Ecology says no to basin aeration
OXYGEN: Air process could help clean wastewater
in Chehalis River, but state says it's not good enough alone
ROCHESTER - Chehalis Basin Partnership members heard Friday from the Department of Ecology about the agency's position on aeration as a method of increasing dissolved oxygen in the Chehalis Reach.
Chehalis city officials, now examining a number of alternatives for meeting state wastewater discharge permit conditions, invited Gary Wegner, designer of the "CirCulation Machine," to join the discussion.
Chehalis wants Ecology officials to approve a pilot aeration project.
"We will not allow aeration in the river in place of treatment," said Kahle Jennings, Ecology's regional water quality specialist.
But he acknowledged Chehalis is looking at "enhancing treatment and then aerating" if its wastewater discharge still does not meet state water quality standards.
Jennings agreed increasing dissolved oxygen would be a side benefit of aeration, but he said the river's ecosystem is adapted to the natural conditions of the river.
An artificial system increasing the oxygen level can create an artificial ecosystem, he said.
"If the artificial aeration system collapses, the other system collapses also," Jennings explained.
But Wegner, a former Centralia College farm management instructor, said he has designed "a machine that provides circulation. It's not a conventional aerator." "We have to get down to the basic biology, which is replacing the missing link in the river," Wegner said. "That missing link is circulation." Wegner says his machine can reduce odor in a dairy lagoon by 90 percent within six months.
Dissolved oxygen levels in the slow-moving Centralia Reach is naturally below state water-quality Standards. Under Ecology rules, the river's natural condition becomes the standard which must be maintained.
During low-flow periods - usually between May and October - the river becomes even more stagnant. Warmer water also has less capacity to absorb oxygen.
"The lack of circulation deprives the aquatic environment of oxygen that is needed by the environment to promote the natural cleansing processes that we normally expect in a stream or river," Wegner's promotional brochure explains. "We can duplicate what happens naturally in a stream or river," it promises.
Wegner says his three-quarter horse power machine pulls colder water from the bottom of a body of water, drawing it to the top where it can absorb oxygen.
But Jennings is firm in his position. He says state and federal regulations do not allow Ecology to permit aeration of the river.
Chehalis Public Works Director Barry Heid said aeration is only one of the alternatives the city is investigating, but he believes aeration could improve water quality in the river - and save the city millions of dollars.