The City of Marble Falls had added a new clarifier to its water treatment plant a few years before this project and had reached a point where the original clarifier needed to function similarly to the newer equipment. The City of Marble Falls selected Trihydro to renovate its original water treatment plant clarifier. Upon inspection, Trihydro identified that the two clarifiers were not hydraulically balanced, and successful engineering renovations to the original clarifier would require implementing measures to operate the two clarifiers at the same hydraulic grade line (HGL).

The project involved installing two new high-service pumps to replace the existing pumps, which were rated +/- 1,000 gallons per minute (GPM) and started across the line. The new pumps are rated at +/- 2,400 GPM with variable frequency drive (VFD) controls to achieve high-service flow of 4,800 GPM. While the City of Marble Falls was able to operate with a single clarifier during low flow periods, developing and maintaining an expedited project schedule was of the essence so renovations would be complete for approaching periods of high demand.

During preliminary design, Trihydro conducted a field survey and interior examination to document existing structural issues that could adversely affect renovation. Trihydro also held discussions early on with equipment suppliers and contractors to coordinate the most expedient way to proceed with the clarifier renovation. Preliminary design involved collecting existing hydraulic data on the high-service pump station and calculating suction side hydraulics to determine if piping or structural issues would impact the ability to achieve the desired pumping capacity. For the discharge side, Trihydro calculated the average and peak total dynamic head (TDH) for the two new pumps and for the entire pump station to select pump sizing. The preliminary design phase also entailed overseeing supervisory controls and data acquisition (SCADA) configuration while keeping the Texas Commission on Environmental Quality (TCEQ) informed of the project’s progression to support streamlined reviews and approvals in later project phases.

With the final design delivered and approved on time, Trihydro moved on to bidding the project for construction and providing a recommendation on award. After the City Council approved the construction contract, Trihydro oversaw the on-time and on-schedule clarifier renovation, allowing the City of Marble Falls to continue providing high-quality, reliable service to its customers.