St. Louis Park residents and businesses continue to conserve more water, but the city still is working on a project to bring Water Treatment Plant No. 4 back online.
The city took the plant out of service last December due to concern about contaminants found in water samples taken at the plant. The city plans to build an air stripper designed to significantly lower levels of volatile organic chemicals in the water.
The city failed to obtain funding from the Legislature for the air stripper, but city officials and their consultants are finishing a design aimed at addressing the contaminants.
The shutdown of the plant has not created water shortages, according to Public Work Supt. Mark Hanson.
“We’re actually doing very well,” Hanson said. “It seems that every year through our conservation efforts and public education, our average usage goes down.”
Beyond providing water, the plant has served as one of two major wells used to control a separate group of chemicals called polycyclic aromatic hydrocarbons, or PAHs, from the former Reilly Tar & Chemical creosote plant site near Highway 7 and Louisiana Avenue. The plant is one of two primary wells that have been used to control the site contaminants.
“Even though we’re doing fine from a water capacity perspective, we would really like to get Water Treatment Plant No. 4 online because it will also assist with the gradient control,” said Hanson, referring to the system that controls contaminants from the Reilly site. “What that means is as these contaminants in the groundwater try to flow past the well, we’re literally sucking them up into the well, filtering them out with the treatment processes and then providing that benefit to the environment.”
Although Water Treatment Plant No. 1 is currently fulfilling that role, bringing Water Treatment Plant No. 4 back into service would provide redundancies, Hanson said.
Although the Legislature did not provide direct funding for the project, the Minnesota Pollution Control Agency took on the cost of designing 90 percent of the project’s design before turning the plans over to the city.
The St. Louis Park City Council approved a contract with consultant AECOM to finish the design. The contract for about $333,000 includes the work on the design and construction services to ensure that a future contractor completes the project according to the bid documents AECOM will prepare.
The city plans to open bids Thursday, Sept. 21, and award the winning bid Monday, Oct. 2. Construction would begin in October with work to wrap up in fall 2018.
The total project cost is estimated at nearly $4.4 million.
The city will continue to seek funding from the Legislature.
However, Hanson said, “This year we’ve already been told there isn’t any money and next year is doubtful as well, but we are continuing to see what our chances are.”
While Hanson said utility bills would pay for the project, city leaders did not directly state whether the project would lead to an increase in rates for residents.
Finance Manager Mark Ebensteiner and Chief Financial Officer Tim Simon said in a statement, “The City anticipated issuing bonds to fund the project. Rates are analyzed and adjusted annually based on the long range financial management plan.”
The air stripper would address volatile organic chemicals that have been the main concern with the plant, but city leaders have not decided whether to add another piece of equipment that would address another form of contamination called 1, 4 dioxane. A feasibility report AECOM prepared for the city in April 2016 said that levels of the chemical at Water Treatment Plants No. 4 and No. 6 “are projected to increase in the future and require treatment” due to high levels of variability found in testing at wells within the same aquifer.
Water Treatment Plant No. 6 is no longer using water from the affected aquifer, Hanson said. The Minnesota Pollution Control Agency funded a design effort with AECOM that would allow Water Treatment Plant No. 6 to use water from the affected aquifer again, but Hanson said the council did not feel there was as much of a justification to fund it as the work on Water Treatment Plant No. 4.
The project for Water Treatment Plant No. 4 could include an Advanced Oxidation Process to treat 1,4 dioxane.
“The 1,4 dioxane is not at concerning levels right now, but the MPCA figures that in anywhere from five to 10 years it might reach levels of concern,” Hanson said.
However, he said that estimate is a guess based on the speed in which other chemicals in the area have moved. The city will study the project finances while considering whether to build the Advanced Oxidation Process or wait to determine whether 1,4 dioxane becomes a more significant problem in the future.
“Until we accept the bid, the City Council will be able to decide whether or not we want to move forward with that equipment,” said Engineering Project Manager Joseph Shamla, Sr.
Either way, the plant will be set up so that the Advanced Oxidation Process can be added later if necessary, Hanson said.
The Minnesota Department of Health has already reviewed and approved the design work the Minnesota Pollution Control Agency has performed on the project, Shamla said.
“We just need to come up with the bid documents and construction of the actual plant,” Shamla said.
Hanson added, “Every time you touch one of our treatment plants, the point we always want to make is we care deeply about providing clean safe drinking water to our residents, and this work on (Water Treatment Plant No.) 4 will allow us to do that far out into the future.”