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St. Clair County, Alabama

Coosa Valley Water Supply District Water Treatment Plant

6.0 MGD

GMC worked with four entities through the planning and development of a 3.0 MGD water treatment plant on the Coosa River with the ability to high rate to 6.0 MGD.

There are four entities that form the CVWSD which include the City of Pell City, Odenville Water Board, St. Clair County Commission and the City of Springhill.

Initial planning efforts included obtaining grant funding, process evaluation, conceptual design, budgeting, cost estimating, and reclassification of the river. The water treatment facility consists of a raw water intake with fixed screens on the Coosa River and an adjoining limestone quarry. This raw water source is unique because the quarry is fed by the Coosa River and acts somewhat as pre-treatment; however, CVWSD has the ability to utilize either for raw water.

Once the source is selected, water is then pumped through a static mixer and into a rapid mixer where chemicals are introduced. An upflow clarification (Superpulsator) is utilized for flocculation and sedimentation and three (3) multimedia filters with GAC are used prior to entering a 750,000-gallon clearwell before being conveyed to the distribution system with the finished water pump station. Other process components consisted of chemical feed systems, residuals handling, SCADA system, and laboratory and administration building.

The plant is rated at 3 MGD at a filter rate of 2 gpm/sf of filter area; however, the filters were sized to handle 4gpm/sf which equates to a plant capacity of 6 MGD. The site layout was designed such that the plant could be mirrored to then achieve 12 MGD.