This book provides comprehensive coverage of the fundamental principles and current practices in water processing, water distribution, wastewater collection, wastewater treatment, sludge processing, advanced wastewater treatment and water reuse, along with an understanding of sustainability. This seventh edition updates the subject matter, illustrations, and problems to incorporate new concepts and issues related to the water environment. This edition introduces the issues of water supply and water sustainability in chapter 1 as a backdrop to the issues of water and wastewater treatment and ends in chapter 15 with a critical focus on energy sustainability and carbon footprint. In addition, the revision focuses on energy reduction opportunities, optimization and processes important to sustainability such as membrane biological reactors and ultraviolet disinfection. Extensive use of illustrations in the book provide better understanding of the concepts and show modern equipment and facility. The book is appropriate for undergraduate level civil engineering courses in environmental engineering/technology, water supply and sanitation and water quality control, and environmental studies.