The eighth edition has been modernized and its coverage of topics expanded to meet the contemporary needs of students and practitioners concerned with water supply and pollution control. The book is also intended to meet the needs of upper division undergraduate students, beginning graduate students, and practitioners in civil and environmental engineering. The book's tradition ofr presenting treatment processes in the context of what they can do, rather than in the context of water or wastewater treatment, fits well with the 21st century focus on total water management.