Exploring Tradeoffs in Water Quality Management Using Environmental Data

This module was developed by Lofton, M.E., Cooke, R.L., and Carey, C.C. 20 September 2025. Macrosystems EDDIE: Exploring Tradeoffs in Water Quality Management Using Environmental Data. Macrosystems EDDIE Module 10, Version 1. https://serc.carleton.edu/eddie/teaching_materials/modules/module10.html. Module development was supported by NSF grants EF-2318861 and RISE-2438447.

Initial Publication Date: September 20, 2025

Summary

Many water management decisions come with tradeoffs. One important example of such a decision is the use of chlorine in the drinking water treatment process. Chlorination is an important disinfection step in water treatment and is needed to protect water consumers from harmful pathogens (such as bacteria). However, when there are high amounts of organic matter in the raw water, chlorination can result in the formation of potentially cancer-causing disinfection byproducts. Environmental sensor data on water quality conditions, such as organic matter measurements from drinking water reservoirs, can help inform water management decision-making and reduce the risk of unintended consequences due to use of chlorine in water treatment.

In this module, you will explore organic matter data collected from drinking water reservoirs and learn how to interpret these data to inform your decision-making about chlorination during drinking water treatment.

Focal Question: How can we use environmental data to inform our understanding of the tradeoffs involved in water management decision-making?


Learning Goals

By the end of this module, students will be able to:

  • Define what disinfection byproducts are
  • Describe the environmental and water treatment processes that influence the formation of disinfection byproducts
  • Understand the trade-offs between disinfection and byproduct formation that can occur when chlorinating water, and treatment techniques that can be used to manage these tradeoffs (e.g., coagulation, activated carbon filters)
  • Use environmental data visualizations to identify when additional treatment techniques to avoid disinfection byproduct formation should be used to meet water quality objectives

Context for Use

This module was developed as part of a virtual, asynchronous curriculum for students training to become water treatment plant operators. This entire module can be completed in one 2 to 3-hour lab period, two 75-minute lecture periods, or three 1-hour lecture periods. The module is designed to be fully accessible for both in-person, hybrid, and completely virtual, asynchronous courses. Open-source versions of all module materials are available on this website and module activities can also be imported into Canvas from the Canvas commons [ADD LINK]. Students complete module activities using an R Shiny web application, and can answer questions either using a Canvas quiz or by typing them into a student handout which can be downloaded from the app. Please see the instructor manual for detailed recommendations about module timing for different class schedule types.

Description and Teaching Materials

Quick overview of the activities in this module

See the instructor manual, provided below, for a step-by-step guide for carrying out this module. A student handout describing Activities A, B, and C, and an instructor PowerPoint are also provided.

  • Activity A: Students access and explore high-frequency water quality data from a drinking water reservoir in southwest Virginia.
  • Activity B: Students use high-frequency water quality data to explore how water quality changes and make decisions about water withdrawal depth over the course of a year.
  • Activity C: Students make management recommendations for water treatment using water quality forecasts.

What are disinfection byproducts?

Disinfection byproducts (DBPs) are compounds that are unintentionally created during the drinking water treatment process. Many of them are known to be carcinogens, or capable of causing cancer. There are dozens of DBPs; two common classes of DBPs are trihalomethanes (THMs) and and haloacetic acids (HAAs).

How do disinfection byproducts form?

Disinfection byproducts form when organic matter or inorganic compounds in drinking water sources react with chlorine during the disinfection process. Organic matter is derived from living organisms and contains carbon. The organic and inorganic compounds in raw (untreated) water that lead to DBP formation during treatment can either be naturally-occurring or introduced by humans.

How can environmental data help us avoid the formation of disinfection byproducts?

Some forms of organic matter can be measured using water quality sensors deployed in a drinking water reservoir. For example, fluorescent dissolved organic matter (fDOM) sensors measure organic matter and can indicate the presence of DBP precursors in the water. Many fDOM and other environmental sensors can provide data to managers in real-time or near real-time, which can help inform what additional measures may need to be taken during the treatment process as water quality conditions change to avoid DBP formation.

