Using backpacking water purification systems as a means of introducing water treatment concepts to an introduction to environmental engineering course
Active and experiential learning activities are highly regarded for delivering engineering content. This paper explores an inexpensive hands-on activity where students purified lake water using backpacking systems as a way to introduce water treatment concepts in an Introduction to Environmental Engineering course. Teams of two students were given one of the following methods of water purification: membrane filtration, membrane filtration coupled with an activated carbon adsorption, ultra violet disinfection, iodine tablet disinfection, solar water disinfection (SODIS), or disinfection via boiling. As part of this assignment, students evaluated the treatment methodologies in terms of their cost, ease-of-use, energy requirements, time of treatment and efficacy. They made observations about the effectiveness of their particular method by inspecting the reduction color, turbidity, and odor. In addition, they kept track of the time it took to purify one liter of water. Students also calculated the amount of time it would take to purify the minimum amount of water necessary for sustaining a person in one day as recommended by the World Health Organization and assessed the appropriateness of using each of the technologies in the developing world. Following this class session, students researched their respective purification technique and reported back to the class on its mechanism for removing contaminants as well as its limitations. The students then collectively discussed the tradeoffs of each method and debated which one would be most effective under a range of conditions such as turbidity, volume needed, availability, and cost of materials. This activity was followed by in class lectures on water quality and conventional drinking water treatment methods, which were related back to the backpacking water purification techniques. Overall, these activities were successful in providing a meaningful and engaging way to introduce physical and chemical treatment processes while concurrently examining water quality issues in the developing world. Student feedback from these activities was positive, and students demonstrated proficiency of water treatment concepts on subsequent exams. Numerous students reported that the activity helped them understand the principles behind water treatment while also challenging their preconceived notions about water treatment technologies in the developing world.