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Town Branch WWTP Controls Odors with Modular Covers

Covers help maintain a more consistent temperature while minimizing odors

The Town Branch Wastewater Treatment Plant located in Lexington, Kentucky, USA, serves a population of 130,000—about 60% of Lexington—Fayette County. The plant began operating in 1919, and currently treats almost 11 billion gallons of wastewater annually.


The Town Branch Wastewater Treatment Plant needed to replace failing steel-dome gas collecting covers. This meant converting four existing tanks, which included a blending tank, two secondary digesters, and a side-stream holding tank.

With the changes taking place, the plant knew it would need an odor control solution and something to help maintain a more consistent temperature throughout the year without having to add heat. J Dwight Thompson Company, Evoqua’s Geomembrane Technologies area representative specializing in municipal and industrial water and wastewater process equipment, suggested the plant consider re-covering the tanks to minimize odors, but with a more economical product.


Evoqua’s Geomembrane Technologies was selected to fabricate and install custom-fit, insulated modular covers each sized between 44 ft and 46 ft (13.4 m and 14 m) in diameter for the four tanks at the Town Branch Wastewater Treatment Plant.

The durable modular cover design allows individual panels, also known as modules, to be removed and replaced for routine maintenance. Each panel has additional support along the edges, meaning the covers are safe to walk on in any location—even when panels are removed.

The covers were tailored to fit around central floating mixers in each tank, so there is no upwelling. They float freely in the tanks, rising up and down as water levels change. The covers were installed without interfering with plant operation, or needing to drain existing water within the tanks.


The covers Evoqua’s Geomembrane Technologies custom-fabricated for the Town Branch Wastewater Treatment Plant are functioning very well, and plant operators and management are pleased with the results. Odors are effectively controlled at the facility, thus maintaining community relations and worker satisfaction.