Higher DNR limits
Village phosphorus caps are increased
The Wisconsin Nature Resources Board on Oct. 28 agreed to new phosphorous criteria on Lakes Petenwell, Castle Rock and Wisconsin, saving municipalities millions of dollars in treating sewage.
The board voted unanimously to increase the phosphorus targets in Lakes Petenwell and Castle Rock from 40 micrograms per liter to 53 and 55, respectively, and lower the limit in Lake Wisconsin from 100 to 47 micrograms per liter.
The new limits mean the villages of Athens, Edgar and Marathon City will not, as part of Total Maximum Daily Load project, have to remove as much phosphorus from their wastewater treatment effluent as been previously announced.
The new, higher limits, said the DNR, will save 19 municipal treatment plants in the Wisconsin River Basin $73.2 million in capital costs and $1.2 million annually in sewage plant operating costs.
The DNR estimates savings for two local villages:
_ Village of Edgar, $2.3 million in capital costs and $23,000 a year in operating costs. The village’s annual phosphorus discharge limit will increase from 300 to 492 pounds per year.
_ Marathon City, $1.9 million in capital costs and $19,000 a year in operating costs. The village’s phosphorus discharge limit will increase from 211 to 383 pounds per year.
The DNR said that the Village of Athens will see its discharge limit increase from 112 to 203 pounds, but, because the village needs to update its lagoon-style treatment plant, the agency did not forsee the village saving any money.
The village of Stratford, which discharges effluent to the Big Eau Pleine watershed and not to the Wisconsin River, is unaffected by the DNR board’s action.
DNR water evaluation section chief Marcia Willhite told board members the overall less restrictive targets would still reach the agency goal of reducing algae blooms on the three lakes.
She said that even the higher goals will still be difficult to attain.
“It will be a big lift if we were to target [the lakes] at 53 or 40 [micrograms per liter],” she said. “We will be reducing phosphous to half of what it is now. It will be a lot of work.”
Willhite told the board it would take at least a decade before lowered municipal discharges will have any affect on phosphorus levels in the lakes. She said it could take even longer for nonpoint phosphorus runoff, including farm runoff, to be decreased. The DNR is relying on farmer voluntary efforts to lower phosphorus discharge from cropland and barnyards.
Village of Marathon City administrator Andy Kurtz said the board’s action was anticipated but won’t mean anything until the site specific criteria are approved by Region Five EPA. That could take 12-18 months, he said.
Kurtz said the village’s wastewater treatment plant permit will likely be renewed by DNR in 2020 and the village will need to meet a phosphorus discharge limit.
He said the village has in place a plan to pay MilTrim Farms, Athens, $50 a pound for 475 pounds of phosphorus credits as part of a Multi-Variance Discharge (MDV) watershed plan. The farm will earn the credits through no-till crop farming and use of cover crops.
Kurtz said the village will be able to use the MDV plan for approximately five years, unless EPA agrees to re-authorize it.
The administrator said paying for farmer phosphorus credits is cheaper than installing a $3.5 million filtration system to remove phosphorus from the village’s wastewater discharge.
He noted that the phosphorus credits would be cheaper, in fact, than paying the interest on such a project.