Street sludge has a new home
June 9, 2008 · Updated 6:20 PM
The city moves its decant operations to a state-of-the-art facility at Vincent Road.
The citys relocated and newly built decant facility at the Vincent Road transfer station incorporates new technologies to filter, clean and dispose of the grit, sludge and noxious chemicals that collect on island roads and can trickle into waterways.
Its really a premier facility, said Lorenz Eber, an engineer with the citys Department of Public Works who led development of the new decant operation. Its the most state-of-the-art in the county, maybe even the state.
The $1.3 million facility, now fully operational, will replace the existing decant operation at the citys Head of the Bay property next month.
The old site drew fire from neighbors and environmentalists who charged that the facility contaminated Cooper Creek and nearby wetlands and threatened wells serving Winslow residents.
Prompted by a complaint from an Eagle Harbor Drive resident, the Kitsap County Health District in 2003 determined that the contaminated roadside material posed an unacceptable threat to the citys wellheads, which are located downhill from the original decant facility. Almost 8,000 tons of material were removed from the Head of the Bay site by the city in accordance with health district orders.
Island resident Dan Brewer sued the city in the spring of 2004 to halt the facilitys activities. The city and Brewer settled out of court last year, with the city agreeing to move the facility and halt all public works activities at the site within five years.
The new decant site on Vincent Road, which borders the waste recycling operations managed by Bainbridge Disposal, will officially open with a ceremony on April 14.
We hope to have the mayor dump the first load, said Eber. Maybe well have her drive one of the street sweepers, one of those big trucks. Well have to train her first.
The new facility sends sludge gathered from street sweeping, ditch cleaning and storm drain clearing through a half dozen filtration and separation processes.
What we get from the street sweepers and catch basins is contaminated, but its not nuclear waste, Eber said. Its basically the stuff you sweep up in your garage pine needles, motor oil, break pad shavings, leaves.
With a consistency similar to lentil soup, the mixture is deposited in a large concrete bathtub where road wastes drain and dry out.
The water draining from the solid waste looks a lot like tea at this point, according to Eber.
This brackish brew is sent though an oil separator before funneling through a sand filter.
The clarified water will drain into a bioswale trench with grasses to provide natural filtration.
More (waste) gets hung up on the blades of grass, filtered kind of like the teeth of a baleen whale, said Eber.
Water is finally transferred to a detention pond that receives regular cleanings.
The entire process takes between three days to just over one week, Eber said. The solid wastes, which contain motor oils, arsenic and heavy metals, are collected and sent to landfills.
This saves us money, said Eber. By draining it, it weighs much less in pounds when we send it to the landfill.
The facility was modeled after decant operations in Purdy, Renton and Kitsap Countys facility in Brownsville.
We looked at the Brownsville one a lot and made some improvements on it, said Eber. The Brownsville one was probably the premier facility in the state but ours is like the Mark II of Brownsville.
Future upgrades could include road gravel recycling and the composting of some organic matter, according to public works staff.
Its a very exciting facility, said Lance Newkirk, the assistant director of public works. The structure of it may allow us to look at additional equipment that will allow us to screen material and recover some of the gravel to reuse on roads.
The original island decant facility was established under the mandates of new state and federal environmental laws.
Decanting facilities are a new art, said Eber. They came out of stricter regulations to keep Puget Sound clean and have only been around for 10 years. Were learning new things as we go.
Its unclear what the city will do with the original facility.
Our initial activity will be to demobilize the operation, Newkirk said. The city then has a lot of options to explore (for the site), which will be vetted in the public policy arena.
The settlement reached with Brewer restricts city uses of the site, while a number of wellheads could constrain residential development, said Brewers lawyer Ryan Vancil.
During the settlement process, the city hinted that the property could be set aside as open space, said Vancil, an island resident working for a Seattle firm specializing in environmental law.
Everyone was looking at that as the likely outcome, he said, adding that the property borders other recent open space acquisitions, including the Hidden Valley Trail property.
Vancil said the new decant facility is a step in the right direction.
I think its great, he said. Its the best thing that could be happening. The city acknowledged that the Head of the Bay was not the best place (and) is learning to deal with these materials appropriately.