Faced with the prospect that spending hundreds of millions of dollars to meet expected new environmental regulations still wont be enough, the city of Spokane is again studying the option of piping some of its treated waste water elsewhere, rather than discharging all of it into the Spokane River.


The city is using an $80,000 grant from the Washington state Department of Ecology to analyze the feasibility of diverting to agricultural lands at least some of the 34 million gallons of waste water its metropolitan plant in northwest Spokane currently discharges into the river during the summer each day.


Instead of studying the cost to dump the water, this study is looking for agricultural land where it could be used as a resource, and even a potential revenue stream to offset capital costs, says Jim MacInnis, a senior engineer with the city.


If the study determines the idea is feasible, the next step would be to draft an economic analysis of that alternative, which has been discussed extensively in the past, MacInnis says.


The city of Spokane and other entities that discharge waste water into the Spokane Riverthe city of Liberty Lake and private dischargers Inland Empire Paper Co., of Spokane, and Kaiser Aluminum & Chemical Corp.s Trentwood plant, in Spokane Valley; and the cities of Post Falls and Coeur dAlene and the Hayden Area Regional Sewer Board plant in Hayden, in North Idahoface stringent new regulations, primarily in regard to phosphorus.


Jim Correll, area manager for Denver-based CH2M Hill Inc.s Spokane office, which designs waste-water plants, says Ecology could well institute a 10-microgram-per-liter standard for phosphorus levels in the Spokane River. That compares with levels of 20 to 30 micrograms currently recorded upstream from Inland Empire Paper and the Spokane treatment plant, and the 400 to 500 micrograms-per-liter discharges currently allowed for plants that discharge into the river, Correll says.


The technology does not yet exist to do anything like what we expect the DOE (Ecology) to require in full scale, says Correll. He says the anticipated 10-microgram-per-liter phosphorus standard can be achieved in laboratories on a small scale, but cant be sustained.


You can get below 10 micrograms per liter, but you cant stay there 24 hours a day, seven days a week, Correll says. And the process would be horrifically expensive. There would be a large amount of solids that would have to be disposed of, and it would be very expensive to pump all the chemicals into the waste water to start the process.


The city already has plans to spend $400 million over the next 12 years to remove phosphorus from the waste water and deal with storm overflows, meet those requirements, but some officials are worried that even those capital projects wont provide a system thats capable of meeting the expected new phosphorus standards.


Correll disagrees. I think the $400 million will suffice, he says.


A 2-year-old study done by CH2M Hill estimated that it would cost more than $500 million to put in pumps, pipes, a facility, and to hire staff to implement a plan to pump treated waste water up to 10 miles west of the treatment plant to be used for irrigation in Lincoln County, says Correll.


Lars Hendron, a city waste-water engineer, says, If we were to go to full-land application in addition to money already committed to help clean up the Spokane River, the cost to the city could easily approach $1 billion over the next 15 to 20 years.


Land application could include the underground installation of 6-foot-diameter pipes whose flows could be powered by three, 2,000 horse-power pumps, with a fourth such pump kept as a backup, Hendron says.


He says the treated water currently being released into the river by the waste-water treatment plant is safe for agricultural uses, but isnt filtered and thus cant be used for Class A purposes, such as watering a golf course, where such water would come in contact with humans.


The plant has been discharging its treated waste water into the river since it was built in 1958, but discharge-quality standards have been getting increasingly more stringent.


The standards set limits on the total maximum daily load, or TMDL, of specific pollutants that are allowed to be discharged into the river and other bodies of water. There are different TMDL standards for different uses of the water depending on whether the water is discharged into a stream thats used for drinking water, recreation, aquatic life, or other uses.


Common pollutants the DOE is trying to control in the Spokane River include phosphorus, ammonia, metals, and polychlorinated biphenyls, Hendron says. Another area of concern is depletion of oxygen in the water when excess phosphorus stimulates major algae growth, which, when the algae dies, causes bacteria to deplete oxygen levels while breaking down the dead algae, says Correll. He says temperature controls, aimed at keeping the Spokane River cool, will soon be a matter for regulation as well.


Diverting some of the treated waste water from the plant to agricultural lands could help the city meet expected new TMDL standards, but that alternative, too, has its drawbacks, because that would reduce the amount of flow in the Spokane River downstream from the plant.


