Globs of foam on Rogue puzzle officials
Public works crews are on a hunt through the Rogue Valley's sewer system in search of the source of a chemical that has caused drifts of foam on the Rogue River periodically over the past six weeks.
Employees at Medford's wastewater treatment plant and anglers on the river first noticed the frothing on Oct. 12 inside the plant and at the pipe where it dumps treated water into the river just downstream from Touvelle State Park, state and local officials said.
"I was headed downriver to fish and saw this ridge of foam — 8 to 10 feet high — breaking up like an iceberg," said Bob Furry, a 63-year-old Eagle Point resident who spends several days a week on the river.
Workers at the treatment plant quickly tested the substance and discovered it was a surfactant, Medford Public Works Director Cory Crebbin said.
Surfactants change the surface tension of liquids and are used in cleaning, degreasing, firefighting and a multitude of other tasks in numerous industries, including agriculture and food preparation. Chemicals from that class of materials can be found in soaps, shampoos and detergents, pesticides, fertilizers and other common items, said Mark Hamlin, Salem-based manager of the Department of Environmental Quality's water quality section. They are generally biodegradable and don't accumulate in the bodies of those exposed to them.
"It doesn't seem to be toxic," Hamlin said.
While surfactants are a common ingredient in detergents, this substance isn't necessarily a detergent and apparently isn't adding phosphorous — a potentially problem-causing nutrient — to the water, he said.
The massive amounts of foam, however, did affect the plant's treatment processes and caused the city to exceed the limits on suspended solids it can discharge into the river, Crebbin said.
During October, the plant emitted an average of 10.9 milligrams per liter of suspended solids, slightly above the 10 milligrams allowed in its operating permit, Crebbin said. The permitted amounts change seasonally and, as of Nov. 1, the limit increased to 30 milligrams per liter.
"We are well below our permit limits now, but not as far below as we usually are," he said.
He explained that the plant coagulates solids so they settle out of the wastewater and can be broken down by bacteria. The foam interfered with the clumping and settling, but didn't harm the bacteria, he said.
The city got a defoaming agent from the Medford Water Commission, which uses it in treating drinking water, to help control the foam when it was at its worst last month, Crebbin said. Officials are working with water quality experts to determine how to safely add the defoamer as necessary.
Crews also are working to find out where the foaming substance is coming from.
First, they checked with major industrial users — mills and food processors — that are required to keep lists of chemicals present at their plants, Crebbin said. None of those sewer customers reported spills or changes in chemicals or processes that would have added surfactants to the system.
Now, crews are heading out to begin testing the sewage at 4,000 access points in the valley-wide sewer system to try to determine the chemical's origins, Crebbin said.
"We want them to track it down and get to the bottom of it," said Dan Van Dyke, a district fish biologist with the Oregon Department of Fish and Wildlife. "It's not something anyone wants in the river."
His department has asked anglers and treatment plant workers to watch for distressed or dead fish.
"We haven't seen any direct impact on fish and wildlife resources on the river," he said.
Furry reported two dead fish — possibly trout about 6 to 8 inches long — in the area and said fish don't seem to be biting in the stretch of river where the foam has appeared and the water sometimes looks white and murky.
"Maybe I'm looking for a reason I can't catch fish," he said with a chuckle, but added, seriously, that he was concerned about what the substance might do to fish.
Wimer-based guide Dave Carney, who operates Carney's Fishing Adventures, has been in contact with fish and wildlife and wastewater treatment officials. He said he hadn't seen any fish kills or other problems and felt officials were working to get to the bottom of the problem. Still, he hopes to see an improvement soon.
"It's bad bringing clients from out of town down our beautiful river and seeing these big clumps of foam," Carney said.
He described blobs 10 feet wide and up to 4 feet tall breaking free from a large ridge of foam at the sewer plant's outfall pipe and floating along the river at the height of the problem last month.
"It looked like Antarctica with big blocks of white drifting by," he said.
Reach reporter Anita Burke at 776-4485, or e-mail firstname.lastname@example.org.