The city of Coeur d'Alene is embarking on a nine-year plan to upgrade its wastewater treatment facility, at a cost of about $72 million, to comply with anticipated stringent new water-quality standards.

The city recently approved amendments to its wastewater utility department's 20-year facilities plan to account for what it expects will be necessary upgrades to meet the terms of a proposed federal discharge permit.

"We are about to build the most advanced treatment plant in the U.S., and maybe even the world," says Sid Fredrickson, the district's superintendent.

Coeur d'Alene recently awarded a $1.2 million contract to Shannon Industrial Contractors Inc., of Coeur d'Alene, to build a structure to house three pilot phosphorus-removal systems that the department plans to test over a two-year period. Those three systems cost a combined $1.6 million, and at the end of the pilot program, one will be selected for full-scale implementation, at an estimated cost of $50 million, Fredrickson says. In addition, the department plans to upgrade other components of its current treatment system and continue using them, to increase the plant's overall capacity to 12 million gallons a day, up from current capacity of about 6 million gallons a day. Adding in the overall cost of those upgrades, the system improvements will be $72 million. HDR Engineers Inc., of Boise, is designing the project, Fredrickson says.

The draft of a new wastewater discharge permit has been withdrawn for now, as the U.S. Environmental Protection Agency, which issues Idaho's permits, and the Washington state Department of Ecology, which issues Washington's wastewater discharge permits, conduct more research to determine standards for dissolved oxygen levels that will protect the Spokane River best. Phosphorus plays a big role in the dissolved oxygen levels which affect the health of marine life, Fredrickson says.

In the meantime, the city of Coeur d'Alene is studying which technology will help it meet the new requirements, which he expects to be at least as strict as those outlined in the draft permit, Fredrickson says.

The city's current wastewater discharge permit requires it to remove 85 percent of the phosphorus in its treated effluent, or to reduce phosphorus to no more than 1,000 micrograms per liter, whichever amount is lower, says Dave Shults, the department's capital program manager. That is an attainable goal for the facility using alum as a chemical coagulant, Shults says. The city doesn't, however, have the technology currently that would allow it to meet proposed standards of as little at 50 micrograms of phosphorus per liter, he says, adding that in some other communities in Idaho, regulators have proposed limits as low as 10 micrograms per liter.

"The agencies and their scientists have been trying to come up with a load of phosphorus allocation that will be protective to beneficial uses of water in Spokane River through its entire stretch," Shults says. "It would have us trying to remove phosphorus more than what current technology would allow."

Fredrickson says the upgrades will take the department down a completely different path.

"The good news is we will be producing treated effluent of such high clarity, we will have the ability to reuse the treated effluent," for irrigation, such as at cemeteries and parks, Fredrickson says. "We'll no longer be a wastewater treatment facility; we'll be a water reclamation facility."

Once a final permit is issued, which could be as soon as January, the department will have seven years to complete its upgrades, if the timeline stays the same as in the draft permit, Fredrickson says. Then, it will have two additional years to optimize the performance of its new equipment before it must comply completely with the permit requirements, Fredrickson says. The city will have to seek funding for the huge project, but it does currently qualifies for an $8.2 million loan with an interest rate of 0.5 percent, under the federal stimulus package, he says.

"We'll be asking the community to fund many improvements," Shults says.

Currently, Shannon Industrial is preparing to construct a building to house small-scale versions of the three prospective phosphorus-removal systems, at the city's treatment plant at 1080 W. Hubbard, in Coeur d'Alene, Shults says.

The three pilot systems include equipment called continuous upflow media filtration, from Blue Water Technologies Inc., of Hayden; a tertiary membrane filtration system from General Electric Co. affiliate Zenon Environmental Corp., of Trevose, Pa.; and a membrane bioreactor system, also made by Zenon. Overall, the city is investing $3.8 million in the pilot project, Shults says.

In the current construction project, Shannon will erect a 40-foot by 60-foot pre-engineered steel building that the city has purchased from Steel Structures America Inc., of Post Falls, and related infrastructure for the building. The company has begun site work, and the city hopes to have the pilot equipment up and running by December, Shults says.

An added benefit of the pilot project is that once the city selects the system it will use, its operators will have been trained in that more complex system through the pilot project, Shults says.

"We'll grow our own operators," Fredrickson says.