New plant appears to cut phosphorous discharges

It’s hard to imagine, standing in the midst of hundreds of thousands of gallons of raw sewage, that things are looking better for the Spokane River.

But that’s what officials say is happening at Liberty Lake’s new Wastewater Treatment Facility. Though it’s too early to know for sure, numbers are showing a decrease in phosphorous discharged into the Spokane River.

“You couldn’t have hoped for better numbers,” said Dan Grogg, chief operator of the treatment facility. “It’s going to be much cleaner than what it was.”

The Liberty Lake Sewer and Water District spent $11 million building a new treatment facility and upgrading the old one. The new portion came online in January, and the remaining upgrade will take a few more months.

When it’s finished, the facility will have the capacity to discharge 2 million gallons of effluent each day into the Spokane River, though it will be a long time until the facility ever needs to discharge that much, said F. Lee Mellish, manager of the sewer district.

Currently the plant discharges about 725,000 gallons a day, he said. Much of Liberty Lake is still being developed, so the plant will be ready to handle any new construction within the boundaries of the sewer and water district.

The old plant, built in 1980, was reaching its capacity, Mellish said.

The new plant is state-of-the-art, employing a biological approach to treatment rather than a chemical solution.

Sewage reaches the plant in large pipes, where debris is removed with a giant auger.

It then enters several gigantic tanks, where bacteria and other biological processes break down the sewage.

The water passes through one portion of the plant where it is exposed to intense ultraviolet light, killing harmful bacteria.

Clean water enters the Spokane River, and leftover sludge is sent out on a complex conveyer belt system to trucks, where it can be spread on agricultural fields for fertilizer.

“We’re pretty happy with it,” Mellish said.

New computer technology allows workers to operate the plant remotely, even from their homes. If something goes wrong, the computer notifies the person on call.

New controllers work at a variable rate, saving thousands of dollars in electricity costs.

The plant’s eventual goal is to reduce phosphorous discharge rates into the Spokane River.

A 1985 court order involving water quality in Long Lake forced dischargers on the Spokane River to reduce their phosphorous levels. Liberty Lake’s sewer and water district was a forerunner encouraging a ban on laundry detergent with phosphates, and the district currently is encouraging people to use phosphate-free dishwasher soap.

The state Department of Ecology is in the process of setting new discharge standards, and the plant will have to wait until that study is complete and new permits are issued before it can operate at the full 2 million gallons-per-day discharge capacity.

The sewer district is also looking at using some reclaimed water to water golf courses in the city, reducing the phosphate load on the river.