Over the last few years, Headworks® has provided two Bar Screens under two separate contracts to the City of Everett, Washington at the Everett Water Pollution Control Facility. The Everett WPCF had previously been equipped with three coarse climbing screens. Planning a screenings system upgrade several years ago, the City of Everett staff reviewed all available technology’s abilities to meet their objectives of providing finer screening for a wide range of combined sewer and storm flows. “EWPCF peak day flows can exceed 90 MGD, nearly seven times its ADWF, with peak instantaneous flows reaching 200 MGD!” (Charles Johnstone Everett WPCF, 3 June 2004). They selected the durable Headworks® Bar Screen in 2001, which provides fine screening as well as greater flow capacity than its competition. The Headworks® Bar Screen was chosen also because it fit well into the existing system’s footprint and line of conveyance.
The climbing screens, installed in 1984, were originally supplied with a bar spacing of 3/4”. As service area flows increased over the years, the slow cleaning interval of the single-rake climber screens caused frequent screenings system bypasses. Prior to the installation of the Headworks® Bar Screen, it was necessary to open a second screening channel, when the first channel reached the flow rate of 30 mgd. The Headworks Bar Screen with 1/3 the bar space opening was able to process the amount of flow through a single channel flows previously requiring double the channels and equipment. The 1/4″ bar spacing with a maximum channel depth of only six feet gave the plant 60 mgd of screening capacity in one channel.
After reviewing the competition, the city and their engineering consultant from Brown & Caldwell came to the conclusion that Headworks® screening technology was the only technology that QUALITY THAT NEVER QUITS™ would meet their unique needs. The specifications for the project replaced the standard “or equal” clause with a sentence indicating that the City of Everett knows of no equal to the Headworks® Bar Screen. Since its installation in June of 2001, the City has been very pleased with the Headworks® screen design, performance, and minimal maintenance requirements. The City installed their second Headworks® Bar Screen in 2003.
The Headworks® Screen proved its worth as a true workhorse offering durability and high performance to the City of Everett and the operating personnel at the Everett Water Pollution Control Facility, eliminating operational challenges during peak flow periods.
