Clarksville Gas & Water needed a new water treatment plant to supplement their existing facility. Clarksville’s industrial growth over the last five years has been explosive and the associated potable water demands were projected to eclipse the existing facility’s capacity in under five years. SSR led a multidisciplinary team of professionals that included numerous subconsultant firms to accomplish the design quickly and efficiently.

Wanting to duplicate their existing plant as much as possible for ease of operations and maintenance, the new plant incorporates the same technologies as the existing plant including coagulation, flocculation, sedimentation, and membrane filtration. One notable difference between the two plants is the inclusion of pressurized GAC contactors downstream of the membranes.

Although the design of the North Clarksville Water Treatment Plant (NCWTP) treatment process was nearly identical to the existing plant, the source water between the two plants is slightly different. The new plant intake is located downstream of the confluence of another river and several combined sewer overflows from the City of Clarksville that the existing plant sits upstream of. Sampling was provided during the preliminary design of the plant and confirmed no substantial differences in the waters however the grab samples could only account for certain times and flows and thus provided some limited results. The installation of GAC provides additional treatment if variations in source waters are experienced that may result in operational changes between the two plants. During the preliminary sampling, no evidence of PFAS or other emerging contaminates were discovered, however regulation of PFAS in drinking water supplies appears to be imminent and other emerging organic chemical regulations are likely not far behind. In case PFAS or other emerging contaminants appear in the source water, the GAC contactors at the NCWTP will be ready to remove them.

The GAC pressure contactors at NCWTP will also provide additional Total Organic Carbon (TOC) and geosmin/MIB (2-methylisoberneol) removal. A unique design feature for the NCWTP to account for the lower geosmin/MIB levels when the winter months bring colder water temperatures, is a by-pass around the GAC units. This bypass will provide operational flexibility and extend the life of the carbon by removing the units online. When completed, the facility will assure that the City has an ample supply of highly treated potable water to provide to the industrial, commercial and residential customers for decades to come.