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The Chisago Lakes Joint Sewage Treatment Commission discussed the chloride limits contained in its treatment plant permit last week in light of data that exceeded the allowed amount— before fines began to be imposed.

Chisago Lakes Joint Sewage Treatment Commission is mandated by its most recent permit conditions,  to address quantities of salt/chloride in treated wastewater now discharging into a creek.  There is no hard and fast limit on the chloride at this time but a January interim exceedance has some commission members concerned.

Sources of chloride range from street runoff (deicer salt) to home water softeners. Certain industrial uses and even breweries also contribute to demand for more pure water,  calling for use of chloride. 

The small Chisago Lake Township creek accepting the Chisago Lakes sewer plant’s treated outflow,  meanders to the Sunrise River and then eventually, to the St Croix River with opportunities along the way for seeping into area lakes.  Chloride is a big red flag to those protecting Minnesota’s environment due to its negative effects on water habitat and aquatic creatures.  The State began monitoring for chloride as early as 2009.

The sewer commission was recently granted a 15-year permit extension for the multi-city sewer plant.  However, state pollution control regulators also added an “interim” variance for chloride of 283 mg/ per liter,  measured in plant discharge averaged over a one month span. 

The national aquatic standard set as “toxic”  by the EPA  is a one day measurement of 860 mg per liter or a four day average of 230 mg/l.  The CLJSTC content in 2025 had an average of 263 mg/l.

Zach Meyers, plant operator for Veolia, took questions about chloride from the sewer commission members last week. Veolia was hired to run the sewer collection and treatment system. 

For starters wintertime is historically high-for chloride statistics due to de-icer.  Meyers added, the Minnesota PCA understands that this plant was not built to treat chloride.  It treats bio-solids and can degrade organic waste but chloride elimination is a whole different science.  

To avoid building a new plant or incorporating a costly reverse osmosis system, or potentially outlawing water softeners, the commission looks to public cooperation.

The pollution control agency wants to see a plan addressing sources of chloride in the wastewater collection area.

 Regulators are promoting minimizing the amount of chloride entering the system and owners of water softening systems can be part of the solution.   Property owners should be restricting which spigots are connected to your softener. You don’t need conditioned water for your garden, for example.  

Opt for an on demand unit versus a softener on fixed rinses. Research shows that fixed cycling  consumes more salt. 

Talk with an expert and choose the most efficient softener.

In the great outdoors use tiny amounts of de-icer on walks and driveways.  Keep salt storage protected.  There is known infiltration into the sanitary sewer through manhole covers, etc.

Local government units are reminded to support your employees interested in attending smart salt training.  Street maintenance  practices are important to reduce infiltration of contaminants.

According to the Pollution Control Agency’s educational materials some cities  have already done extreme projects like a centralized lime softening (non chloride) system, or have banned personal softeners altogether. Some locales have put together large sums of money to compensate private citizens for surrendering softener units. 

The CLJSTC  directed staff last week to keep monitoring the data.

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