Preparing Mississippi River Water for Drinking
The Route Water Takes “From River to Faucet”
An article in an Iowa newspaper (“From River to Faucet,” from The Hawk Eye) describes the step-by-step process used to process Mississippi River water for drinking in several Iowa cities, including rural Des Moines. Here are the steps.
Water drawn from the river is treated with potassium permanganate, which removes a lot of the taste and odors of river water.
Then, the water is treated with two coagulants: cationic polymer and aluminum sulfate. These separate the water from dirt particles, getting the water closer to the clear liquid that comes out of faucets.
From there, the water is treated with lime, which softens it. [The process referred to is called “lime softening.” It is not the equivalent of softening with an ion exchange water softener. The article comments that after the softening process, the water is “still fairly hard.”]
From there, the water plant adds fluoride “to prevent tooth decay” and sodium, which helps prevent water from depositing in water mains.
“Sodium also provides a coating to water mains and pipes, helping prevent problems like those in Flint, Mich., where thousands of children were exposed to unsafe amounts of lead. Especially in areas with older houses, such as Flint or Burlington, pipes can be made out of lead and copper, both of which cause health issues if people are exposed to too much of them. Water that travels through those pipes without first being treated can corrode the pipes, sending dangerous chemicals into the water people drink or cook with.”
Water finally is treated with ammonia as a long-lasting disinfectant before being pumped up for distribution to consumers or storage in a water tower.