Qualchan to use filtered wastewater

An experiment to use class-A treated wastewater on Spokane city golf courses is moving this season to the Creek at Qualchan Golf Course.

The experiment began last year at Downriver Golf Course, where portions of the sixth and seventh holes were irrigated with treated and filtered wastewater.

The idea is to reduce the amount of water being taken from the region’s aquifer and to divert some of Spokane’s wastewater from going into the Spokane River where it is causing pollution problems.

Purple-coded irrigation pipe has been installed on the 15th hole green and the 16th hole tee area to spread the treated wastewater. In addition, the project includes a small shed for pumping and ultraviolet sterilization of the water.

Currently, Spokane’s wastewater plant is equipped for what’s known as a secondary level of treatment, in which bacteria and chemicals are used to nearly eliminate the organic solids and chemicals from wastewater prior to discharge into the river.

The state, under the federal Clean Water Act, is requiring the city to upgrade its sewer plant to filter out phosphorus and suspended particles as part of a $100 million program to protect the Spokane River water quality by 2014.

The city is purchasing six test units to study what type of filtration would work best. Water from one of those units is going to be trucked to the two golf courses to study how well the reused wastewater works on the grass.

Officials said they are unsure if dissolved salts in the water will cause problems for the grass. Downriver and Qualchan have different types of soils to help in studying the feasibility of reusing highly treated wastewater for irrigation.

The wastewater that is being applied to the courses is safe for human contact, but it is not clean enough for consumption.

Additional improvements, including reverse osmosis and advanced oxidation, could bring wastewater to a level of cleanliness that it would not harm the river, and could be used for irrigation above the region’s aquifer drinking water, said Dale Arnold, wastewater director for the city.

The advanced treatment, however, requires about twice as much electrical power, officials said. In addition, the plant would be left with salty brine that would have to be disposed.

The more that wastewater can be used for irrigation, the less of the region’s pristine aquifer water that has to be used and the less wastewater that goes back into the river, Arnold said.

Fairchild Air Force Base and city officials are developing a new water transmission system to serve the base. When that is finished, the base would no longer need its existing water line from pumps near the Spokane River to the air base. That line could be retrofitted to supply wastewater for irrigation west of Spokane.

Wastewater officials said there is increasing concern about traces of pharmaceutical drugs, cosmetics and personal care products turning up in the environment from wastewater. If cities are forced to remove those chemicals, the cost for treatment could increase beyond current spending by $170 million. The chemicals are showing up in water samples in the amounts that are in the trillionths.