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The City of Dallas, Georgia is the county seat of Paulding County. Located in the Atlanta metro area, Paulding is Georgia’s second fastest growing county. Recent population growth, coupled with forecasts for doubling in size over the next 20 years, led the City to retain Stevenson & Palmer Engineering, Inc. (SPE) to design a new wastewater transmission force main and gravity outfall to serve the Northside Wastewater Treatment Plant (WWTP).
The City’s utility staff and SPE engineers had to establish a route for a new 16-inch force main to transport wastewater from the existing Westside WWTP to a new regional WWTP to be constructed adjacent to the existing Northside WWTP. Plans called for converting the Westside facility to a pump station and conveying wastewater through the newly constructed force main to the new Northside treatment plant. Wastewater effluent would then be discharged via a new 24-inch gravity outfall to Pumpkinvine Creek.
The final design for the force main alignment involved nearly four miles of 16-inch pipe, with the majority of the line consisting of bell-and-spigot PVC pipe installed by open-cut. The design included a dozen trenchless sections with Fusible PVC® pipe installed by horizontal directional drill (HDD).
As SPE design engineer, Curtis Barber, P.E., explained: “HDD was specified for areas where restoration costs and public disruption associated with open-cut would have been significant. In other cases, narrow easements, creek crossings, and limited access made HDD the better installation approach. Fusible PVC® pipe was specified for the HDD sections because it provided equivalent flow area to the 16-inch bell-and-spigot PVC pipe and was compatible with the standard mechanical fittings used in the open-cut pipe installation.”
|Pipeline Details and Project Summary|
|Project:||Wastewater Transport System & Northside WWTP Outfall|
|Length/Size:||2,700 LF of 16-inch DR18 Fusible PVC® pipe|
|Installation:||HDD (12 bores)|
|Engineer:||Stevenson & Palmer Engineering, Inc.|
|Pressure Te:||150 psi|
|Installation:||HDD / Jack & Bore|
|Owner:||Hoosier Hills Regional Water District|
|Contractor:||Rockdale Pipeline, Inc. / Comtrac, Inc.|
Mr. Barber also noted: “Ultimately the contractor encountered some significant rock on the drills. Minimizing the borehole size by using Fusible PVC® pipe was a definite benefit. Everyone on the project was pleased with the performance of the pipe, as well as the field service support from Underground Solutions. We won’t hesitate to turn to Fusible PVC® pipe when needed on future projects.”