Workflow for this module

  1. Instructor chooses whether to deliver the module using Canvas or not. If using Canvas, the instructor should import the module to their course from the Canvas commons [ADD LINK]. If not using Canvas, all module materials can be accessed from this web page.
  2. Students view a short (~10 minute) introductory video either in Canvas or in the R Shiny web application. The same video is linked from both locations. Alternatively, instructors may choose to modify the introductory presentation and present it themselves. An editable version of the slides is provided with the teaching materials below.
  3. Students navigate to the R Shiny web application and follow the workflow instructions outlined on the Introduction tab:
    1. Watch the introductory presentation provided in Canvas and embedded in the interactive R Shiny web application if you have not already done so.
    2. Watch the "Guide to Module" video embedded in the interactive R Shiny web application to learn about key features of the module that will help you complete module activities and answer questions. Optionally, you can also go through the "Quick-start" guide to the module using the button at the top right corner of the module web page.
    3. Select a focal reservoir.
    4. Open the Canvas quiz questions associated with the reservoir you have chosen OR if you are not using Canvas, download a copy of all the questions as a Word document by clicking the "Download student handout" button.
    5. Work through the module to complete the Introduction questions and Activities A, B, and C in this web app. When you are prompted to answer questions, enter your answers in the Canvas quiz. Be sure to fill in the Canvas quiz that corresponds to the reservoir site you have chosen! If you are not completing the module using Canvas, you may type your answers into the Word document.
    6. If you would like to take a break and come back later, or if you lose internet connection, all you have to do is re-load this web app, re-select your reservoir site in the Introduction, and you will be able to resume your progress. On Canvas, you can save your quiz responses using the "Save" button. In Word, you can save your answers in the document on your computer.
    7. When you have finished the module activities, be sure to submit your Canvas quiz for grading. If you are completing the module by answering the questions in a Word document, be sure to submit the document to your instructor for grading.
  4. The instructor can choose how to assess student module question responses. If using the Canvas quiz, all self-grading questions are worth 1 point by default. The point values may be adjusted by the instructor. If using the Word document, point values are not assigned to questions; this is left to the discretion of the instructor.

Teaching Materials:

Teaching Notes and Tips

Important Note to Instructors:

The R Shiny app and other instructional materials used in this module are regularly updated, so these module instructions will periodically change to account for changes in the code. If you have any questions or have other feedback about this module, please contact the module developers (see "We'd love your feedback" below).

We highly recommend that instructors familiarize themselves with the Shiny app prior to the lesson. This will enable you to be more prepared to answer student questions.


Assessment

Student understanding is assessed using interactive questions embedded throughout the R Shiny application. To answer these questions, students will need to visualize and interpret high-frequency water quality data. Student responses are recorded either by entering answers into a Canvas quiz or by typing answers into a Word document report that they download from the application.

  • Activity A: Students explore how disinfection byproducts are formed during the drinking water treatment process and examine tradeoffs between disinfection and byproduct formation.
  • Activity B: Students view and interpret environmental data that can indicate when naturally-occurring DBP precursors are present.
  • Activity C: Students make water treatment decisions using environmental data that can indicate when DBP precursors may be present.

References and Resources

We'd love your feedback!

We frequently update this module to reflect improvements to the code, new teaching materials and relevant readings, and student activities. Your feedback is incredibly valuable to us and will guide future module development within the Macrosystems EDDIE project. Please let us know any suggestions for improvement or other comments about the module by sending an email toMacrosystemsEDDIE@gmail.comor filling out the form at the following link:https://serc.carleton.edu/eddie/macrosystems/faculty_feedback.

Module authorship contributions: MEL, RLC, and CCC conceptualized the module. MEL drafted and revised all module materials with substantial feedback from RLC and CCC.