Sean C. Morgan
Of The New Era
When the weather started warming up last year, Sweet Home didn’t smell so good, but with this year’s summer heat over with, the city appears to have successfully gotten a lid on the obnoxious odors from its Wastewater Treatment Plant once and for all.
“I believe that we have solved the problem,” Public Works Director Mike Adams said.
In late August or early September, the Oregon Department of Environmental Quality received on report of an odor problem, but the cause wasn’t related to the chronic problem the city has dealt with for more than a year, he said.
The last time Adams heard about any complaints related to the ongoing problem in one of the treatment plant basins was around mid-July, he said.
The problem originated in what was called the “digester.” In September 2006, the city changed the equipment in that basin from a mechanical mixer to an aeration system. Within months, foul odors were becoming a problem as the equipment changed the way odors escaped the basin.
When the weather warmed up in 2007, the odor and the complaints became more frequent. The city took several steps to reduce the odor, including using a tarp to temporarily cover the basin.
The city installed a filter and a pump to push the air through the filter. It took a couple of weeks for the filter to begin working. It seemed to work for a short time, then “short-circuited” and stopped working properly, and the odor problem was soon persistent again.
In the spring, the city installed an aluminum dome over the basin so that the only way the air can get out is through the filter. Even after the dome was installed, odor problems continued.
“We added filter media (hog fuel), and we increased the size of the filter itself,” Adams said. “The original filter turned out not quite big enough.”
After enlarging the filter, the odor problem continued for several weeks, but it has apparently waned in the past couple of months.
“It took a while to understand what was causing what,” Adams said. “Unfortunately, it took a little time, but we think we finally got it. It certainly wasn’t resolved as quickly as we’d like, but it was not for lack of trying.”
The final bill to solve the problem was easily more than $200,000, Adams said. The aluminum cover was a large part of that cost by itself.
H said he is confident this particular issue is resolved, though he’s not making guarantees.
“I won’t say it won’t ever smell again,” he said, “because it is a sewer plant.”