By David Chircop, Herald Writer
EVERETT -- It looked like a nearly mile-long snake, slithering across the Snohomish River and Port Gardner on Wednesday afternoon.
In reality, it was a massive high-density polyethylene pipe with cement collars being towed from Everett to Point Wells near Shoreline.
The pipe is a key piece of the $1.8 billion Brightwater project near Maltby that aims to treat sewage for people living in King and south Snohomish counties. The pipe, now filled with air to float, will later be sunk to the bottom of Puget Sound. It will be part of a system that will expel up to 36 million gallons of treated wastewater each day.
Treated sewage is dumped into the sea through what is known as outfall. This particular pipe will be sunk to a depth of 600 feet.
"This will be one of the deepest outfalls in the world," said Gunars Sreibers, Brightwater project manager.
The wastewater dumped into Puget Sound should be safe because it will be treated to the state's highest standards, said King County spokeswoman Annie Kolb-Nelson. By dumping so deeply, the waste is expected to be diluted even more and will be away from most marine life, which lives at shallower depths.
Additionally, the Point Wells site was selected because the currents are expected to push the wastewater out to the ocean and not further into Puget Sound, Kolb-Nelson said.
Crews had been assembling the 63-inch-diameter pipe for weeks at the Riverside Business Park near Highway 529. On Monday, they pulled the pipe with four tugboats down the Snohomish River and towed it into Port Gardner, heading south.
"This is the longest thing I've ever seen towed," said Dave Wetzel, a dispatcher for Dunlop Towing Co., based in La Conner.
The tugboat pulled the pipe at a gentle rate of 1 knot per hour -- a little faster than a mile per hour -- and it wasn't expected to reach its destination 14 miles away at Point Wells until 4 a.m.
Timing on the operation was crucial, because the tugboat operators could only safely navigate near the Highway 529 and I-5 bridges while the incoming tide and the river currents were nearly canceling each other out, providing maximum control for the tugboat operators.
A second massive pipe is expected to be pulled along the same route today.
Later this week, Foss Maritime, a Seattle based tugboat company, will straighten out the two pipes and form them into the shape of a Y and sink the pipes on the sea floor.
Brightwater is a giant sewer treatment plant being built by King County. It is expected to be operational by 2011. A 13-mile-long tunnel is being drilled from Maltby to Point Wells to connect to the polyethylene pipes.
In addition to these pipes, King County expects to build a second line to carry millions of lines of treated wastewater to irrigate landscaping and for industrial uses.
Reporter David Chircop: 425-339-3429 or dchircop@heraldnet.com.