We are very interested in cleaning up the effluent and continuing to discharge into the river. Keeping water flows up in the river is very important, Hendron says.


MacInnis says about half of the $400 million already earmarked by the city for waste-water improvements over the next 12 years would be spent for upgrades to the treatment plant, including about $105 million specifically set aside from 2010 to 2012 for phosphorus-removal improvements.


The remaining $200 million would be spent from 2012 to 2017 to build dozens of holding tanks around the city to store storm water during high-precipitation weather events until that water can be treated at the plant. Currently, millions of gallons of combined storm water and untreated sewage are dumped directly into the river annually during those events, because the storm water, along with regular sewage flows, are too much for the plant to handle at those times. That, says MacInnis, is a factor in trying to meet TMDL counts, though Correll says it isnt a big factor because storm-water events normally come in the months other than April through October when low river flows make TMDL more of a problem.


Only last month, Washington became the first state in the nation to pass a statewide ban on the use of residential dishwashing detergents with phosphates. That law will go into effect July 1, 2008, for Spokane, Whatcom, and Clark counties, which have current water-quality problems, and in 2010 for the rest of the state, Rawls says.


The Spokane treatment plant currently uses the same phosphorus-treatment process as the city of Coeur dAlene, where a chemical that bonds to phosphorus molecules is added to the citys waste water. Made heavier by that process, the bonded product sinks to the bottom of tanks where its sucked out by a hose and ultimately piped to digesters, says Mike Coster, operations superintendent at Spokanes waste-water plant. The process removes from 90 percent to 95 percent of the phosphorus from the waste water, says Coster.


The plan for now is to install membranes or fine-sand filters that will remove even more of the phosphorus, says MacInnis, a former waste-water plant inspector for the Idaho Department of Environmental Quality.


By the time we start the design for phosphorus-removal units in two years, the technology will all be advanced, MacInnis says.


The countys role


The city of Spokanes plant currently sets aside 10 million gallons of its 44-million gallon daily capacity to treat waste water for Spokane County, under a contract through which the county pays the city about $10,500 a day, or about $3.8 million a year, says Bruce Rawls, utilities director for the county. The county also pays an additional $1 million to $3 million each year for its share of capital improvements to the waste-water treatment system, Rawls says.


The city contracts as well with the city of Airway Heights and Fairchild Air Force Base to treat their waste water.


Spokane County, which in turn provides waste-water treatment for the cities of Spokane Valley and Millwood, as well as some other areas in the county not served by the Spokane and Liberty Lake treatment plants, now plans to construct its own treatment plant, says Rawls. Its expected to cost more than $100 million and could come on line as early as 2011, he says. The plant would have a capacity of 8 million gallons a day, and the county would continue to send flows to the city of Spokanes plant under the 10-million-gallon-a-day contract.


The county bought a 20-acre former stockyard site near Freya Street and Trent Avenue in East Spokane for the proposed plant, but has been awaiting a permit from Ecology to build it, because that plant, too, would have to meet stringent requirements to discharge treated waste water into the Spokane River.


Diana Wilhite, mayor of the city of Spokane Valley, which has been working on the new plants plans with the county, says an agreement is imminent between Ecology and the county that would allow construction to go ahead.


I think an agreement to get a permit will be reached within the next month, or at least within the next two months, says Wilhite.


Thats consistent with Corrells assertion that the DOE and dischargers into the river will reach an agreement in the next couple months regarding what can be released into the Spokane River


Rawls says the new plant is needed to meet future growth. The county, he says, currently sends an average of 7.7 million gallons of waste water to the Spokane plant daily, and expects to reach a daily average of 10 million gallons by 2012. Growth is coming both from population increases and the countys plan to provide sewer service to an estimated 10,000 homes in the county that still use septic tanks, another big cause of TMDL excesses.


With all the sewage-treatment system upgrades being planned by various jurisdictions in the region, one long-range possibility that could benefit all those jurisdictions and improve protection of the river and aquifer would be to form a single, regional waste-water agency, Rawls says.


Such an agency would be more efficient, save money, and provide for a more holistic approach to meeting water needs in the area, he says. If population continues to grow like it is now, and as its planned to grow for the next 20 years, we could have a serious problem in recharging the aquifers.


Contact Rocky Wilson at (509) 344-1264 or via e-mail at rockyw@spokanejournal.com.