NEW RICHMOND -- The City Council unanimously adopted Resolution 012002 approving a wastewater facility plan which confirms the existing wastewater treatment plant (WWTP) -- originally constructed in 1981 and consequently upgraded in 1999 and again in 2010 and 2013 -- has the capacity to meet the city’s growing wastewater needs. With one exception: phosphorus.
“The facility plan looks ahead 20 years at what the population will be and what the flows and loads are going to be associated with that growth. What we came up through our population projection was that, really the plant is sufficient from a capacity standpoint to handle what we think the flows and loads are going to be,” Public Works Director Jeremiah Wendt said at Monday's meeting. "But there are some things we need to do to meet the phosphorus limit and to keep the plant operating that long."
As part of the Department of Natural Resource's Wisconsin Pollutant Discharge Elimination System permitting program, the city’s 2018 permit lowers its wastewater treatment facilities effluent phosphorus limit from 1.0 mg/L to 0.075 mg/L. The permit term is for five years.
Wendt explained that depending on the solution to achieve the new stricter limit, the city would have the current permit term plus the next term until 2027 to achieve the new limit and possibly one more permit term of five more years if needed.
The DNR provides three options for compliance with the strict new phosphorus effluent requirements:
1) technology upgrades, typically tertiary filtration and chemical addition at the treatment plant;
2) adaptive management within the basin to reduce in stream phosphorus levels below an established in stream threshold (0.075 mg/L in the case of the Willow River watershed);
3) phosphorus trading with area agricultural concerns to offset the amount of phosphorus discharged by the facility above the permitted level.
A water quality or phosphorus trading solution would allow the city to continue to discharge phosphorus into the watershed but for every pound it discharges it must pay a farmer or some other concern in the watershed to implement conservation practices on their field that’s going to keep more than that pound of phosphorus on their field and out of the watershed.
After considering a number of ways to achieve the 0.075 mg/L limit, staff recommended a hybrid approach, namely initiate an adaptive management program with the aim or possibility of transitioning to a trading program.
The aim is to use the first five-year permit term to begin to develop partnerships within the basin and to find incentives for farmers and other agricultural concerns to adopt conservation measures to reduce phosphorus.
“We’re going to be continually implementing practices in the watershed to reduce that phosphorus load to improve the quality of the surface water,” said Wendt.
Once partnerships and projects are solidified, if the phosphorus levels are not within the compliance range, the city could transition to a trading program with those partners.
There is no guarantee this approach will achieve the mandated phosphorus limits, but Wendt made the case that it is fiscally responsible and flexible allowing New Richmond to comply with the DNR’s design deadline while providing an initial direction and the option to change direction if one approach is not succeeding or implement new technology as it is developed.
Equipment and safety upgrades to the WWTP scheduled to be constructed in 2020-2021 will cost the City $3.3 million. The Utility is planning to pursue a Clean Water Fund loan from the Wisconsin DNR to finance the physical improvements to the WWTP. Repayment of the loan has been figured into the new sewer rate.
The adaptive management plan anticipates the City will spend $422,000 in capital expenses and $258,000 in operating and maintenance costs to meet the phosphorus limit, however these costs would be incurred beginning in 2023 at the earliest.
The facility plan was paid for by mitigation funds provided by the St. Croix Crossing project at a cost of $49,500.