Leeds, Alabama

In the heart of Alabama, where the counties of Shelby, Jefferson, and St. Clair intersect, sits the town of Leeds, birthplace of basketball legend Charles Barkley. Flowing right through town is the Little Cahaba River, which places the municipality within the Mobile River basin. This system of rivers flow into the Gulf of Mexico, where the nutrients they pick up contribute to one of the largest dead zones in the world.

But even before those nutrients hit the Gulf, effluent ammonia that might flow from a wastewater treatment plant can have a disastrous impact on the local ecosystem, and with all 194 miles of the Cahaba River flowing within the Alabama’s borders, the need for Leeds to protect this local jewel becomes clear.

Located 20 minutes’ drive due east of the state’s biggest city, Leeds’ development as a Birmingham bedroom community is dependent in part on available wastewater treatment. With its existing biofilter system approaching its design capacity, Leeds’ treatment plant showed signs it could no longer be counted on to fully nitrify. But beyond ensuring the plant could reliably meet its regulatory limits and retain dissolved oxygen in the effluent, Leeds’ plant operators were presented with a pair of challenges from the site itself. Most prominently, the site’s lack of available footprint meant any new process technologies would have to fit within its existing space. Furthermore, the site’s residential-scale, single-phase electrical supply meant that common, industrial- or municipal-scale equipment wouldn’t be able to run. With those challenges in mind, plant managers went looking for a solution.