- ENGINEERING INFO
- CASE STUDIES
The Redbud Power Plant located just outside of Luther, Oklahoma is a high-efficiency, natural gas-fueled power plant that produces 1,230 MW of electricity. Since coming online in 2004, the power plant has used up to 11 million gallons per day of treated wastewater for cooling its turbines. The cooling water is provided by Oklahoma City through a 24-inch pipeline that travels approximately ten miles from the North Canadian Wastewater Treatment Plant to the Redbud Power Plant. The treated wastewater is a critical operating component of the power plant and has the added benefit of recycling water that would otherwise be discharged into the Canadian River.
On April 22, 2015, Oklahoma City Water Utility Trust (OCWUT) staff discovered a leak along the 24-inch steel line in the area where it crosses Deep Fork Creek, approximately two miles south of the power plant. Based on the inability to take the line out of service and the difficulty of repairing the line at a depth of 40 feet below the bottom of the creek, constructing a permanent replacement crossing on an emergency basis was deemed the best course of action.
OCWUT issued an Emergency Repair Proposal late on Thursday, April 23rd, with a mandatory site visit scheduled for 9:00 a.m. on April 24th. Bids were due at 4:00 p.m. that same day. The bid specifications, including subsequent clarifications, required installation of approximately 1,460 LF of 24-inch thermoplastic pipe (PVC or HDPE), with the majority to be installed via horizontal directional drilling (HDD). Performance requirements dictated that the pipe have a minimum inside diameter of 22.7 inches and a minimum working pressure rating of 150 psi. In addition, the pipe had to be capable of meeting the installation forces associated with a 1,400-foot directional drill at a depth of approximately 50 feet below ground level. Furthermore, because the pipe was carrying reclaimed water it had to be purple, green or white in color. Blue pipe was specifically excluded to avoid confusion with potable water.
Based on the performance requirements, Underground Solutions proposed 24-inch DR21 green Fusible PVC® pipe, which was in stock and available for immediate delivery. To meet inside diameter and pressure requirements, HDPE pipe was required to be 30-inch DR11, which required a significantly larger borehole for installation.
McKee Utility Contractors of Prague, Oklahoma was the low bidder and was awarded the contract. Shane McKee stated, “Based on the total installed cost, and the ability of Underground Solutions to perform under difficult conditions and within a compressed timeline, we selected Fusible PVC® pipe for the directional drill.”
McKee Utility Contractors subcontracted with Dolan Directional Drilling to perform the HDD portion of the project. Dolan had previous experience installing Fusible PVC® pipe, as well as the technical capabilities and equipment to complete a project of this size and length.
|Pipeline Details and Project Summary|
|Project:||Emergency 24-inch Reuse Line Replacement|
|Pipe Size:||24” DR21 FPVC®|
|Pressure Test:||150 psi|
|Owner/Engineer:||Oklahoma City Water Utility Trust|
|General Contractor:||McKee Utility Contractors|
|HDD Contractor:||Dolan Directional Drilling|
The project moved extremely fast despite record setting amounts of rain that fell in the Oklahoma City area during the construction period. Pipe was pulled-in on Saturday, May 16th, by Dolan Directional Drilling in what is best described as the culmination of a well-executed plan under difficult circumstances. The entire project was initiated, bid, awarded, installed, reconnected, and brought into service in less than four weeks.