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Oklahoma City maximizes use of its water resources
With water supplies always top of mind in the face of regional scarcity challenges, Oklahoma City officials sought a way to continue to provide safe, reliable water service to residents and businesses while making the most of the city’s water resources. In 1996, the city decided to begin offering recycled water to its large industrial water users. This required working closely with Veolia Water, the city’s wastewater treatment partner, to determine the treatment levels needed and to construct a delivery system to transport the recycled water to customers.
The city’s customer base began with Gaillardia Country Club and expanded to include two local utilities soon after. In Oklahoma City, the decision to offer recycled water to area businesses not only would save participating businesses money, it also would reduce the amount of potable water consumed for industrial purposes.
Today, three out of Oklahoma City’s four wastewater treatment facilities can deliver recycled water to industrial customers. Together, these three facilities produce approximately 15 million gal of recycled water per day (mgd), saving the city more than 1 billion gal of drinking water annually.
Oklahoma City Treatment
Since 1984, Veolia Water has been working with Oklahoma City to manage its 80-mgd tertiary activated sludge wastewater treatment plant. In 1988, the company added to its efforts the management of the city’s 10-mgd tertiary activated sludge plant, 15-mgd rotating biological contactor activated sludge plant and 75-mgd Witcher Pump Station. Finally, in 1991, Veolia Water was granted management of the remaining large wastewater treatment plant that Oklahoma City owned: a 6-mgd sequencing batch reactor plant. In all, the plants can process a combined 106 mgd of residential and commercial wastewater in a cost-effective manner. Under the terms of the partnership, the city’s municipal wastewater treatment facilities provide recycled water to area businesses.
While the majority of the treated effluent is discharged into nearby waterways—including Deer Creek, the North Canadian River and the South Canadian River—up to 22% of the total incoming wastewater to all of the facilities that Veolia operates is recycled and reused by area businesses. Recycled water can be treated to meet a number of requirement levels, ranging from secondary-level treatment water that can be used in the cooling towers at local electric companies to advanced treatment for irrigating the local Gaillardia golf course.
The History of the Recycled Water Project
The Gaillardia Country Club was the first customer to begin receiving recycled wastewater from the Deer Creek wastewater treatment facility in 1996. Not long before, the city informed the Gaillardia community that it could not provide potable water for the golf course. The country club tried drilling wells to supply water for the golf course, but quickly realized that was not a sustainable option. The country club looked to the city to determine its other options.
Working alongside Veolia Water, the city offered recycled water as an option for the golf course. To receive the water, it was determined that a 5-mile pipeline would have to be built from the wastewater facility to the golf course. Today, up to 3 mgd of treated effluent can travel through this pipeline from the Deer Creek facility to the golf course, where it is used to irrigate more than 600 acres of greens and landscaped property.
Given the success of the first recycled wastewater delivery, Oklahoma City expanded its capabilities to the North and South Canadian River wastewater treatment plants. In 2003, when the new Redbud electrical company decided to locate its operations outside Luther, Okla., it approached Oklahoma City and Veolia Water to design a system that would utilize the discharge of the North Canadian facility for their cooling towers. In 2004, OG&E determined that they wanted to transition their operations from using potable water to recycled water. They approached Oklahoma City and Veolia Water about utilizing the South Canadian plant discharge.
In both instances, the utilities built the pipelines needed to receive the treated effluent. OG&E built a two-mile pipeline from the South Canadian facility to their operations. OG&E also built a large holding tank for treated effluent. Redbud built a 10-mile pipeline from the North Canadian facility to their operations. By building the pipelines, these one-way “side streams” ensure that the recycled water stays separate from the municipal drinking water, as well as the wastewater collection. Together, these two customers use approximately 13 mgd of recycled water everyday for their cooling towers.
How It Works
For the most part, Veolia Water can meet Oklahoma City’s customers’ recycled water needs by relying on the existing wastewater treatment equipment. Both OG&E and Redbud require standard-level treated effluent for use in their cooling towers. The recycled water for Redbud is chlorinated on site, whereas OG&E further treats the water with chlorine and other processes once it is received through the pipeline.
Recently, due to changes in regulatory requirements, Gaillardia Country Club asked Oklahoma City and Veolia Water to upgrade the Deer Creek facility to include new ultraviolet (UV) treatment technology. The UV treatment produces recycled water at a higher-purity level. Veolia Water installed UV vessels containing approximately 30 UV lamps per vessel.
Given the success and cost benefits of these three water reuse programs, it is not hard to convince local business owners to start using recycled water. Oklahoma City’s recycled water sells for a fraction of the price of potable water.
The golf course sees even greater savings. Because the recycled water that they purchase is not treated to the same levels as potable water, it contains some nutrients at a higher level than potable water. When applied to golf courses, the water actually serves as a fertilizer, too. This reduces the amount of money that the golf course spends on grass fertilizer, while conserving precious drinking water.
“Let’s be clear. If a golf course or utility isn’t using recycled water, it’s using drinking water,” said Patrick Corbett, Veolia Water project manager at the Oklahoma City wastewater treatment facility. “That’s expensive for the customer and puts water resources at risk.”
The growing interest from area businesses to purchase recycled water is helping local residents to save money, too. Because recycled water is not treated to the same quality as drinking water, fewer chemicals are used and less energy is consumed in the treatment process. This reduces the costs to ratepayers, who foot the cost of chemicals and energy in water and wastewater rates.
“It’s really a no-brainer,” Corbett said. “If a large water customer doesn’t need water treated to drinking-water quality, why spend ratepayer money treating it to that level?”
Oklahoma City would like to see more businesses in the region use recycled water due to the benefits it provides to a business’ bottom line, the environment and to ratepayers. The city also believes that increased recycled water usage from businesses can help spur development and growth because water resources are being used more wisely.
“Water reuse is the most sustainable and cost-effective solution for preserving our water resources,” Corbett added. “As the country becomes more and more water-stressed, the need and use of recycled water will be even more important.”