WILLMAR - While Willmar has several years to meet the Minnesota Pollution Control Agency's water standards regarding salty discharge, both the city of Willmar and Willmar Municipal Utilities are already looking for ways to reduce the amount of chlorides, sulfates, salinity and dissolved minerals that find their way into the city's wastewater, which can negatively impact water quality, vegetation and wildlife.
"This is a national limit set on all water," said John Harren, Willmar Municipal Utilities general manager.
The city and the Municipal Utilities will work together on this issue, as both have a role to play in providing Willmar safe water. The city is responsible for treating and discharging wastewater and the Municipal Utilities treats the drinking water supply before it reaches consumers.
"It is a partnership with the city to do this," Harren said.
The city of Willmar gets most of its drinking water from wells, said Joel Braegelman, Willmar Municipal Utilities water and heating supervisor. There are two water treatment plants in Willmar. Currently, 65 percent of the city's drinking water is treated through the southwest plant, with the remaining going through the northeast plant.
Once water enters the sewer system, it becomes the city's responsibility at the wastewater treatment plant on the west side of town near the airport.
The partners are looking at a few ways to address salty discharge limits, including planned upgrades at the northeast water treatment plant and educating the public about what can be done to reduce the amount of salt in the water.
The salty discharge is measured at the wastewater treatment plant. But, there is no affordable way to treat the salt content at that point.
"Because of the expense to treat the water on the wastewater end, there is no good way to remove salt," said Sean Christensen, Willmar Public Works director.
This means the most cost-effective treatments occur either before water comes to consumers or while it is in the homes and businesses - where most of the salt is added.
"For the most part, that comes from home softeners," said Braegelman, adding that the city's well water is usually harder than consumers would like, resulting in the use of salt-based softeners.
Other causes of high salty discharge include food processing and animal rendering industries, according to the MPCA.
New high-efficiency water softeners, while more expensive on the front end, use less salt, which means lower operating costs for users and better water quality for the city. The hope is more residents will upgrade to high-efficiency models when the time comes to replace their current systems.
"Education and outreach is going to be a big item," Christensen said.
Upgrading the northeast water treatment plant could also reduce the city's salty discharges. Willmar Municipal Utilities has been planning and designing upgrades at the facility since 2012 to better remove ammonia from the water. The initial preliminary design has an estimated cost of $4.2 million. While the Municipal Utilities Commission has not yet approved this project, these are updates that are needed at the plant and Harren hopes to start construction in 2019.
Completing these upgrades would allow the utilities to flip the amount of water treated at each plant, meaning 65 percent would come from the northeast plant, and 35 percent from the southwest plant. This could reduce the amount of salt in the water because the northeast plant has naturally softer water than the southwest plant.
"The community would soften less, which would reduce the salty discharge," Braegelman said.
The utilities also added projects to the preliminary design of the overall treatment plant project to assist in lowering the city's salt numbers. A sulfuric acid system was added, for example. Sulfuric acid lowers the pH of water, which can also lead to softer water.
"We added some possible chemicals to change some of the process," Braegelman said.
This and other additions to the plant project's preliminary design have raised the costs substantially - to $9.2 million. There is the possibility of grant dollars and loans to help fund the added portions of the project. Utilities staff will continue to research these opportunities.
The actual construction at the treatment plant would not begin until 2019, once the plant project is approved by the Municipal Utilities Commission, and staff would have time to research and apply for grants.
The original $4.2 million project needs to be done, Braegelman said. Whether additional upgrades are completed depends on finding funding.
As utility staff research grant opportunities and the public is educated on high-efficiency softeners, both the city and the Municipal Utilities will continue to monitor the situation, to see if the discharge numbers are going down.
"Hopefully we'll have an idea if it is working. We're going to have to monitor it," Braegelman.
If the plant upgrades and public assistance are not enough, there is another option the utilities would have to greatly reduce the salty discharge. It could soften the city's water before it gets to customers. This would remove the need to home treat water, and greatly diminish the amount of salty minerals entering the water. However, that option would be very expensive.
Just to build softening plants at the northeast and southwest water plants would cost over $2 million each. Then it would cost another $2 million per year to operate the plants, not including labor, to soften all the city's water.
Because of the cost of this option, Harren is hoping that greater public use of high-efficiency softeners and the completion of the treatment plant project will do enough for the city to meet the MPCA requirements.
"If we all work together, it will be the most cost-effective way," Harren said.