SALEM, Ore. -- Inside a shed on Geren Island in the middle of the Santiam River, an experiment is underway that could hold the solution to Salem’s water woes.
“Its just a small scale test of what we're going to be doing full scale," said engineer Katie Ottoboni, who is overseeing the tests.
Small amounts of activated powdered carbon are mixed with river water before any treatment on the island.
It looks like tiny bits of black sand, and is so small some seemed to be absorbed by the fibers of notebook paper.
While the particles are tiny to our eyes, they're big in the microscopic world, and sticky. The nasty cyanotoxins causing trouble for Salem have trouble getting past the carbon bits, which is good because nothing else has efficiently stopped them.
But after they load up on toxins, the carbon bits are supposed to sink to the bottom and so far in tests they are not.
“So, we turned it on we were not getting as good a settling as we thought,” said Ottoboni. “So that's why we're using the pilot to say—okay if we don't get great settling what does that look like full scale?"
It might look like the clogging of huge sand filters below settling ponds that stretch across two acres on the island.
“Exactly. Clogging of the filters. So that's what we're really testing,” Ottoboni said.
Now, she and others are tinkering to see if they can make the carbon bits sink better and stay away from the big filters.
Salem has 50,000 pounds of the activated powdered carbon, enough for about a week's worth of full scale use and more is on the way from around the country. In the meantime the Salem’s emergency manager says water testing is continuing.
“We're continuing to monitor at all the same sites and including starting to add locations such as Big Cliff -- so adding additional testing locations so we can really get a better feel of what the situation is in the reservoir and then all the way down through the system,” Greg Walsh said.
On June 10, the city announced that Salem's water advisory for children and vulnerable groups would last for at least two weeks as a precaution.