Designing a Single Wastewater Plant to Serve Two Communities

Award-Winning Project


The City of Box Elder and the Ellsworth Air Force Base were each operating their wastewater treatment facilities at capacity and had to satisfy more stringent effluent limits for ammonia. Both entities needed wastewater treatment facility upgrades. And they needed to find the most cost effective way to do it.


A new wastewater plant was designed to satisfy the regulatory requirements and future growth accommodations for both the City and the Air Force Base. The single wastewater treatment plant serving both the City and the Base resulted in a $10 million savings over creating single plants for each.


  • 3 million gallons per day design flow
  • 9.3 million gallons per day peak flow
  • Sequencing batch reactor process


  • 2016 Outstanding Engineering Achievement Award | South Dakota Engineering Society - Eastern Chapter (SDES)

Box Elder Wastewater Treatment Facility

Box Elder, S.D.

South Dakota Ellsworth Development Authority


  • Preliminary Design
  • Final Design