This book takes a fresh and unique approach to the study of environmental science and engineering, using concepts of materials balances, and reactions and reactors to integrate and unify its presentation of water supply, wastewater treatment, air pollution control, and solid and hazardous waste management. Vesilind also incorporates issues of ethics and ethical decision making throughout the text discussion and accompanying problems - challenging the reader to consider the ethical ramifications of problem solutions. The concept of materials balances unifies coverage of all types of environmental problems, including ecosystem dynamics, wastewater treatment, and air pollution control. The far-reaching nature of ethical issues, as revealed in the book's problems and case studies, illuminates the author's discussion of essential concepts.