2025 ASEE Annual Conference & Exposition

Chemistry is essential to many branches of engineering, including civil and environmental engineering. As examples, redox chemistry underpins corrosion of essential infrastructure and critical biotransformation of pollutants. Based on three years of pre-course surveys for CE 151: Water and Wastewater Engineering, civil engineering (CivE) and environmental engineering (EnvE) majors at the University of Vermont lack confidence in applying chemistry to solve engineering problems. CivE majors take one basic chemistry course prior to taking water and wastewater engineering, and EnvE majors have historically taken two introductory chemistry courses. According to students’ assessments of their learning gains, ~50% of students have reported good or great gains in their chemistry abilities because of taking water and wastewater engineering, but learning gains could be improved further. As part of curricular changes, EnvE students will only be taking one introductory chemistry course, similar to CivE majors. This means that the water and wastewater engineering course will provide both CivE and EnvE students with their first college-level redox chemistry. The hypothesis is the incorporation of two modules on redox chemistry – “the chemistry of the Flint Water Crisis” and “microbial degradation of pollutants” - will improve both affective and cognitive chemistry outcomes in a water and wastewater engineering course.

To test this hypothesis, the two modules were implemented in Spring 2024. These modules interweaved redox chemistry fundamentals (e.g., half reactions, electron donors and acceptors, electrode potential) with big-picture, real-world problems. A total of two 75-minute modules were implemented. To assess impacts on student learning gains, both cognitive and affective outcomes were assessed. Self-reported and observed gains were both analyzed. To accomplish this, a pre-course assessment was used to assess student understanding of redox chemistry and a pre-course survey asked students to report their confidence in applying chemistry to solve engineering problems. To assess observed cognitive outcomes, results of a post-module assessment were compared to a pre-module assessment covering multiple topics of redox chemistry. Further, a Student Assessment of Learning Gains (SALG) survey allowed students to report on their own learning gains related to chemistry. Additionally, SALG survey results were compared with past cohorts (n=3) to determine if the two new modules impacted learning gains.

Both the pre- and post-assessments consisted of four questions. Results of the pre-assessment showed that 40% of students could correctly identify an electron donor and electron acceptor in a complete redox reaction. No students correctly wrote half reactions for oxidation or reduction, with less than 40% of students attempting these two questions. No students were able to calculate the electrode potential of a combined reaction given the electrode potential of half reactions. In total, the pre-assessment confirmed that even students who had completed two introductory chemistry courses retained only minimal information on redox chemistry. After the modules, students were much more likely to attempt the questions, but performance was still poor. The number of students who could correctly identify an electron donor and acceptor decreased from 40% to 35%. While greater than 75% of students attempted to write the oxidation and reduction half reactions, no students got the problems completely correct. The greatest improvement was in the final question related to electrode potential. While no students provided a correct answer on the pre-module assessment, 47% of students did this problem correctly on the post-assessment. In the final SALG survey, 45% of students reported good or great gains in their confidence in applying chemistry to engineering problems. This is much higher than reported in the pre-course survey (27%) but is lower than past cohorts in which 65-78% of students reported good or great gains in their chemistry confidence. Interestingly, 98% of students responded that they agreed or strongly agreed that chemistry is important for EnvE.

In summary, these results show that the two modules improved cognitive outcomes related to calculating and interpreting electrode potential, but students did not perform substantially better at identifying electron donors and electron acceptors or writing half reactions from scratch. While gains in confidence in using chemistry were reported, the number reporting good or great gains was lower than previous cohorts. It must also be noted that during the Flint Water Crisis module it was discovered that most students had not heard of the Flint Water Crisis. This was a surprise, since all past cohorts had covered the crisis in an introductory environmental systems course. Therefore, the instruction pivoted in real-time to highlight the social and historical narratives of the crisis which reduced the amount of time spent on the chemistry. This resulted in 82% of students reporting good or great gains in their overall understanding of the Flint Water Crisis, a large increase compared to past cohorts that were previously taught about the crisis before the course. Therefore, moving forward, at least two lectures should be spent on the Flint Water Crisis. Further, a new required course for EnvE students, Environmental Engineering Chemistry and Microbiology, will provide in-depth instruction on redox chemistry related to both water and air chemistry. This will expose EnvE students to in-depth instruction on redox chemistry, but the question remains: how much redox chemistry do CivE students need to know and is it worth the time to ensure fundamental concepts are grasped in a water and wastewater engineering course? Corrosion prevention is essential in a world of aging infrastructure, but rather than fitting it all into a water and wastewater engineering course, we propose implementing these concepts in structural and geotechnical engineering courses so that students interested in these disciplines see the direct application.