Several years ago we were looking for a laboratory activity for our industrial pollution control class at Bowling Green State University that would cause our students to think more actively about water pollution. We wanted to give them the opportunity to develop methods to take pollutants out of contaminated water. Creating water-scrubbing devices seemed like an ideal project for the students to study the mechanics of industrial water pollution control. At the same time we were interested in the development of other skills. Those skills included brainstorming, problem solving, creativity, team building, and oral and written communication skills. Teachers in high schools and middle schools could accomplish all of the skills that were developed in the college course.
Elimination of polluted water has been for some time a major concern of many Americans. Congress originally passed the Safe Drinking Water Act in 1974 to regulate the country's drinking water supply (EPA, 1999). The Clean Water Act, which came from an amended law in 1977, regulates discharges of pollutants into our nation's streams, rivers, and lakes (EPA, 2001). Benjamin H. Grumbles, Deputy Assistant Administrator for Water in the U.S. Environmental Protection Agency, said in a February 26, 2002 speech before a Senate Committee, "... we need to make sure that all Americans will continue to enjoy safe drinking water and clean rivers, lakes, and coastal waters." Terrorist threats, since the attacks on 9/11, have increased those concerns about the safety of our water supplies. Even with this new threat, our biggest problem comes from our own pollutants produced by our businesses and industries.
The students were encouraged to research water pollution scrubbers on the Internet. We suggested, as a starting point, they use the Environmental Protection Agency's (EPA) site.
As with any laboratory exercise our first concern was to create a safe environment for our students. Not only must we be concerned with the safe operation of equipment but also with the safety of the materials used to create the polluted water samples and the materials used to clean those samples. Engstrom (2001) reported that technology educators, in a recent study, chose "Safely use tools and machines" as their number one component of a good technology activity.
Creating Polluted Water
Our initial question was, "What contaminants do we want in our polluted water?" The second, and more important question was, "How do we make polluted water that is safe for our students?" The idea of using household items that are considered safe, but accurately represent the chosen pollutants, was our final choice. Acids, oils, metals, biological contaminates, and chemical discolorations were chosen to be the pollutants we wanted in our water samples. Then, with a little brainstorming, we arrived at the decision to use the following common household items to represent those pollutants.
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The students had to create a system that would allow them to pour the polluted water in one end of their system and have the water emerge clean from the other end of the system. They were limited to 30 minutes of time for the scrubber. This time constraint limited the students to using mechanical and chemical methods for purifying the water. Biotechnology methods would not perform effectively in this short time frame. If more time is available, biotechnology methods could be pursued. The polluted water that the students had to clean was made with a mixture of one cup of vinegar, one cup of corn oil, one tablespoon of red food coloring, and one cup of clay soil that contained organic materials, blended with one gallon of well water with a high iron content. The students were given some simple rules to follow:
1. All materials used for the scrubber system have to be items commonly found around the home, and they must be considered safe for the home. …