Alexandria public meeting addresses chloride pollution in wastewater treatment discharges to local lake

Contact Dan Olson, 218-846-8108

Minnesota has a growing salty water problem that threatens its freshwater fish and other aquatic life. It takes only one teaspoon of salt to pollute five gallons of water. Once in the water, there is no easy way to remove it. Wastewater treatment facilities are a major contributor of chloride to lakes and rivers.

The Alexandria Lakes Area Sanitary District (ALASD) is working to address chloride (salt) levels in the wastewater it discharges to Lake Winona. The lake has 400 milligrams of salt per liter, which is above the water quality standard of 250. Lakes downstream of Winona also have elevated salt levels. Too much salt in the water can negatively impact aquatic insect communities that fish and other creatures depend on for food.

ALASD has explored the cost of building centralized systems for removing chloride in its discharge water. These included water softening technology using lime and reverse osmosis. These studies showed implementing any of the various centralized treatment options would result in significant cost increases to local residents above a certain threshold that made ALASD eligible to apply for a variance to water quality standards to give it more time to study the problem and develop solutions.

The Minnesota Pollution Control Agency (MPCA) will host an online public informational meeting on Thursday, September 3, on its proposal to reissue ALASD’s wastewater treatment permit with a variance that would allow the facility more time to find ways to reduce chloride in the water its discharges and eventually meet water quality standards. The MPCA is also accepting comments on the permit and variance through Monday, September 14.

Minnesota has some of the hardest water in the country, which prompts people to use water softeners. The City of Alexandria’s water supply is considered to be hard and many city residents, as well as area homeowners with private wells, use water softeners.

Water softeners need salt (which contains chloride) to recharge their softening capacity, and the resulting salty brine is discharged to municipal wastewater treatment plants in most cities. The plants are not designed to remove chloride from wastewater, so the chloride ends up in nearby bodies of water.

The first chloride variance in the state was issued in March to the city of Avon. If the ALASD variance is approved by the EPA, it will be second.

The public meeting will be held online via Webex on September 3 starting at 5 p.m. and ending after a presentation and questions — no later than 7 p.m.

See the MPCA’s water quality variance web page for a link to the meeting and additional information about the permit and variance. A link to the meeting is also available on the ALASD website.