Circular Clarifier Retrofit Significantly Improves Flow Rate at Arkansas Plant

The Benton/Washington Regional Public Water Authority (PWA) located in Rogers, Arkansas, provides drinking water to various municipalities and rural communities in Arkansas, Oklahoma, and Missouri. Unable to meet the 6 MGD design flow rate of clarifiers, the plant turned to the Meurer Research team for assistance. Over the past few years, Benton/Washington worked with MRI, Crist Engineers and our representative, Environmental Technical Sales (ETEC), to retrofit / update two existing 78’ diameter solids contact clarifier basins by installing MRI Inclined Plate Settlers. The retrofit of circular clarifiers with inclined plates is not common, but the team was able to come up with a design that worked well to meet the space requirements and needs of the plant.

In 2021, a total of forty-four 304 stainless steel MRI plate cartridges were installed along with 22 shared effluent troughs. The shared trough design, which is unique to MRI, made it possible for MRI to supply plates in a circular clarifier. Two rows of cartridges share each trough, which limits the number of troughs and wall penetrations and significantly reduces capital costs and installation costs. Additionally, the shared trough design helps save space which is usually tight feeding effluent to the center of circular clarifiers.

Chad Cooley, a sales representative from ETEC, reported that since the installation of MRI’s plate settlers, “The engineer said the solids contact clarifiers are producing more water, and with better quality, than ever before."

With MRI’s Inclined Plate Settlers now installed and operational, the plant can operate at the original requirement of 6 MGD and even up to a peak flow of 8 MGD with future planned peak demand.