Urban irrigation using wastewater or “reclaimed water” has been practiced for decades across the nation.
Now the City of Spokane has jumped on the water wagon with a reclaimed water-use pilot study, meaning there’s an extreme possibility in the near future, whenever a Spokane resident flushes their toilet, they’ll be ultimately contributing to watering the local golf course or feeding the fountains in the downtown area.
Of course, the “ick factor” will be attended to along the way before the stream of water reaches its final destination. Rather than a straight shot from your pipes to the sprinklers at Downriver, wastewater from the majority of residents and businesses who are on City of Spokane sewer, as well as water collected in storm water drains throughout the city, will first travel to the Riverside Park Water Reclamation Facility where the water is treated.
“The water we’re using for our pilot is especially clean,” says Lars Hendron, principle engineer in the City of Spokane’s Wastewater department. “The wastewater is purified to a grade A quality, meaning it’s safe for all human contact, except for drinking.”
This treatment is a highly engineered series of three treatment processes designed to speed up nature’s restoration of water quality, providing a high-level of disinfection to assure the water meets stringent requirements before leaving the treatment facility.
Started in the fall of 2007, the Reclaimed Water-use Pilot Project provides just 1 percent (about 5,000 gallons per course) of the daily water needed for each of two municipal golf courses in Spokane—The Creek at Qualchan and Downriver. The water is transported via water trucks to the sites where it is stored in tanks in which the water goes through the 3rd level of treatment—disinfection by ultra-violet rays. Although the portion of treated wastewater is small, it’s enough to study the feasibility of the project long-term. Throughout this process, the soil and water have been continually tested to assure the water is safe and the soil healthy.
“The soil samples have been consistently of high quality,” says Mike Greene, assistant superintendent of the Spokane Parks Department. “Although still in the evaluation stages, everything is coming back good so far.”
The testing, as well as design and general supervision of the project is contracted with AECOM, a global leader in providing fully-integrated professional, technical, and management support services for a broad range of markets.
The pilot is funded by existing residential and business sewer rates and is expected to continue over the next year or two, until enough testing has been done to assure not only the public of its feasibility, but the golf course managers as well. Hendron says they chose golf courses as the testing sites for the pilot due to the “more controlled environment in terms of public access” and because of the extreme care that is taken to ensure the turf is healthy.
“Also, golfers can be great P.R. for this type of project as they’ve been to courses where it’s been in place for awhile and they see how well it works.”
In fact California was the first on the map to recycle the precious resource and has been doing so for over 50 years. Oregon has been reusing their wastewater for the past 20 years. Across the nation, there are over 1,200 water reuse utilities in the United States, delivering billions of gallons of treated wastewater to customers who use it for irrigation and a variety of other purposes every day. Currently in Washington alone, there are 22 water reuse facilities, with 30 more slated for construction.
So why has it taken Spokane so long to make the translation from “wastewater” to “recycled water?”
“Our aquifer,” says Hendron. “We have an abundant water source; although it will serve to conserve what we have, that’s not our primary concern here; it’s rather driven by protecting our river from dangerous phosphorous levels.”
In addition to conserving our aquifer and preserving our rivers and lakes, the use of reclaimed water can also reduce the amount of fertilizers used due to its natural makeup of nitrogen phosphorous, and oxygen. Furthermore, withdrawals from surface water can be offset, bolstering water flows for fish, other wildlife and plants.
Other perks include reliability, as even in times of drought when restrictions are placed on the use of potable (drinking) water for non-essential uses like agricultural irrigation, recycled water is readily available. It’s also competitively priced sometimes costing 80 to 90 percent of the potable water rate for irrigation.
Plans for full-scale expansion of the reclaimed water use, although unsure, are estimated to be in place within the next three years, says Hendron. Currently the RPWRF Laboratory treats up to 44 Million Gallons per Day from a collection system serving City of Spokane and Spokane County.
For the project to go full-scale it would require the city to install piping which would carry the treated wastewater to the sites, working well for such discussed properties as Downriver Golf Course and Joe Albi Stadium, due to their proximity.
Other municipal areas discussed include golf courses such as Esmerelda and Indian Canyon, and cemeteries. In these cases, it’s most likely that small on-site water treatment plants would be constructed to directly receive amounts of local wastewater, alleviating the need for transportation and the costs associated with it.
Other uses can include:
Fire protection (purple fire hydrants)
Cooling or makeup water for a variety of industrial processes
Natural system restoration
“Part of the reason for the pilot was to garner public acceptance,” says Hendron. “What we’ve received has been really positive; the mayor and the city are really behind what we’re doing—the water conservation benefit is on everyone’s minds right now.”
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