November 1, 2018
WORLD’S LARGEST PERKFILTER® INSTALLATION COMPLETED IN JUST FOUR DAYS
The city of Redmond, Washington needed a regional stormwater treatment facility capable of handling up to 20 CFS (cubic feet per second) or 9,000 gpm (gallons per minute). After contracting with IMCO Construction in Bellingham, Washington and Leidos Engineering in Auburn, Washington, the city settled on the revolutionary PerkFilter® media filtration system from Oldcastle® Infrastructure.
Media filtration products provide stormwater filtration to reduce pollutant loading in runoff from urban developments. Impervious surfaces and other urban and suburban landscapes generate a variety of contaminants that can enter stormwater, polluting downstream receiving waters. PerkFilter media filtration systems feature pre-treatment chambers and replaceable filter cartridges to capture and retain sediment, petroleum hydrocarbons, phosphorus, metals and other target constituents close to the source to reduce the total downstream discharge load.
DESIGN FLEXIBILITY
PerkFilter media filtration solutions are available in multiple configurations, including catch basins, vaults and manholes, allowing the engineer maximum design flexibility. The city of Redmond selected a continuous precast vault design, measuring 16’ high by 214’ long, and including 547 sets of stacked 12” and 18” replaceable PerkFilter cartridges.
Production of the precast concrete vault started in mid-October, 2014 at the Oldcastle plant in nearby Auburn, Washington. Both sizes of stackable PerkFilter cartridges were produced at the Oldcastle facility in Santa Rosa, California, then shipped north to Washington. Onsite assembly in Redmond quickly followed on December 8th and final installation was completed just three short days later on December 11th with the use of a crane to help expedite installation time.
Deon Lourens, Area Technical Manager with Oldcastle Infrastructure, explained that there are several advantages to the PerkFilter system. “Its cartridges have no moving parts and no cartridge hood, allowing for easier maintenance observation. In addition, its design allows for fewer cartridges than alternative models, and the bypass flow underneath the cartridge bay limits reentrainment of pollutants.”
He noted that cartridge lifecycle can range up to three years, depending on the pollutant load. “The cleaner the influent,” he said, “the longer the duration between maintenance cycles.”