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Flagstaff Water Services is considering Advanced Treatment to convert reclaimed water into clean, safe drinking water.
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Reclaimed water is water which has been collected at one of the water reclamation plants and treated so that it is clean enough to be reused for purposes other than human consumption.
The reclaim water treatment process begins with wastewater collection. The collected wastewater first passes through screens to remove large objects from the water. Next, inorganic particles are removed. It then goes on to biological treatment. In this phase, good bacteria digest organic compounds in the water. After the biological treatment phase is completed, the water is further filtered to remove any remaining particulate matter. Finally, the water is disinfected through UV treatment and chlorination.
While reclaimed water treatment does clean waste water, it does not produce water that meets drinking water standards. Typical uses of reclaimed water include irrigation, flushing toilets, surface water discharge (Rio de Flag), and groundwater recharge. Reclaimed water can undergo further treatment to meet drinking water standards. This level of treatment is referred to as Advanced Treatment.
The City of Flagstaff uses reclaimed water for irrigation, industrial, and other purposes, to conserve potable water sources for human consumption and household uses. As the only current water resource that grows with population, reclaimed water is a vital component to the sustainability of our water supply.
Advanced Treatment is the industry term for a water treatment process, or series of processes, that are capable of removing trace contaminants in water that may not be removed through conventional treatment methods. These contaminants could include pharmaceutical products, artificial sweeteners, and even caffeine. Examples of processes that are considered Advanced Treatment include Reverse Osmosis, Membrane Filtration,and Water Oxidation.
Compounds of emerging concern - or CECs - have gained notoriety in recent years. CECs include pharmaceuticals, personal care products, endocrine disruptors, and antibiotic resistance genes that can turn up in water supplies. They are unregulated by federal and state water quality agencies because they occur at extremely low concentrations - nanograms per liter. In fact, laboratory equipment could not detect the compounds at these concentrations until about 2002. Improvements in analytical technology now allow labs to detect compounds well below the concentrations known to impact public health. CEC concentrations are very low in Flagstaff’s water, as they are in most communities. To put this into perspective, the Water Research Foundation estimates that you would have to drink 1.7 million 8-ounce glasses of water to get the equivalent of a single medical dose (e.g., one pill) of a pharmaceutical compound. Read more about this calculation.
Find more information on CECs
Yes, Ozone Treatment, Reverse Osmosis as well as Membrane Filtration, all serve to remove over 99.999% of pharmaceuticals and other Compounds of Emerging Concern (CEC) from the water. The City is considering which options are best for Flagstaff. See two examples of how a treatment train (the industry term for a series of treatment processes) works:
No, Advanced Treatment produces water which has been purified and is completely safe to drink. While reclaimed water is clean, it does not meet drinking water standards.
No, none of the City’s drinking water comes directly from the Rio de Flag. The Rio de Flag is an ephemeral river that flows seasonally, during times of rain or snowmelt. Flagstaff Water Services keeps this seasonal river flowing year-round with the discharge of reclaimed water from both the Rio de Flag and Wildcat Hill Water Reclamation Plants. Some of this water infiltrates underground into the underlying aquifer, where it co-mingles with groundwater.
Yes, the City of Flagstaff has an agreement with the Arizona Department of Game and Fish to ensure an adequate supply of reclaimed water is always being discharged down the Rio de Flag. This agreement would still be in effect even if the City decides to begin turning reclaimed water into Advanced Treated Water.
All water produced in the City of Flagstaff is currently held in storage tanks before distribution to the City. The water is tested as it enters the storage tank, and not released until the test results are completed and reviewed. Flagstaff Water Services ensures all water meets the standards for safety and quality before distribution.
No. The recharge wells do not use the same process as fracking. Injection wells are shallow, and have a minimal environmental impact under the ground. Recharge wells use much lower pressures than fracking operations.