February 15, 2012

$35M wastewater plant upgrade good for Arlington, river, sound

Photo by Will Austin Photography [enlarge]

Arlington public works director Jim Kelly said the town uses water from the river and puts it back in downstream: “It’s cleaner than when it’s taken out.”

Arlington's $35 million wastewater treatment plant upgrade means that treated water released into the nearby Stillaguamish River is 15 times cleaner than before.

Jim Kelly, Arlington public works director, said the plant needed to be upgraded to protect the river, and because it was nearing capacity and exceeding the limits of its permit. He said the project also will accommodate expected growth in the Arlington area.

“We take our water out of the river so it's sort of like a big loop,” he said. “We put it back in the river 400 feet downstream and it's cleaner than when it's taken out.”

The Stillaguamish River feeds into Puget Sound, so improving it also protects the health of the sound.

Kennedy/Jenks Consultants was project designer and engineer. Imco General Construction of Ferndale was general contractor.

Photo by Katie Zemtseff [enlarge]

Todd Pike (left) and Jim Kelly at the Arlington wastewater treatment plant.

Planning began in 2005 and construction started in 2009. The new system uses an advanced system to remove biological nutrients, followed by membrane filtration.

Wastewater is screened to remove large particles like sand and grit. The advanced system removes nitrogen and phosphorous from the water before it is filtered by 21,000 membranes with pore openings 250 times smaller than a hair. Water is disinfected with ultraviolet light before going back into the river.

Before the upgrade, water went into one of two tanks. Once a tank was full, air would be blown in for 18 hours and the water would sit for six hours. Anything that didn't settle went back into the river.

Upgrades also allow the plant to reclaim water. Once it gets a reclaimed water permit from the State Department of Ecology, the plant will produce Class A water that will be used on a local cemetery. Potable water now being used on the cemetery will be available for drinking.

Reclaimed water will also go into a new wetland next to the plant. Arlington built the wetland as part of a separate project to treat stormwater before it enters the river. Sending reclaimed water to the wetland during summers will nourish plants in the dry season and give effluent a chance to cool and pick up oxygen from plants before entering the river.

“It's a win-win situation and it's the right thing to do, however Ecology is having a tough time putting their arms around it because it's so new and unique,” Kelly said.

The wetland was designed by Landau Associates and the city's engineering staff. It was built by Reese Trucking & Excavation of Darrington.

The upgraded plant is very efficient. The team spent $900,000 on energy upgrades, of which $450,000 came from a federal stimulus grant. Kelly said the upgrades will save $180,000 in energy costs each year, and that will pay for the investment in five years.

Efficient systems include fine-bubble diffusers that disperse oxygen into water, variable frequency drives that allow motors to run at adjustable speeds and smart motor controls that use Ethernet to share information.

The DJC previously reported the Arlington project was the first in Snohomish County to get part of its funding from federal stimulus money. Another $5 million came from state revolving funds under the stimulus. Kelly said the savings get passed onto ratepayers.

Kelly said Imco and Kennedy/Jenks worked through problems together. One thing that helped, he said, is Imco took team members out to lunch after each weekly construction meeting, and they talked about anything but work. “I don't think I've heard of a project where (such strong) synergy on site was developed,” Kelly said. “At the end of the project, it was sad to see them go.”

Todd Pike, project manager at Imco, said the relationship of the team members was like a marriage. “We had some tense times but at the end of the day you just went to the dinner table and worked through it.”

The city had trouble getting the project started because of permitting issues. Once Imco was chosen as the low bidder and the contract awarded, the city issued three notices to proceed. It took four months before the project was fully under way. Imco used the extra time to look at specified products quoted for the job and in several cases identified cheaper options. “Normally, you don't have that much time,” Pike said. “We were able to utilize that time and we were able to offer close to $400,000 worth of savings before we even put a shovel in the ground.”

To capitalize on the summer construction window and make up time, Pike said he requested the work week be increased from 40 to 50 hours, which was a key factor in getting the project done ahead of schedule.

The project had nine change orders with a total cost increase of $92,000, representing less than one percent of the project. Generally, Kelly said change orders cost between three and five percent, and this saved the city money.

Part of the reason the project was successful, Kelly said, is the city was flexible in items such as working more hours during the summer. “You wonder why projects go over 5 to 8 percent... it's because (owners) fail to work with their contractor. They try to steer the ship,” he said. “(They) basically shoot themselves in the foot.”

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