How Surface Water is Treated for Drinking

Written by Business Success on . Posted in Dirty water, Pfoa, Water treatment

The United States has some of the best water on earth, and a lot of money, time, effort, and technology goes into making our surface water safe. Before it reaches the taps in your home, water undergoes quite a number of processes, each of which is crucial to keeping our drinking water safe.

Entering the Water Treatment Plant

Water’s first stop is the water treatment plant, and there it will go through coagulation, flocculation, sedimentation, disinfection, and sometimes a few other steps as well.

  1. Starting the process with coagulation. The coagulation step mixes certain coagulants, like aluminum sulfate, with the water to change the charge of the particles of undesirable elements in the water. This change in charge causes them to clump together into larger groups called flocs.
  2. Flocculation makes things bigger yet. The next step of treatment agitates the flocs so they run into one another and stick, making even bigger particles than before. Now it’s ready for the sedimentation step.
  3. Sedimentation settles out the big groupings of flocs. The water goes slowly through a tank, and this gives the flocs time to fall to the bottom. As this happens, the water is passed through a filter, which gets rid of many other contaminants of concern. Some treatment plants will also use activated carbon, which removes man-made chemicals and other unwanted pathogens.
  4. Disinfection destroys all remaining pathogens and organisms. Chlorine, chloramines, ozone, or some other disinfectant is added to the water in this stage in order to destroy all bacteria, viruses and organisms that could be harmful to humans.
  5. Further protective steps guarantee safety to the tap When disinfectants are added, enough are added in to continue killing pathogens while the water is in the delivery pipelines. Because of concerns about chlorine, many treatment centers are testing other methods of disinfecting water, however, all alternatives have their own potential health risks, and the health risks of skipping the disinfection stage are not worth risking. After the disinfection stage, some treatment centers aerate the water by adding air to it in order to reduce the amounts of iron and manganese in the water. Some treatment centers will then add fluoride to reduce the incidence of tooth decay in the population.

Water Subject to Treatment

All surface water that is sent into the pipes for drinking has to be treated, whether it comes from lakes, rivers, streams, or other water systems. Unless the water supplier is able to show definitively that the water has never been exposed to contaminants, most states will mandate full surface water treatment for all surface water sources. Surface water usually needs more treatment than groundwater because surface water is exposed to far more contamination. Most communities also mandate regular reports on the quality of the local drinking water.

Surface water treatment helps to guarantee the safety of the water supply and allows Americans to drink freely from the tap without fear of the diseases that used to make drinking ordinary water dangerous. And now, when 70% of the world’s industrial waste is dumped into the nearby bodies of water, polluting the water supply, it is even more important that all our water be properly treated before it reaches our taps.

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