Giant 'vacuum' to help clean river

Clean-up on the next section of the

Whitefish River should begin in early August, according to the U.S.

Environmental Protection Agency.

Crews are expected to begin setting up

on the river between late July and early August with clean-up

expected to begin two weeks later. Work will likely continue until

Thanksgiving, said David Romero with the EPA.

This is the third phase of clean-up on

the river to remove contaminated sediments. Crews will work from

the Second Street bridge downstream to U.S. Highway 93 or Spokane

Avenue. A few smaller areas of contamination located beyond U.S. 93

to JP Road will also be cleaned.

This phase will use a wet dredging

system. This differs from the first two phases, which used dams to

contain the river before removing the contaminated sediment.

Romero said the wet dredging system was

chosen because of the section along the river. Private individuals

own much of the area along that section of the river.

“Access is an issue,” he said. “As you

move through town there are more private property owners. Noise was

also a factor.”

The wet dredging system will use a

large kind-of vacuum that will suck up the contaminated soil and

move it to a cleaning area.

“It pulls up all the dirty sediment

down to the native clay layer which is clean,” Romero said.

The soil and water will move through

piping creating a slurry. The mixture will be moved to holding

ponds where it will be kept aerated. Then the dirty sediment will

be extracted from the water and put into bags. The water collected

will be filtered, cleaned and tested before being put back into the

river.

Crews are expected to move along the

river until the end of November. Work should resume in March or

April 2012 where crews leave off this year. There’s about 5,000

feet of river to be cleaned.

“They could do it year round without

too many complications,” Romero said. “But working in the cold is

hazardous.”

High water on the river should have

little affect on the operation, Romero noted.

During the clean-up, the city

pedestrian-bike path and river access will be closed in the area

for safety reasons. The upstream cut off point will likely be at

the BNSF property and the down stream closure will be determined by

where crews are located.

The cleanup project was initiated after

EPA received a report in 2007 of an apparent sheen at several

locations on the Whitefish River. EPA investigated and discovered

petroleum products contaminating river sediments at several sites

along the river. Citing the Oil Pollution Act, EPA ordered BNSF to

clean up petroleum contamination from the Whitefish River and to

restore it to as close to pre-removal conditions as possible.

The Whitefish River clean-up is being

implemented in three phases. Phase 1, which lasted from September

2009 to January 2010, focused primarily on removal from a 500-foot

stretch of river below the BNSF roundhouse and refueling facility.

In Phase 2, contaminated sediment was removed from the river bottom

after the river’s upper reach was drained.