Money generated by the Clean Water Legacy Amendment is helping reduce algae-causing phosphorus in Minnesota waters via grants to improve wastewater treatment. Since 2010, $20 million in Clean Water Fund grants have helped 30 municipalities finance upgrades to their wastewater treatment facilities. Through these upgrades, the facilities were able to meet state-mandated reductions in phosphorus discharges.
Altogether, these plants have reduced phosphorus in wastewater discharges by 120,000 pounds a year. That means 2.4 million pounds total of phosphorus removed over the plants’ life expectancy of 20 years.
The Clean Water Fund grants leveraged an additional $56 million in other funding for these infrastructure improvements.
One example of this effort is the city of Cambridge that used a Clean Water Fund grant to upgrade its wastewater treatment facility. This city of 8,200 in Isanti County discharges its treated wastewater to the Rum River, which is designated as an Outstanding Resource Value water and needs protection because of its exceptional quality. The facility was overloaded hydraulically and organically, and faced site restrictions because of its location on the river. In addition, the MPCA set tighter limits on phosphorus discharges.
The city of Cambridge designed a new facility to improve wastewater treatment and developed a system to work with existing equipment to increase operator control, process flexibility, and resource conservation at a reasonable cost. The treatment upgrades resulted in a 92-percent reduction — 10,451 pounds per year — in phosphorus discharged to the Rum River.
The entire project costs about $15 million. The phosphorus reduction portion costs about $2.7 million, of which state funding provided $1.37 million.
Statewide, municipal wastewater phosphorus discharges have decreased by 70% during the past 15 years. Overall, efforts have led to a steady decline of phosphorus pollution and major improvements in water quality. Implementation of newly adopted river nutrient standards is expected to drive further reductions in wastewater phosphorus loads in coming years.
See more information about Clean Water funding for wastewater treatment in the 2016 Performance Report.
While wastewater plays an important role in reducing nutrient pollution, achieving and maintaining healthy waters will require action from all sources, including farmland, rural areas and urban centers.