Giant 'vacuum' to help clean river
Heidi Desch / Whitefish Pilot | Hagadone News Network | UPDATED 13 years, 4 months AGO
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.