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Clearwater to be pioneer in injecting treated wastewater into aquifer

CLEARWATER — Seven years ago, just the suggestion of transforming Clearwater's treated sewage into drinking water was an idea that got then-Mayor Frank Hibbard stopped in the grocery store.

"Is this being done anywhere else, are we the guinea pig?" he remembers residents asking. "There's a yuck factor there."

At the time, taking reclaimed water used to irrigate lawns and golf courses and purifying it to drinking standards was a relatively rare technology.

But recognizing the benefits, the city pursued it.

Now, after seven years of study, Clearwater has become the first city in Florida, and one of only a handful in the United States, to launch a design phase for a groundwater replenishment facility that will not only purify wastewater, but inject it back underground.

Engineering firm Tetra Tech has begun designing the $28.6 million plant, and city officials estimate it could be running by 2018 after design, permitting, and construction is completed.

And while the technology has been dubbed "toilet to tap" by skeptical communities that were pioneers, Clearwater officials are planning a public relations campaign to show that stigma is a complete misnomer.

The facility will take wastewater being treated for irrigation at the Northeast Water Reclamation Facility off McMullen-Booth Road and push it through a microfiltration process, reverse-osmosis system and ultraviolet light to remove all viruses, drugs and other pollutants.

The water will be clean enough to drink then and there, but it will flow through new injection wells back into the Floridan Aquifer, replenishing Pinellas County's stressed groundwater supply and eventually making its way to residents' faucets.

"It's kind of ludicrous to take the water, treat it to such a high level for irrigation, then just spill it on lawns when you could add another step and drink it," said Clearwater utilities director David Porter.

• • •

While Florida's water supply has not faced shortages seen in states like California and Texas, utilities are increasingly looking for ways to conserve as population and demand skyrocket.

In Tampa Bay, water supplies rely on summer rains to replenish surface waters and the groundwater that trickles into the Floridan Aquifer.

But when a drought rolls in, "this region drops into a water shortage in a really big hurry," said Alison Adams, chief technical officer for Tampa Bay Water.

Clearwater supplies about 9 million gallons of drinking water to residents a day and another 4 to 5 million gallons of reclaimed water for irrigation. The majority is pulled through city wells from the Floridan Aquifer, and the rest is bought from Pinellas County.

Like most utilities do to some extent, Clearwater discharges almost 3 million gallons of highly treated wastewater daily into Old Tampa Bay.

That's where the untapped opportunity lies.

"You're adding a nutrient-laden water to bays and estuaries and the Everglades and that kind of thing, which adds to algae growth problems," said Guy Carpenter, president of the WateReuse Association. "We don't want that water discharged to the environment, and we need water supplies for drinking supplies, so maybe we can clean that water to … respond to population demands and protect the environment."

• • •

Clearwater officials began investigating the safety and affordability of purifying reclaimed water by commissioning a feasibility study from 2009 to 2011. When that checked out, the city moved to pilot testing.

Officials built a small-scale groundwater replenishment plant in 2013 and tested the water for a year.

The Southwest Florida Water Management District pitched in $1.7 million for the pilot testing and will pay about half of the new facility's $28.6 million in construction costs.

In the process, reclaimed water is treated through microfiltration using fibers smaller than human hair to capture solids and viruses; reverse osmosis forces the water through membranes to further remove contaminants; and ultraviolet light and hydrogen peroxide disinfects and captures any remaining contaminants.

The end result of the pilot was water not only safe and free from pollutants — it was too clean.

Injecting such pristine water with no calcium or magnesium into the aquifer would dissolve the natural limestone, much like throwing water on a sand castle would break the bonds, said Porter, Clearwater's utilities director.

After minerals are added into the water, it will travel through five injection wells, pushing roughly 3 million gallons of water a day into the aquifer — water that came out of a resident's sink, traveled through their body, into the wastewater system and now back into the drinking water cycle.

This sort of reuse already occurs naturally when utilities pump treated wastewater into retention ponds and basins, eventually trickling into the ground and entering the drinking water system, but Clearwater would be the first in the state to directly inject it into the aquifer.

Steven Duranceau, associate professor of environmental engineering at the University of Central Florida, said the state's rising population and reliance on groundwater will push other cities to look at alternative sources.

While the nation's drinking water mostly comes from surface water, Florida relies more on pulling groundwater, a method that may not be sustainable.

"People think it rains so much in Florida, but no, it evaporates too," he said. "Anything that helps us keep our aquifers protected is a good thing."

And Clearwater's approach is more affordable than a large-scale desalination plant.

Clearwater modeled its facility on the largest and most well known groundwater replenishment plant in the world, which Orange County, Calif., launched in 2009 to inject 35 million gallons of treated wastewater into the ground each day.

"All we're doing is building a box to do Mother Nature's work," Porter said. "It's nothing different than what she's doing, we're just helping her do it faster."

Contact Tracey McManus at tmcmanus@tampabay.com or (727) 445-4151. Follow @TroMcManus.

Clearwater to be pioneer in injecting treated wastewater into aquifer 01/16/16 [Last modified: Saturday, January 16, 2016 8:22pm]
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