to be the preeminent university chemistry textbook for environmental engineers. It provides undergraduate and graduate environmental engineering students with basic concepts and practical knowledge about chemistry that they would need in their professional careers. It focuses on the fundamental concepts of chemistry and its practical applications (e.g., understanding fate and transport of chemicals/pollutants in the environmental as well as the chemical/physicochemical processes applied in environmental engineering industry). This book also serves as a valuable resource for entry-level professionals to solidify their fundamental knowledge in environmental engineering chemistry. This book Presents the fundamentals of chemistry with focus on the needs of environmental engineers. Explains how an understanding of chemistry allows readers a better understanding of the fate and transport of chemicals in the environment as well as various treatment processes. Examines the fundamentals of chemical reaction equilibrium from learning the basics of thermodynamics. Presents the basic types and designs of reactors as well as reaction kinetics.