Bartlesville may never have to reuse its wastewater effluent as a supplement to its water supply, but the city is prepared if the need arises.

Its plan to pipe a portion of the effluent upstream of the raw water intake in the Caney River won an award from the Oklahoma Water Resources Board. In January it received a U.S. EPA George F. Ames PISCES Award for excellence in problem-solving, one of five PISCES awards presented in 2022.

The possibility of water shortages during drought is a chronic concern in the region. Bartlesville draws its entire water supply from a large flood-control lake developed by the U.S. Army Corps of Engineers, a smaller lake, and the Caney River, which flows through the city. The storage capacity of the lakes is diminishing because of sedimentation, says Terry Lauritsen, water utilities director.

“We’ve had times when water has been abundant, and we’ve had times when water is very, very scarce,” Lauritsen says. “The intent is for a contingency water supply, so during a drought or some other condition where our lakes are unavailable or compromised, or whatever the scenario may be, we can divert treated wastewater to the river. That gives us another 4 mgd on top of the natural flows of the river as a supplementary raw water source.”

The project involves building a pipeline to pump effluent seven miles upstream from the water treatment plant. In addition, the work includes an outfall on the riverbank and improvements to a pump station, along with some modifications to the wastewater treatment plant (20 mgd design, 7.5 mgd average flow).

Effluent would be pumped upstream only in times of need. “If we don’t need the water, then we don’t need to incur the expense to move that water upstream on the river,” Lauritsen says.

Long mixing time

The discharge point for the effluent is near a bridge; it was selected for ease of maintenance and for distance from the water plant intake.

“What ultimately drove it was the road network and how that crosses the river,” Lauritsen says. “We wanted to keep that pipeline close to a road. It makes it easier to monitor, and if any maintenance or other work is needed, the location makes it simpler.

“The other part is we wanted to build enough of a buffer. It’s a pretty slow-moving river. Under normal flow when we’re discharging, it would take several days for that water to get down to where we would pull it out of the river again. It facilitates a good mix with the river.”

The distance from the intake also gives the utility time to react if an incident at the wastewater treatment plant should cause temporary concern about reusing the effluent. “It gives us some time to turn off the pump station and gives us some extra safety in case that kind of a scenario comes up,” Lauritsen says. 

First in the state

The project is estimated to cost $8.2 million. The city is using grants and low-interest loans from the Oklahoma Water Resources Board’s State Revolving Fund to pay for the project. Bartlesville is the first utility in the state to build this type of water reuse project.

“The challenges are that we are the first in Oklahoma to even proceed with the concept of the project,” Lauritsen says. “It has taken a collaborative effort with the Oklahoma Department of Environmental Quality and consultants to build a consensus of support with our constituents. We’ve been talking about water reuse since 2015 with whoever would listen.”

The region experienced a severe drought in 2001, when the city’s reservoir sources were depleted to about 20% of the normal volume.

“It was scary,” Lauritsen says. “The city council was going to consider some onerous water restrictions, but the week before they met, we had a 6-inch rain in the watershed. A few weeks later we had another 6-inch rain, and we filled the lakes back up in less than a month.

“We had been in a drought for nine months to a year up to that point, and it was replenished in less than four weeks. It took some drastic weather conditions to replenish that. It was a wakeup call telling us we needed to do something to look at long-term water supply.”

The next frontier

The Water for 2060 Act, which state legislature passed in 2012, encourages communities to develop plans to consume no more freshwater in 2060 than in 2012.

“That opened up reuse scenarios — not only industrial and irrigation applications but also potable use. Indirect potable use is the angle we are pursuing. It’s not an end-all solution, but it buys us a lot of time to look at area lakes or other sources of water that we could possibly reclaim to replace the storage we’ve lost to sedimentation.”

Lauritsen thinks other area communities facing similar losses of storage capacity in flood control lakes built in 60 or more years ago will consider indirect potable reuse projects.

“Water reuse is the next frontier. Historically we have been very rich in water supply in lakes, but the lakes close to us were built in the 1950s and 1960s. They are losing a lot of water storage space. Reuse is a very feasible option when you compare it to the huge capital costs to dredge a lake or build a new lake.”