Regulatory certainty is an incentive for municipalities that will employ biological nutrient removal in their wastewater treatment technology, and that are willing to accept a nitrogen limits in advance of a nitrogen standard. It affords up to 20 years of no more-restrictive phosphorous and nitrogen effluent limits allowing greater certainty in future fiscal planning and economic development. Minnesota has water quality standards for phosphorus and is working on standards for nitrogen. Both these nutrients can cause algal blooms harmful to aquatic life and recreation. Nitrogen can also be toxic to fish and other aquatic life, as well as harmful to humans in drinking water.
This approach takes the uncertainty out of planning for facilities needing to upgrade or build systems to comply with phosphorus limits. By incorporating nitrogen removal too, they can avoid higher costs to comply with new standards in 5-10 years.
Regulatory certainty also allows Minnesota to start reducing nitrogen discharged by wastewater treatment facilities ahead of adopting a standard. Minnesota finalized a statewide Nutrient Reduction Strategy in 2014 that calls for a 45% reduction in nutrients in the Mississippi River Basin by 2040 to protect downstream waters all the way to the Gulf of Mexico. For phosphorus, that’s a reduction from 4,600 tons per year to 2,500 tons, and for nitrogen, 91,000 tons a year to 50,000 tons. This strategy includes an interim reduction goal for the Mississippi River of 20% by 2025.
Instead of waiting for the nitrogen standard to be developed and mandated, the regulatory certainty approach helps Minnesota take action now to protect lakes and rivers here as well as downstream.