A Minnesota Court of Appeals ruling has upheld stricter water quality standards the state approved last year, which may cause cities to pay for upgrades to their treatment plants.
In Monday's ruling, a three-judge panel said the new standards are valid, disagreeing with cities and soybean farmers who argued the rulemaking process was flawed.
As MPR News explains, the tighter rules involve what scientists call eutrophication standards, which are measured by combining phosphorus, chlorophyll, and oxygen levels.
The Minnesota Pollution Control Agency has identified phosphorus as a contributor to excessive algae in Minnesota waterways. Too much algae in a lake or river can suffocate the fish and other aquatic life there, the agency says.
The MPCA says the amount of phosphorous in Minnesota waters began declining after regulators imposed limits on how much of it treatment plants can release.
Cities object to cost
But in announcing the lawsuit last fall, the president of the Coalition of Greater Minnesota Cities said the stricter standards go too far.
The environmental coordinator for the Rochester Water Reclamation Plant, David Lane, told the Pipestone County Star the MPCA's lower standard means chemical treatment of phosphorus will no longer be sufficient and plants will need to upgrade their filtration systems.
Lane told the Star in December he estimated the change would cost Rochester $100 million over 20 years, split evenly between construction and operating costs.
Moorhead and Marshall are among other cities that anticipate higher costs.
MPR reports one of the groups that filed the lawsuit said Monday it was disappointed by the appeals court ruling but had not decided whether to appeal to the Minnesota Supreme Court.
The 2014 rules that were challenged involve standards about what treatment plants release into rivers and streams – a separate set of rules applies to lakes.