Odor has been an issue at the North Bend wastewater treatment plant for years, but a new project approved by the North Bend City Council July 16 should cut the number of complaints.
The council awarded a contract for up to $72,000 to Gary Harper Construction, Inc. of Sno-homish for repairs and updates to a 10-year-old dryer, plus electrical and piping modifications needed to complete the repairs.
North Bend Public Works Director Frank Page explained that the odor control unit on the dryer, the component that filters the dryer’s exhaust, failed and needs replacing.
The dryer processes the solids, extracted by biological and centrifugal processes from the waste stream, to further break them down, Page said, and the exhaust system should filter out any remaining solids or liquids (steam) in this step.
When the new exhaust system is in place, he said, “the air and steam coming off the drying unit will go through a stainless steel odor unit, that uses water to knock the odors down. Then the air goes through a biofilter… and by doing that we believe we’re going to knock the odor down.”
The new odor unit, however, could take several months to fabricate, Page told the council, so “We’re looking at some options this summer to minimize the odors coming from the plant and the impact to the public.”
The plant doesn’t operate 24 hours a day, nor daily, so one option would be to run the dryer only in the mornings, when it’s cooler, Page said. The plant doesn’t run on weekends.
Page said the city gets frequent complaints about the odor from nearby residents.
“The people immediately to the east are the ones being impacted the most. And when it’s hot weather like this, it’s even worse,” he said.
Work on the dryer should begin by fall, but Page said people won’t notice any change until the project, expected to take about a month, is complete.
He also said the city has made several attempts to address the odor problems in the past, spending nearly $80,000 on projects in the past three years alone.
North Bend’s primary wastewater treatment plant was built some time in the mid 1950s, and an addition was built in 1978.
