Policy recommendations for reducing reactive nitrogen from wastewater treatment in the Great Bay Estuary, NH

► Modeled cost of sewage treatment facilities to reduce reactive nitrogen. ► We examined changes in cost due to alternative policy structures. ► Alternative policy reduces nitrogen in aggregate, but localized pollution remains. ► Increasing the number of regional trading partners will increase the cost-savings. ► In the short term, an 8 mg N/L concentration suffices, but in the long term, 5 mg N/L.