HDPE Pipe Plays Major Role In City’s Sewer Expansion

By Jeff Griffin, Senior Editor | September 2008 Vol. 63 No. 9

The city of Garland, TX, is in the process of a major sanitary sewer improvement program that will expand its capacity and improve conditions for this community of 230,000 located just northeast of Dallas.

The Duck Creek Interceptor and Transfer Line Project includes installation of 48 , 60 and 66 inch gravity pipe, a 48 inch transfer line, and an 8 inch sludge force main, said Brent Erickson, wastewater operations manager, Garland Water Utilities.

The new sewer lines link the city's Rowlett Wastewater Treatment Plant to the recently expanded Duck Creek Wastewater Treatment Plant.

"At build out, both plants had the capacity to process 40 million gallons per day (mgd)," said Erickson. "The Rowlett plant was landlocked and could not expand, so the decision was made to limit it to 24 mgd and transfer as much as 16 mgd to the Duck Creek WWTP.

Work on the $59 plus million project consists of three phases that include placement of approximately 25,000 linear feet of 48 inch outside diameter (OD) raw wastewater force main; 17,000 linear feet of 48 inch interceptor sewer; 15,500 feet of 60 inch interceptor sewer, 24,500 feet of 66 inch interceptor sewer and 65,000 feet of HDPE sludge force main.

First time

Erickson said the project was the first time 48 inch HDPE had been used by the city.

"The HDPE pipe is an important component in the overall scope of the project," said Erickson. "HDPE was selected because the fused joints provide less potential for leaks. It also offers lower surge potential, flexibility and internal and external corrosion resistance. Twenty five thousand feet of 48 inch HDPE was installed from the Rowlett WWTP to a junction box for gravity sewer. The other 17,000 feet of 48 inch pipe was Hobas pipe."

Oscar Renda Contracting, Roanoke, TX, is the general contractor. The supplier of the HDPE pipe, Gajeske Inc., Houston, was the subcontractor who fused the 48 inch HDPE pipe and 65,000 feet of 8 inch sludge force main HDPE pipe. The HDPE pipe used on the project was manufactured by Performance Pipe, a division of Chevron Phillips Chemical Co. The Hobas pipe was supplied by Houston-based Hobas Pipe USA.

Cut and cover construction is being used to install most of the pipe, said Erickson. Trench is being dug by two Caterpillar 383 excavators. Depths of trenches ranged from 7 to 25 feet.