Scenario-Based Teaching of Activated Sludge Processes Using an Excel-Based Simulation Tool

Abstract

Scenario-based teaching supported by computerized solutions is an effective way to increase student engagement and to improve conceptual understanding in engineering education. In this study, we present bioXL3p, an Excel-based simulation tool designed to help undergraduate environmental engineering students learn fundamentals of activated sludge processes. A structured set of in-class and homework simulation activities, which aims to reinforce theoretical knowledge through guided simulations, was developed in which students are instructed to conduct computer simulations using bioXL3p. A total of 15 activities comprising 7 for carbon removal and fundamentals, 6 for nitrogen removal and 2 for phosphorus removal were proposed. The activities are well aligned with program outcomes from national and international accreditation frameworks such as ABET, EUR-ACE, and M & Uuml;DEK, focusing on problem analysis, simulation-based design, and lifelong learning skills. The method was implemented with a total of 23 students over 4 years. After excluding inconsistent responses, participants reported high perceived gains in conceptual understanding (mean = 4.53; N = 17) and confidence in applying activated sludge modeling to design problems. The accompanying database and supporting materials provide an open-source resource for integrating proposed method into environmental engineering curricula. Future development plans include more flexible versions of the tool (possible bioXL Pro and bioXL Ultimate), enabling model selection and user-defined model structures.