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This program traces the
water cycle, beginning with the collection of rainwater in rivers and lakes,
in great detail through a water treatment plant, to some of the places where
water is used, and finally back into the atmosphere. Treatment of the water
begins with the use of chlorine to destroy organisms; the water is then
filtered through various sedimentation tanks to remove solid matter. Other
treatments employ ozone, which oxidizes everything and makes it easier to
remove; hydrated lime, which reduces the acidity of the water; sulfur
dioxide, which removes any excess chlorine; and flocculation, a process in
which aluminum sulfate causes small particles to clump together and
precipitate out. Throughout various stages of purification, the water is
continuously tested by smell, taste, titration, and by fish. The treatment
plant also monitors less common contaminants with the use of up-to-date
techniques like flame spectrometers and gas liquification. (20 minutes)
©1987
ORDER CODE: FFMBVL1278V
VHS
VIDEO
ORDER CODE: FFMBVL1278DVD
DVD
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