Using Matlab-generated numerical solutions in an environmental engineering class to predict the fate and transport of contaminants

Abstract

Contaminant transport and fate is an important topic in environmental engineering. Closed-form solutions exist for homogeneous domains; however actual contaminated sites are rarely homogeneous, which means that no-closed form solution exists. An alternative to closedform solutions is a numerical solution through computer programs. Although commerciallyavailable software packages have been written to model contaminant transport and fate, a student-written program is chosen in this work for pedagogical reasons. With contaminant transport being an application of the differential equations, students in the senior-level environmental engineering class, Hazardous Waste, were introduced to analytical and numerical solutions of the partial differential equations governing contaminant transport, and then they used Matlab to investigate and predict the contaminant behavior in time and space, by modeling the data available from the Environment Protection Agency (EPA) website of a contaminated site. Students worked in groups, for four weeks, to model the contaminant concentrations over time and distance. A survey at the end of the project and comments from the course evaluations indicate that the Matlab modeling exercise, although challenging, was well received. Students were able to predict the time when the concentration of the contaminant drops below the maximum allowable concentration in drinking water. They also were able to model the movement of the plume. When asked about the importance of learning a computer language, 92% stated that this skill and knowledge are very important and will help them in their job applications, 76% stated that modeling the plume helped them visualize its spread and predict its fate. For future offerings, more time will be provided for the project and time will be allocated in class to work on the project. In addition, sites with time-varying boundary conditions will be introduced, as well as student assessment prior and after completing the computer assignment.