Objectives:
Using this Project WET activity, students will:
- illustrate how demands on some treatment plants cause overflow.
- explain problems with sewage overflow.
- propose solutions to a water management problem.
- recognize how presentation strategies influence public policy.
Materials:
- Tokens or popcorn
- Cups
- A bucket or other container
- Copies of Included Reading
- Chalk
Procedure:
Part I:
- Ask the students if they watch the Super Bowl or favorite special program a large group would watch. Ask them what they do during halftime or a commercial! Tell them they will be participating in a demonstration showing what happens to wastewater treatment systems when unusually large numbers of people flush at once.
- Draw a T on the floor with chalk. Have pairs of chairs facing each other along the long part of the T. (The sewage pipe is buried along this chalk line.) Have the students sit in chairs (each chair represents a hous). Have two students stand at the cross of the T. (These students are the treatment plant with the river behind it).
- Each chair gets a cup of popcorn representing waste materials.
- Tell the students that 5 seconds are required for the plant to clean the waste from each house. One student from the end of the T collects the popcorn while the other counts to 5. Only one piece of popcorn may be collected every five seconds.
- Have the other students sitting in the chairs and have each count off from one to four. When you call "Flush!" and a number (1,2.3 or 4), students of that number should pick up one piece of popcorn, walk to the treatment area, standing at arm's length from the person in front of them.
- When a student gets to the treatment plant, they give the popcorn to the plant and return to their home (chair). This is repeated for all of the people with the number called. If all of the students have their waste treated in one minute, the system does not overflow. Call out "Flush, one" for an example. Do this several times.
- Now call, "Flush, one, two, three, four." All students will move to the pipe, standing arm's distance away from the previous person. It takes 5 seconds for each person to deposit the popcorn, so all will not be complete in one minute. (If you have fewer than 12 people in your class, modify the time limit to 15 or 30 seconds.) The system has backed. Tell the students still waiting to drop their popcorn behind the two treatment plant people and return to their seats. This represents untreated sewage that goes directly into the river. Look at how much is there compared to how much was treated.
- Have all students return to their seats and discuss their reactions. Are there times when many people flush their toilets at once? Ask them what problems might arise from untreated sewage being dumped directly into a water source. Responses migh be: odorous water, tainted water leading to health hazards for game, domestic animals, and people (bacteria, viruses and protozoa in sewage can end up in the water and get into the intestinal system of humans and other animals; waterborne diseases like dysentery and hepatitis are transmitted by contaminated water); single-celled organisms take up too much oxygen if they are concentrated so regular plant and animal life cannot survive.
Part II:
- Divide the class into four groups and give each a copy of Treatment Plant Braces for "Super Sunday" Surge. Tell each group that they are consulting teams and that each will prepare a report that includes a proposed solution.
- Teams must consider the following: - A description of the problem and why it concerns the community (health hazards, environmental impacts, etc) - Individuals or groups in their community who would be affected by untreated water overflowing into the river (birdwatchers, health department, farmers, US Environmental Protection Agency, wildlife, treatment plant, etc) - Details of the effect of sewage overflow on one or more community groups. (Have each team think about a different group) - A recommended action plan for solving the potential overflow problem. The plan must address related environmental, economic, and social issues, including a report on the potential impact of sewage overflow on the community groups.
- Discuss: Who will be affected? How will the plan ensure that community members will cooperate? What will be the cost? Who will pay? How will they pay? How much is each resident willing to pay?
- Have guest teachers, principal, and/or parents visit the classroom to be on the evaluating board. Or have each team select a member to create the board that evaluates all of the plans.
- Each team will present their report and solution in a 5 minute proposal to the class. Provide each team with a copy of the Supplemental Form.
- Teams can be given any length of time to prepare (minutes, days, week, etc)
- Have teams discuss the decision making process. For more information, request a sewage flow graph from a local treatment plant. Notice peaks on the graph. When did they occur?
This activity is available as an Adobe PDF.
Wrap Up