Introduction

Engineering involves the application of fundamental scientific principles to the development and implementation of technologies needed to satisfy human needs. For environmental engineering the body of knowledge whose application defines the discipline is environmental science and the goal of the discipline is satisfying present and future human needs through protection of the environment. This chapter discusses the more narrow issue of the technical basis for assessing and eliminating the effects of pollutants in the environment. A model is nothing more than a representation of a system for the purposes of analyzing behavior and decision making. A system is simply the entire domain affected by the environmental problem in question while a model is a description of the processes of importance within the system. The basic types of models environmental systems are: conceptual models, physical models, mathematical models, algebraic models, ordinary differential equation models, and partial differential equation models.