Gold Hard Hat Award

Plum Creek Wastewater Authority Wastewater Treatment Plant #1
Submitted by: Rothberg Tamburini Winsor

RTW designed and implemented an innovative and low cost solution to expand the existing organic treatment capacity of the Plum Creek Wastewater Authority. RTW increased the capacity of the facility by more than 40 percent, which will meet the future needs of the community, and saved an estimated $150,000 in annual costs.

At maximum capacity, PCWA's existing plant needed to be expanded quickly to prevent violation of the EPA's wastewater discharge permit. RTW implemented the innovative step-feed process to increase the plant capacity without the addition of another aeration basin.

Instead, the existing return activated sludge mix basin was divided into a new influent distribution basin and a modified smaller RAS mix basin by building an internal wall. Two new weirs were installed to distribute the wastewater equally between between aeration basins #4 and #1 and #2.

While the step-feed process was being initiated, it was imperative that PCWA was fully functional and able to serve the community's current needs. Temporary bypass piping was utilized to keep wastewater flowing while design work was done on the aeration basin, and broad flow gates were installed to accommodate future flow rates.

In addition to increasing capacity with the step-feed process, RTW designed and coordinated pilot testing and construction of a temporary high-solids centrifuge in the existing solids processing building three years ahead of schedule of the permanent installation. By implementing RTW's solution, the PCWA was able to reduce the biosolids volume by 75 percent. This dramatically decreased the cost of transporting the biosolids that must be removed from the facility.

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