Xcel conserves with effluent: Amarillo sewage water helps produce energy

Second Time Around: Treated wastewater pours into a holding lagoon at the Nichols and Harrington power plants. Xcel uses 5 billion gallons of wastewater a year in the powerplant cooling system.

March 26, 2004

The city of Amarillo and Southwestern Public Service Co., now Xcel Energy, realized long ago water was a precious commodity - one worth conserving.

The two entities joined forces almost 45 years ago on a project that ships sewage water from the River Road wastewater plant to the Nichols Station power plant, where it is utilized to help produce power there and at Harrington Station.

As fresh water supplies are becoming limited and demand is increasing, Xcel Energy officials are being sought out to share their technology and expertise with other industries and other cities.

Production of electricity at power plants requires a lot of water, but every year Xcel Energy substitutes about 5 billion gallons of specially treated Amarillo and Lubbock sewage water to power its three stations, said Bill Crenshaw, Xcel spokesman.

'There's a great concern in this region about the long-term sustainability of our water," Crenshaw said. "We've been working for decades to maintain those long-term supplies."

Nichols Station laboratory supervisor Bernie Wieck, who oversees chemical treatment of the effluent so it can be used at the plants, said substituting the sewage effluent at the plants conserves enough fresh water to supply the yearly needs of 100,000 people.

And Wieck said they can purchase the effluent for 16 cents per 1,000 gallons, compared to 82 cents per 1,000 gallons if it was purchased as fresh water from the Canadian River Municipal Water Authority or $1.25 per 1,000 gallons from the city of Amarillo's well fields, which is only used in emergency cases.

Dan Coffey, city of Amarillo director of utilities, said the city started selling effluent in the mid-1950s to the Texaco refinery, but in 1959, the city built its first pipeline to Nichols Station.

Today, Coffey said, the city sells most of the water treated at the River Road plant, the city's largest waste water plant, to Xcel.

"Otherwise we would be discharging the water into the creek," Coffey said. "It's a water-conservation issue. SPS would have had to gotten water for their cooling towers from wells or another source. This way you are using the water for a beneficial purpose."

He said when Amarillo started selling its effluent, it was truly a leader.

"We've had other cities come to us about how we set it up, the treatment and the technical issues involved," Coffey said.

"There are more and more cities trying to use their effluent," he said. "It's becoming a more valuable commodity as demand for water in the world increases. The availability of fresh water is limited and the demand is greater, and reclaimed water is a good application for cities in certain situations."

For Xcel, which provides electricity to 1 million people in a 52,000-square-mile region - a process that requires almost 350 million gallons of water daily - it's a good application.

Nichols power plant design engineers, production personnel and environmentalists have pioneered chemical treatment and other technologies over the years that allow more and more re-use of the reclaimed sewage water, Crenshaw said.

A major step was utilizing lime to remove phosphates from the water, which had created a scaling problem at the Texaco plant, Wieck said. After experimenting with amounts, it was determined 1.5 pounds of lime per 1,000 gallons of treated water was needed.

When water comes from the River Road facility, it is put into clarifiers where lime is added and then it goes into a settling zone and into the makeup lagoons, he said.

Approximately 350 million gallons of water a day are circulated through all the towers. About 8 million gallons are lost daily to evaporation and another 3 million is sent to irrigation, so the missing 11 million gallons is resupplied daily from the makeup lagoons or effluent water, Wieck said.

The water can be circulated hundreds of times as cooling-tower water and when it is no longer usable for that purpose because of high salt content, much of it can be further recycled as irrigation water for nearby grass pastures, he said.