Book 30, Question 101
What steps turn lake water into drinking water?
A treatment plant works in stages.
First, screens catch sticks and fish. Next, chemicals make tiny bits of dirt clump together. The clumps settle to the bottom of big tanks, and the clearer water flows through filters of sand and charcoal. Finally, chlorine or ultraviolet light kills germs. Workers test the water again and again before it goes out to homes.