A few years ago, a Tulalip Tribes delegation traveled to England to tour a high-tech wastewater plant that used newly developed Japanese technology to process sewage. It was highly effective, produced no bad aromas, cost less to operate than conventional facilities and didn’t need acres of settling ponds and aerators.

Impressed by the new technology, the tribes began planning their own facility, adapting the revolutionary membrane technology developed by Kubota Corp. In 2003, the Tulalips’ own membrane plant was online. Today, it’s still operating as efficiently as predicted, so well that it’s even drawing its own tours of visitors from other states, Australia and Japan.

Now, the tribes are about to begin a series of new environmental projects with the plant, an effort that is attracting the attention of University of Washington scientists.

“We’re looking at forest irrigation, wetlands development and even a new biosolids fertilizer project that would produce a product from the plant,” said Lukas Reyes, utility superintendent for Quil Ceda Village Utilities &Environmental Services department. “There’s no real odor from the plant, except for smelling like clean dirt.”

Environmental scientists from the University of Washington are studying the test irrigation areas near the facility to evaluate the impact of the facility’s cleaned wastewater on plant growth and related issues. Studies of the wetland areas also will determine if the water is beneficial for enhancing salmon spawning.

“Once the pilot programs are finished, we’ll expand to a larger site on the old Boeing test facility property. Also, one of the major uses of the plant’s clean water will be for landscaping irrigation, including the landscaping around the casino,” Reyes said.

Meanwhile, the facility continues to do what it was designed to do, processing all of the wastewater received from Quil Ceda Village’s casino, retail centers and offices. In 2008, the plant also will treat all of the wastewater from the new 12-story, $130 million Tulalip Casino Resort Hotel when it opens.

The plant was the second of its kind to open in the Pacific Northwest, soon after a smaller one in Oregon that’s used primarily for golf course irrigation. But the Tulalip plant remains one of the largest membrane technology plants in the Americas and still has capacity to expand as Quil Ceda Village grows.

“The Japanese system uses large membranes to trap air in the system, allowing a higher concentration of ‘bugs’ to breakdown waste products,” he said, describing it as an odorless system that produces less sludge and purer water in a much smaller space than comparable systems that require large settling ponds. After screening out solids, the wastewater is aerated, filtered multiple times and disinfected with ultraviolet beams before being discharged into surrounding fields.

Like other treatment plants, microscopic organisms are used to treat the wastewater. However, the membrane bio-reactor (MBR) system’s 400 membrane plates filter the biological mixture, retaining the organisms as water flows through the membrane. As a result, three to five times as many organisms are used compared to traditional plants, allowing more treatment in a much smaller facility.

“We’ve been using those plates since the plant opened four years ago without having to replace any of them,” he said.

Using an MBR filtering system made the facility unusual from the start. But, even though the technology was Japanese, the Tulalip facility’s final engineering design was thoroughly Tulalip.

“All we did was buy the membrane boards from the Japanese. Then we worked with Parametrix Inc., a Sumner firm with a Bellevue office, on the design and with Harbor Pacific Contractors Inc. of Woodinville on the construction to build a plant that would suit our needs,” Reyes said.

Currently, the plant is processing about 250,000 gallons a day with one filtering tank. Using two of the four existing tanks would treat 800,000 gallons daily, and all four would process almost 2 million gallons a day. Provisions have been made to eventually extend the building, doubling its size, to boost the cleansing capacity to 4 million gallons per day, he said.

For the control room, Parametrix created a touch-screen, computerized system that tells Reyes at a glance exactly what’s happening in the plant, from the flow of the waste streams to levels of oxygen, nitrates and nitrites and how the pumps and mechanical system are functioning.

“You’ve got to know your biology to keep the system in balance. Once you do, then it’s a pretty simple operation that we can even monitor and adjust remotely, in case we’re off the site or even out of town,” Reyes said.

Overall, the performance of the plant, located a few hundred yards west of Quil Ceda Village, has more than satisfied the Tulalip Tribes’ goals, and it’s still attracting attention around the world.

“We have the biggest and longest operating MBR plant in the country, and we regularly get visitors for tours, including environmentalists and wastewater plant officials from many places, including Australia and Japan,” said Reyes, who has been on the site from the first day of the project. “Because we planned ahead to build it far beyond the immediate capacity we needed, we’re prepared for future growth at Quil Ceda Village.”