The answer to this question must be tied to the definition of engineering itself. Engineering may be defined as the application, under constraints of scientific principles, to the planning, design, construction, and operation of structures, equipment and systems for the benefit of society. Environmental engineers deal with structures, equipment and systems that are designed to protect and enhance the quality of the environment and to protect and enhance public health and welfare.

For example, the environmental engineer plans, designs, constructs, and operates sewage treatment plants to prevent the pollution of receiving streams. In other words, these structures are built to protect and enhance water quality. The environmental engineer also builds and operates water treatment plants. Clean, bacteriologically safe drinking water protects and enhances public health. Environmental engineers plan, design, construct and operate air pollution control equipment. The resulting cleaner air is conducive to people’s good health and prevents the deterioration of materials through the harmful effects of air pollution. Such equipment thus protects and enhances public health and welfare.

Environmental Engineers focus on the design of collection and treatment processes for air, water, wastewater, and solid and hazardous waste, including study of the conceptual principles underlying biological, physical, and chemical treatment. Therefore, Environmental Engineers must have a thorough understanding of:

• physical, chemical and biological processes fundamental to understand the environment fate and engineered treatment of environmental contaminants.
• the source and nature of waste materials that contribute to water, air and soil pollution and relevant management and control technologies.
• the transport and transformation of contaminants through environmental pathways.
• the technologies and designs associated with the treatment and disposal of waste materials.
• the connection between the engineering and scientific aspects of environmental problems and decision-making processes.

Improved understanding in all of these areas is achieved through a quantitative program built around the common theme of engineering and science in support of environmental decision-making.