The city of Cottonwood could be drinking its reclaimed wastewater in 15 or 20 years, said Dan Lueder, the city's head of development.

Actually, he nearly crowed this point.

"It looks like this is going to be the future of water re-use in Arizona," Lueder said.

Cottonwood got into the drinking-water-production business in 2005, and it just happened to be sitting on a tax for big public projects that had accrued over about 20 years.

So Cottonwood plans to build an $8 million, solar-powered plant capable of breaking apart many trace synthetic compounds by blasting them with ozone and hydrogen peroxide.

The facility will likely have higher energy needs, but they'll be met mostly or entirely by the sun.

The city's council figured it should build a facility to remove trace contaminants both for the health of the Verde River into which it discharges and because regulators would probably require it someday.

"We're looking at pharmaceuticals being the next big thing," Lueder said. "... If we don't remove them from our reclaimed water, we'll never get them out of our water supply."

The raw sewage flows into a large screen to remove major solids, then into a tank where bacteria eat more solids, then into what's called a "clarifier" where more solids separate from the water, and then into an oxygen-free zone that further removes solids.

The wastewater next gets filtered through sand.

All of that is not vastly different from what happens at the Rio de Flag plant.

But in Cottonwood, the water will next be sent into a winding system where it gets blasted with hydrogen peroxide and ozone, something called "advanced oxidation" treatment.

Ken Knickerbocker is engineering that part, and it will be capable of reducing chains of organic compounds.

"It will attack them and essentially break them down," he said, without the chemical byproducts that now result from some disinfectants, like chlorine.

Put another way, researchers describe these as potent, short-lived, extremely reactive radicals that are able to oxidize and break organic molecules into carbon dioxide and inorganic ions.

After that, Cottonwood's wastewater will be sent into another filter (perhaps a very fine membrane), and then for ultraviolet treatment.

Trace synthetic organic contaminants are already reduced to amounts measured in parts per billion and parts per trillion before these final treatment mechanisms, and this will reduce them more, Knickerbocker said.

Lueder told the Cottonwood City Council he wanted to build a plant that was partly solar-powered and which could serve as an educational facility.

The council told him to design one that was fully solar powered and that could serve as a training ground for wastewater-treatment professionals and high school students.

Construction is planned to start in about a year.

A visitor might be able to have a window into water treatment at every level, from raw sewage to finished treated water.

Cottonwood does a number of events with local schoolchildren, thinking they'll establish water conservation at home and as adults.

Having a number of locals visit the wastewater treatment plant as children and high schoolers will also help the city win the public's support if it ever taps the plant's output for drinking water, Lueder said.

Lueder recently got a call from one parent saying the city's program on water conservation stuck too firmly for one fourth-grader.

"I want to thank you for teaching my kid about water, but he's turned into the water police," said the father. "If I leave the faucet running while I'm shaving, he comes in and yells at me to turn it off."