Simple Way to Remove Mud from "The water has a lower sodium concentrationDrinking Water than Gatorade," Pearce says. This would still be too much salt to pass muster as American tapNAME _____________ Date_____ Per__ water, but American tap water is not the alternative.Leaving bottles of water in the sun kills "Ive drunk this water myself. If I werepathogens--but only if the water is transparent. somewhere with no clean water and had kidsMichigan Techs Joshua Pearce has devised a with diarrhea, and this could save their lives, Idsimple way to clarify water, so even muddy use this, no question," he says.water could be made safe for drinking. (Credit:SODIS Eawag photo) Salt works best when the suspended particles are a type of clay called bentonite. The techniqueScienceDaily (May 1, 2012) — Nearly 80 doesnt work as well with other kinds of clay.percent of disease in developing countries is However, by adding a little bentonite with thelinked to bad water and sanitation. Now a salt to water containing these different clays,scientist at Michigan Technological University most of the particles glom together and settlehas developed a simple, cheap way to make out, creating water clear enough for SODISwater safe to drink, even if its muddy. treatment.Its easy enough to purify clear water. The solar Pearce and Dawney are running more tests onwater disinfection method, or SODIS, calls for water containing various types of clays, and theyleaving a transparent plastic bottle of clear water are also investigating different soil types acrossout in the sun for six hours. That allows heat and Africa to see where their methods might workultraviolet radiation to wipe out most pathogens the best.that cause diarrhea, a malady that kills 4,000children a day in Africa. Review Questions CornellIts a different story if the water is murky, as it 1. On what date was the article written?often is where people must fetch water from 2. Nearly 80% of disease in developingrivers, streams and boreholes. "In the developing countries is linked to what factor?world, many people dont have access to clear 3. What does the water purification methodwater, and its very hard to get rid of the of SODIS calls for?suspended clay particles," says Joshua Pearce,an associate professor of materials science and 4. What does the heat and ultravioletengineering. "But if you dont, SODIS doesnt radiation do to the water?work. The microorganisms hide under the clayand avoid the UV." 5. What do microorganisms do in muddy (clay) water?Thus, to purify your water, you first have to getthe clay to settle out, a process called 6. What is the name of the process thatflocculation. Working with student Brittney causes clay to settle out of the water?Dawney of Queens University in Ontario,Pearce discovered that one of the most abundant 7. What mineral is used in this process?minerals on Earth does this job very well: 8. What happens when salt combines withsodium chloride, or simple table salt. benotite?Salt is inexpensive and available almost 9. What happens to the water for theeverywhere. And it doesnt take very much to SODIS treatment?make muddy water clear again.
10. What did Pearce and Dawney want to investigate?