Friday, March 07, 2014
Covering Dallas, Monmouth, Independence, Falls City and surrounding areas since 1868
Workers from R&G Excavating lower an aerator into a city of Monmouth sewage lagoon on Nov. 27. The device will draw air down through an impeller, promoting bacterial consumption of biosolids.
December 26, 2012
MONMOUTH -- An unfazed Danny Parker climbs into a rowboat, launches off the rocks and into the pond behind the Monmouth city shops.
Parker, who works for Scio-based R&G Excavating, ferries the boat in a calm and slow manner -- this isn't ordinary water, afterall.
"We're used to this," Parker said.
He and other R&G crew members were involved in the finishing touches of an improvement project on the city of Monmouth's 45-acre sewage lagoon system earlier this month.
Contractors installed aerator devices that float on the ponds, expediting the decomposition of ... well, you know.
"It's all we do, work in poop," Parker said. "It's when you have to put the waders on that things are really serious."
Monmouth's aging sewer system has been the subject of a $4.7 million overhaul during the last two years. Expanding the utility's lifespan and putting off building a full treatment plant until 2025 or 2030 has been the goal, said Russ Cooper, public works director.
"It's not glorious work," Cooper said. "But if we don't do it, you would have a whole different environmental impact story to write."
The city's lagoon system was built in the 1960s and stores about 21.4 million cubic feet of raw sewage. That wastewater must be stored and treated for seven months before it can be safely discharged -- under state standards -- into the Willamette River via Ash Creek.
But its construction came at a time when the city's population was less than a third of what it is today. There have been instances in the last 15 years where the lagoons have come close to exceeding storage capacity, Cooper said.
In the early 1990s, the city built an effluent reuse site that sends treated wastewater to a nearby poplar tree farm for irrigation.
"You don't see lagoons built anymore," Cooper said. "It's a real basic treatment, but they're low cost to operate."
The city dredged the three lagoons in 2011 to make more room and revamped the intake headworks to screen out inorganic material.
R&G deployed 32 aerators on two of the ponds in recent weeks. The device has an impeller -- a rotor in a tube -- that spins, draws in air and pulls it down into the wastewater.
This promotes aerobic bacteria growth and helps break down biosolids, Cooper said.
This fix will spare the city from having to immediately invest in a mechanical wastewater treatment plant, which would cost between $30 million to $40 million, said City Manager Scott McClure.
Using a boat to maintain the lagoons has been a periodic necessity, Cooper said.
Trust him, it's no place you want to be.
"I have seen a whole bunch of ducks sitting around the effluent pipe," he said. "That kind of put a halt to my duck hunting days."