Serving Northern St. Louis County, Minnesota

No easy path forward for wastewater expansion

High cost of new treatment capacity could limit new development in Tower

Marshall Helmberger
Posted 12/6/19

TOWER-SOUDAN— An expansion of the wastewater treatment system that serves these two communities appears to be out of the question, due to cost, and that could well have repercussions for the …

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No easy path forward for wastewater expansion

High cost of new treatment capacity could limit new development in Tower

Posted

TOWER-SOUDAN— An expansion of the wastewater treatment system that serves these two communities appears to be out of the question, due to cost, and that could well have repercussions for the future of commercial and residential development in the two communities.
Without a path forward, that either expands sewage treatment capacity, or reduces the flow to make room for new development, future projects here may require developers to rely on individual septic systems.
That’s according to Matt Tuchel, system operator of the Tower-Breitung Wastewater Board (TBWB), who spoke on the topic following last month’s wastewater board meeting.
The two communities have been approaching the limits of their wastewater capacity for some time, but the issue came to a head in 2018 when officials in Tower opted to connect the Hoodoo Point Campground to the municipal treatment system. That decision consumed most of the remaining wastewater treatment capacity, prompting TBWB officials to explore a possible expansion. The board did commission an effluent study by the Minnesota Pollution Control Agency last year, which suggested that an expanded system would likely be allowed no additional discharge of phosphorus than at present. Meeting that standard would almost certainly require mechanical treatment, said Tuchel, which would involve a capital investment of up to $10 million and would significantly increase operating and maintenance costs for the system. The TBWB currently relies on sewage ponds, which are much more affordable to operate. Yet ponds are not as effective as mechanical treatment for reducing phosphorus, which is a nutrient that commonly encourages algae growth in lakes. Effluent from the TBWB system eventually flows into Lake Vermilion’s Pike Bay, which makes any possible increase in phosphorus discharge a sensitive issue.
What’s more, Tuchel said, an expansion would put the system at over 200,000 gallons per day, a threshold that brings additional regulatory requirements, such as a need to at least test mercury levels. That could further increase the costs associated with an expansion, perhaps considerably.
The MPCA has already given the greenlight for the planned town home development at the city’s harbor, which has been factored into the existing treatment capacity, so the capacity issue is unlikely to complicate that project, which has been mired in a series of delays over platting.
But any additional major new project, such as a new hotel or sizable residential development, will likely need to develop its own wastewater treatment system, which could complicate efforts to bring new development to Tower.
The high cost of building additional capacity is putting new focus on efforts to reduce flow, mostly through the reduction of inflow and infiltration, or I and I, of ground and surface water into the system. Despite significant efforts to reduce I and I a decade or more ago, the problem continues to add as much or more to the wastewater flow as comes from actual users of the system, based on previous estimates.
Inflow and infiltration can be a substantial contributor to wastewater flows and the recent connection of the Hoodoo Point Campground is further adding to the problem. The sewer work did update portions of that system, but it did not address aging sewage collection lines that serve some of the campground’s RV sites. According to TBWB flow data, the campground is now generating more than 450,000 gallons of flow (or nearly 2,500 gallons per day) during the winter months when the campground is closed and water is disconnected. “That has to be I and I,” said Tuchel.
While flow is somewhat higher during the summer months, the data suggests that the actual effluent flow from the campground is limited to approximately 1,500 gallons per day or less. That’s far less than the capacity of the campground’s commercial mound system, that continues to serve the airport. That triple mound system was designed to accommodate up to 9,500 gallons of effluent flow. The city, at a cost of approximately $500,000, disconnected the campground from that system last year and extended a municipal sewer line to the campground, instead.
Attention shifts to drinking water quality
With the prospect of new treatment capacity on the back burner for now, the TBWB has focused its efforts on improving the quality of the communities’ water and replacing an aging water main that connects the water plant to customers in the city of Tower. TBWB officials have been working to find grant dollars to help cover the cost of those planned upgrades, which are expected to run a combined $2.3 million.
Tuchel has also been dealing with the aftermath of a lightning strike at the water plant back in September, which blew out an automatic control panel, forcing Tuchel to operate the facility manually for weeks while waiting for repairs. He has since been awarded a letter of commendation for his extraordinary efforts to maintain the water source for both Tower and Soudan.

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