Where Does Tap Water Come From?
Before arriving at your tap, drinking water has to be treated and cleaned all of impurities.Whether for basic groundwater contamination or the introduction of industrial wastewater (70% of which is dumped into nearby bodies of water, polluting them), “dirty water” is abundant across the Earth. Consider that of the total amount of water on Earth , only 3% of it is fresh water; moreover, only 1% of all water is deemed suitable for drinking.
With the percentage of drinkable water being so minuscule, it is of interest as to just how we turn dirty water into clean water. The means through which this is accomplished is through the water treatment process.
The water treatment process takes place by first having a water source from which water is collected. Over 95% of all fresh water resources come from ground water. Similarly, nearly half of Americans’ drinking water comes from these ground water sources. From there, the water treatment process goes through a number of steps, all towards the means of ending up with fresh drinking water:
Pre-Chlorination and Aeration: The dirty water is chlorinated and rapidly mixed, adjusting the pH and removing any trace amounts of iron and manganese that are still present.
Coagulation/Flocculation: A chemical compound is added to the water mixture, causing other chemicals to bind together to create a large particle called “floc.” The water is separated into separate basins where it’s flow will be slowed. During this time, the floc has time to grow increasingly larger.
Sedimentation: The water is transferred into separate basins once again. Here the water will go through a separation process, such that the solids trapped within the floc will sink to the bottom of the tanks. Only then can they finally be removed from the mixture.
Filtration: The water is now made to pass through washable filters made of gravel, sand, and other grainy compounds. These filters are able to remove any larger particles that might still be present from the sedimentation phase, whether that be microorganisms or particles.
Disinfection: In this phase, the water will be treated with various chemicals (normally a mixture of chlorine and ammonia) that will disinfect the water of any bacteria or pathogens still present in the water.
Finally, once the entire water treatment process has finished, the distribution process takes place: this water is either pumped to the homes within the facility of the water treatment plant, or it is bottled and shipped for consumption en masse. By taking water reserves and putting them through the water treatment process, water is easily turned from dirty to clean.