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Behind the Scenes at a Gilbert, Arizona Water Treatment Plant

Post Date:11/14/2017 5:28 PM

Gilbert, Ariz.- You and your family count on the reliable water service provided by Gilbert—but what does it take to treat water that’s safe to drink? Before water is put into the water distribution system, it is treated at one of Gilbert’s two drinking water treatment plants. In this month’s water blog, come behind the scenes of the North Water Treatment Plant, where lightning ozone chambers and midnight water quality lab tests are just some of the safeguards for the water coming out of your tap. 

Gilbert’s water comes from groundwater, the Salt, Verde, and Colorado Rivers. To treat this water so that it's safe to drink, it takes:

Water Blog - Behind the Scenes at a Gilbert Water Treatment Plant2 Screening Gates
• Before water is taken through the treatment process, screening gates ensure leaves and other debris is removed.

2 Pre-sedimentation Basins
• Gravity settles out any sand, grit, and gravel in the water.

2 Ozone Contactor Chambers
• Water comes in contact with ozone, which is generated by sending electricity through a chamber. 
• Electricity + oxygen = Ozone. This lightening-like effect is used to kill disease-causing bacteria and viruses.

6 Final Sedimentation Basins 

• Flocking agents like alum are added and rapidly mixed into the water to encourage any remaining particles to come together and sink to the bottom of the basin, leaving the clean water on top to continue moving through the treatment process. 

18 Drying Beds
• The material from the bottom of the sedimentation basins is transported to drying beds where the remaining water evaporates. 
• The remaining material is inert and is hauled off to be used as topsoil in local landfills.

18 Filters 
• Think big sand filters—2.5 million gallons per day (MGD) big. 
• After water is sent through the filters it is considered “finished” water, disinfected with chlorine, and placed into the onsite 16 million gallon reservoir for distribution into the system to meet Gilbert customers’ needs on-demand.  

2 Onsite Water Quality Testing and Compliance Laboratories 
• Throughout the treatment process, results are automatically generated from the various water quality monitoring instruments. 
• Gilbert chemists double check these instruments’ readings every 4 hours to assess water quality at the plant, including during the middle of the night. 
• Gilbert tests and monitors your water for inorganic chemicals, organic chemicals, disinfectants and disinfection byproducts, and microbiological contaminants.

ater being delivered to presedimentation basins Water Quality Sampling Annual powerwashing of sedimentation basinsBackflushing sand filters alve opening to allow water to pass through the filter below

Producing potable water at the drinking water treatment plan is just one aspect of what it takes to ensure it is safe upon delivery to your Gilbert home, school, church, or business. This potable drinking water is not only used indoors for cooking, bathing, and flushing, but also outdoors on landscapes. Roughly 65% of the water Gilbert treats to drinking water standards is used outdoors. Water is precious here in the desert. You can do your part to save, visit:

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