The article discusses the importance of environmental engineers understanding fundamental principles to solve pollution problems. It covers a wide range of topics in environmental engineering, such as air and noise pollution control, solid waste processing, and water resources. The authors aim to provide a comprehensive overview of physicochemical treatment processes and other environmental fields. They use a multithematic approach to show how air, water, land, and energy are interconnected in pollution control. The authors hope that their use of both British and metric units will be helpful to readers.