The public is invited to weigh in on an issue that affects them in the most intimate ways, including their laundry, their appliances and how their skin feels when they get out of the shower.
That issue is using salt to soften water — or to melt ice — and it’s creating big problems for the Alexandria area.
Homeowners pour salt into their water softeners, and after it does its job, the salty residue drains into the sewer system and ends up at the Alexandria Lake Area Sanitary District treatment plant on Lake Winona. The plant can remove a lot of things from the water but not salt. The salt, or chloride, then ends up in Lake Winona, where salt levels have skyrocketed to well above legal limits. Once salt ends up in water bodies, officials say, there’s really no good way to get it out.
“The solutions aren’t easy ones,” said Scott Gilbertson, the sanitary district’s executive director. “And they’re not solutions that anyone is going to be happy about.”
Getting rid of water softeners?
The sanitary district is facing the brunt of the problem, as it needs a permit to be able to discharge water into Lake Winona, and a permit would require it to significantly reduce the amount of salt it discharges into the lake. However, that would cost so much money — up to $107 million — that it would result in “substantial and widespread” social and economic consequences, said Elise Doucette, a policy specialist for the Minnesota Pollution Control Agency.
It’s much cheaper to reduce salt levels long before the water reaches the plant.
That’s where the public comes in. The Minnesota Pollution Control Agency is asking for public input to allow the sanitary district to discharge salt into the lake as long as it is working with other partners, including homeowners, to figure out a solution.
Solutions could include everything from getting rid of home-based water softeners to building expensive treatment systems.
To read and comment on the plan via mail or email, visit www.pca.state.mn.us/public-notices and scroll down to Tuesday, July 14, for the only public notice listed for Alexandria. Comments may be submitted through Monday, Sept. 14. A public hearing is scheduled online for Thursday, Sept. 3, from 5-7 p.m.
The sanitary district is seeking what is called a variance, which allows it to bypass legal limits for a certain time period.
“The intent of the variance is to give them the time they need to do the investigation,” Doucette said. “What is that something we’re going to do? It is not yet clear. It is going to have to be a community kind of decision.”
A complicated issue
Home use contributes about 73% of the salt arriving at the treatment plant, but residences aren’t the only culprits. Industrial use contributes 17%, according to a city of Alexandria study cited in a 2018 MPCA report, “Alternatives for addressing chloride in wastewater effluent.” Also, salt arrives in area lakes from other sources than the treatment plant, such winter road crews spreading salt on icy roads, and others sprinkling salt on sidewalks and parking lots.
Lake Winona has 400 milligrams of salt per liter when it should have no more than 250. Lakes Henry and Agnes, which are downstream of Winona, also have too much salt.
They’re approaching levels that can prevent macroinvertebrates such as mayflies from reproducing. People may shrug off mayflies as insignificant, but frogs, birds, fish and other critters feast on them.
“You care about mayflies if you want to fish, and it’s a food chain issue,” Doucette said.
Only one other Minnesota water treatment system has received a variance for chloride. In March, the system in the Stearns County city of Avon received a variance for 15 years, she said. If approved, ALASD would be the second, and several others around the state are also seeking variances.
“For Alexandria Lake Area Sanitary District, they have already looked at the issue,” Doucette said. “They are ahead of the game so we are only looking at a seven-year variance.”
Addressing salt pollution is made more complicated because of the situation in Alexandria. One possible solution would be for Alexandria Light & Power, which delivers drinking water to customers in the city limits, to install a lime softening plant, so that water would arrive at peoples’ homes already softened. Lime residue is much easier to dispose of than salt residue, and residents wouldn’t need to use home softeners.
However, 4,500 of the sanitary district’s customers are on private wells, so they would continue to need softeners.
The sanitary district also has another pollutant to worry about, and that’s phosphorus, which spurs the growth of algae. It has been taking steps to deal with that pollutant, including removing invasive carp, which stir up phosphorus, and using alum to bind to the phosphorus and sink it to the bottom of the lake.
The district may have to draw water out of Lake Winona, which would require approval of lakeshore owners. Phosphorus levels may also require some expensive fixes, including more equipment at the treatment plant.
While the treatment plant is operating well within its phosphorus limits now, Gilbertson said, that’s because it’s also not handling the volume of wastewater it is designed to handle. If growth pushed the district to capacity, it would run into problems.
“Our filters and our existing treatment system just would probably not perform to those levels,” he said.