PC Construction is proud to be underway on a major infrastructure upgrade for the AlexRenew Water Resource Recovery Facility (WRRF) in Alexandria, Virginia, a facility that serves more than 300,000 residents and treats roughly 38 million gallons of wastewater every day. The Solids Upgrade Program is a centerpiece of AlexRenew’s 20-year master plan.
The project touches nearly every aspect of the solids handling process, including:
- Replacement of four sludge heat exchangers
- Rehabilitation of existing digesters and three gravity thickeners, with a new scum collector system
- Installation of five thickening centrifuges and one dewatering centrifuge
- A new polymer system and 500-gallon water heater
- New mixers for the sludge blending and equalization tanks
- Demolition of the existing pre-pasteurization and lime systems
- Electrical upgrades to support all new equipment
PC’s team hit the ground running during preconstruction — completing demolition of the existing lime system, installing pilot mixers, and setting the new sludge heat exchangers. The work has been technically demanding, and a few early wins are worth highlighting.
- Gas valve replacement under live conditions. The owner couldn’t shut off gas in one of their buildings because 18 mixing compressor and safety shutoff valves were stuck open. In an emergency, that’s a serious problem. PC’s site team worked with our Special Projects Group to develop an extensive plan to manage the safety challenges: continuous flammability monitoring, high-volume ventilation, and a process that allowed for sequential isolation of each pipe segment using nitrogen gas to control atmospheric methane. Over two days, the combined crew methodically purged gas from alternating ends to safely displace it while replacing each valve one at a time, on a tight schedule, with no impact to operations. The owner said it best: “We are honored to have witnessed the exemplary skills, workmanship, and teamwork within the PC Construction team during the execution of this critical work.”
- Piping demolition and replacement. To demolish existing failing pipe, the team first installed 300 feet of temporary 6-inch hot water supply and return lines to maintain service. Once demolition was complete, they installed the permanent replacement: 250 feet of 6-inch pipe and 300 feet of 4-inch pipe, totaling just over 400 welds and 300 mechanical joints. Not a single leak.
- One day to solve what others couldn’t in ten. The owner needed a gas line purged to install two new valves. Multiple contractors had tried and failed over ten days. PC’s crew assessed the situation quickly and identified the problem: the gas was heavy, and the other contractors had been trying to push it uphill. PC pushed it downhill instead. The purge and both valve installations were done in a single day.
I could not be more impressed with this team, and these early wins set the stage for the primary construction phase beginning this fall. Full project completion scheduled for 2029.
Projects like this one are why I love this work. AlexRenew isn’t just a client — they’re a community partner with a real mission, and it’s a privilege to help them deliver on it.
Photos: Gas valve replacement in progress.