American Council of Engineering Companies Award - Trinity River Authority Grit Project

Awarded By - American Council of Engineering Companies

One of the largest wastewater treatment facilities in Texas, The Trinity River Authority’s Central Regional Wastewater Treatment Plant (CRWS) is centrally located in the Dallas/Fort Worth Metroplex. Through the use of innovative technologies the CRWS has provided superior wastewater treatment to this vast population while minimizing odor impact to neighboring homes and businesses and by reducing overall costs to its member cities. However, as the CRWS service area continued to grow, the need to update and improve the plant system became more evident.

The CP&Y Team (comprised of CP&Y, Inc. and Alan Plummer Associates, Inc.) was contracted to design improvements for the phased improvements to the grit removal system at the CRWS to reduce odor emissions and increase capacity so that the peak plant grit removal capacity would accommodate future flow.

The final design of the system included the demolition of all ten existing aerated grit basins and the installation of five new 70-MGD vortex grit basins, six new grit pumps, and two new grit classification units, providing a total peak flow capacity of 350-MGD.

In a vortex grit basin, a vortex flow pattern is achieved using the natural hydraulics of the influent and a mechanical propeller located in the center of the vortex. Grit is forced to the center and settles via gravity to the cone of the basin. Grit pumps transport the grit slurry to the grit separation process, which includes two grit teacups removal units.

CP&Y met the goals of increasing the grit removal capacity of the Phase I/II treatment train and reducing the overall odor emissions of the plant with a design that also reduced overall capital of the project by 50%. This design also decreased the total connected energy load, reducing the annual energy cost of the treatment process by $106,000.