Rio de Flag Water Reclamation Plant Tour

Guest Blog Post by Rose Houk

It’s pretty easy to just flush the toilet and forget where our human waste goes. For most of us, it’s “out of sight, out of mind.”   

But on a Saturday in April, nearly 50 interested residents toured Flagstaff’s Rio de Flag Water Reclamation plant to look a little deeper into where our wastewater goes once it leaves our homes and businesses.

It turns out the behind-the-scenes story is really interesting.

This is not a landed UFO, but the primary tank for the treatment process at this facility built in 1993.

The Rio de Flag Water Reclamation Plant is a clean, attractive building standing just beyond Sam’s Club by a trail along the Rio. Inside are bright offices, maps on the walls, and a friendly city employee, Jim Huchel, who greeted us and led the tour.

Once we were all signed in, Jim gave us a firsthand look at the reclamation process from beginning to end. The plant, built in 1993, receives wastewater from the west side of Flagstaff. It first comes into the “primary clarifier,” what looks like a big black spaceship that just touched down. We peered inside to see a thick, dark, watery substance just sitting there. 

Peering into the Primary Clarifier Tank where the water spends 2 - 4 hours getting grease and flotables skimmed off.

Unseen were the natural bacteria that were beginning to biologically alter the wastes. Some of the material in the chamber stays suspended, while other parts sink. The suspended solids are skimmed off and sent down to the city’s other water reclamation plant at Wildcat Hill.

In the next step, the liquid enters a secondary chamber where it’s further clarified. It then flows indoors where it’s treated with ultraviolet light for a third step of purification.

Jim poured the water into a wineglass, and it looked good enough to drink. In fact, it’s graded as Class A+, but under Arizona regulations reclaimed water can’t yet be used as potable, or drinking, water.

Residents had lots of questions:  Is the reclaimed water okay to put on plants? Is it safe to drink? Using reclaimed water for drinking will take getting over the “yuck” factor, said Erin Young, the city’s water conservation manager. She noted that Arizona is devising regulations that might make that a possibility.

Solar panels between the Secondary Tank (back) and Primary Tank (front) power the water reclamation system.

The Rio de Flag plant can treat up to four million gallons of wastewater each day. In summer, nearly all the reclaimed water is spoken for –to irrigate fields, parks, and golf courses, some residences, and for industrial uses. In winter, the city sells excess reclaimed water to the Arizona Snowbowl for snowmaking. A certain percentage also goes back into the Rio. According to the city, reclaimed water accounts for about 20 percent of Flagstaff’s total water use.

Next time you see those purple pipes and signs indicating reclaimed water, it will have a whole new meaning. 
          

A Big STEM City Thank You to Rose Houk for this post! And to Jim Huchel and Erin Young of the City of Flagstaff for this engaging and educational tour!