Research and Reports on Nutrient Pollution
EPA supports research and publication of basic and applied science topics that explore solutions to reduce nutrient pollution in surface and source waters. The Agency also facilitates access to relevant research and policy publications.
EPA Nutrient Research
EPA's Office of Research and Development (ORD) conducts research on topics associated to nutrient pollution. ORD researchers are exploring solutions to identify nutrient and HABs sources, map and model their distribution to better understand their effects on human health and the environmental, maximize efficient nutrient use, and promote nutrient removal among others. ORD provides programmatic support to CWA and SDWA programs by supporting the development of regulatory limits for nutrients and facilitating the understanding of the social and economic costs and benefits associated with management alternatives and their achievability.
Life Cycle Assessment of Upgrade Options to Improve Nutrient Removal for the City of Santa Fe, NM, Paseo Real Wastewater Treatment Plant (January 2023)
Life cycle assessment (LCA) is a standardized method for evaluating the environmental impacts and benefits of a product or process over its full life cycle. An LCA helps regulators, decision-makers, stakeholders, and the public holistically understand the environmental outcomes of different options for manufacturing a product, or building and operating a process in terms of their environmental trade-offs.
This report is a case study application of EPA’s 2021 LCA report. The report presents the results of an LCA of several options for process optimization and treatment upgrades to meet more stringent effluent nutrient limitations at the Paseo Real wastewater treatment plant which serves the City of Santa Fe, New Mexico.
- Final report: Life Cycle Assessment of Upgrade Options to Improve Nutrient Removal for the City of Santa Fe, NM, Paseo Real Wastewater Treatment Plant (pdf)
- Presentation: Santa Fe Wastewater Treatment Plant Life Cycle Assessment (LCA) (pdf)
- Fact Sheet: Understanding the Environmental Trade-Offs of Wastewater Treatment Options: An Introduction to the Life Cycle Assessment Approach (pdf)
Life Cycle and Cost Assessments of Nutrient Removal Technologies in Wastewater Treatment Plants (August 2021)
Human-caused nutrient enrichment of waterbodies from excessive nitrogen (N) and phosphorus (P), also known as nutrient pollution, is one of the most pervasive environmental issues facing the United States. In many watersheds, municipal and industrial wastewater treatment plants (WWTPs) can be major point sources of nutrients. Recent efforts to derive numeric nutrient criteria to protect the designated uses of waterbodies have resulted in limits that may be challenging to meet for most WWTPs in the United States with the treatment configurations currently in place. However, many stakeholders have expressed concern that there may be significant undesirable environmental and economic impacts associated with upgrading treatment configurations, as these configurations may require greater use of chemicals and energy, release more greenhouse gases, and generate greater volumes of treatment residuals for disposal.
These impacts can be assessed using holistic, systematic approaches such as life cycle impact assessment (LCIA) and life cycle cost analysis (LCCA). These approaches provide a “cradle-to-grave” analysis of the environmental impacts and benefits as well as the economic costs and benefits associated with individual products, processes, or services throughout their life cycle. This study used LCIA and LCCA approaches to assess cost, human health, and ecosystem metrics associated with nine distinct wastewater treatment configurations designed to reduce the nutrient content of effluent from municipal WWTPs.
- Life Cycle and Cost Assessments of Nutrient Removal Technologies in Wastewater Treatment Plants – 2023 update (with errata) (pdf)
- Life Cycle and Cost Assessments of Nutrient Removal Technologies in Wastewater Treatment Plants – Errata (pdf)
- Life Cycle and Cost Assessments of Nutrient Removal Technologies in Wastewater Treatment Plants (pdf)
Innovative Nutrient Removal Technologies: Case Studies of Intensified or Enhanced Treatment (August 2021)
EPA completed a study and report that analyzed the long-term performance of five facilities in the U.S. and one facility in Canada that implemented innovative technologies or process enhancements designed to significantly intensify treatment or enhance the removal of nitrogen or phosphorus species. The analysis centered on assessing technology performance and statistical variability of plant effluent nutrient concentrations over a three-year period. Each case study presents a detailed process description, performance analysis, assessment of process train consistency in meeting permit limits, and lessons learned in process implementation.
- Innovative Nutrient Removal Technologies: Case Studies of Intensified or Enhanced Treatment (pdf) (August 2021, EPA 830-R-01-001)
Compendium of State and Regional NPDES Nutrient Permitting Approaches (January 2021)
Excess nutrient loading to water bodies beyond levels needed to maintain the health of an indigenous aquatic ecosystem is commonly referred to as nutrient pollution. The effects of nutrient pollution are diverse and far-reaching. Among the most significant and widespread effects of nutrient pollution are accelerated eutrophication and the resulting impacts on water quality.
The National Pollutant Discharge Elimination System (NPDES) program, requires permits for any point source discharge of pollutants to waters of the United States. Point sources regulated by the NPDES program that discharge nutrients include municipal and industrial wastewater treatment plants, concentrated animal feeding operations (CAFOs), Municipal Separate Storm Sewer Systems (MS4s), stormwater associated with industrial activity, and various other potential sources of nutrient pollution.
This compendium is a collection of state practices, policies, and procedures for reducing excess nutrients. Its purpose is to facilitate state-to-state sharing about different approaches for addressing the adverse effects of excess nutrients in NPDES permits. This compendium showcases nutrient-specific procedures employed by authorized NPDES state and regional permitting authorities. It is divided into the following sections: Permitting Critical Conditions, Performance Based Approaches, Water Quality Trading, and Watershed-Based Permitting. This compendium is designed to be a “living document” that can be updated as needed; future updates may include topics such as variances, adaptive management, implementation of narrative criteria, and implementation of nutrient TMDLs.
- Compendium of State and Regional NPDES Nutrient Permitting Approaches (pdf) (January 2021, EPA 833-B-21-001)
Case Studies on Implementing Low-Cost Modifications to Improve Nutrient Reduction at Wastewater Treatment Plants (August 2015)
Nutrient pollution is one of America’s costliest and most challenging environmental problems. However, many of the nation’s wastewater plants were not designed for nutrient removal and major retrofits may be a significant hurdle.
This report showcases communities where lower cost plant modifications can reduce nutrient discharge levels (ranging from about 20% to 70%), under specific circumstances. We found that in most cases, the activities’ effects were positive, allowing for better energy efficiency, lower operational costs and improved process performance.
EPA is interested in learning of additional communities’ successes and intends to update this document to help more of the nation’s wastewater treatment plants make progress towards additional nutrient reductions. Interested parties are invited to comment and recommend additional case studies by December 15, 2015 to POTWOptiNP@epa.gov.
- Case Studies on Implementing Low-Cost Modifications to Improve Nutrient Reduction at Wastewater Treatment Plants (pdf)
Compilation of Cost Data Associated with the Impacts and Control of Nutrient Pollution (May 2015)
This report and its associated spreadsheet compile information on the costs associated with the impacts of nutrient pollution for a number of economic sectors and the costs to control nutrient sources. For the first time, costs of both controlling and not controlling nutrients are combined in one document. This report should help water program managers, legislators, and the public understand the potential costs of action and inaction and form conclusions about appropriate management actions to address nutrient pollution.
- A Compilation of Cost Data Associated with the Impacts and Control of Nutrient Pollution (pdf)
- Compilation of cost data spreadsheet (xlsx)
Six Municipalities, One Watershed: A Collaborative Approach to Remove Phosphorus in the Assabet River Watershed (March 2015)
This case study describes the activities of a consortium of wastewater treatment facilities along the Assabet River in Massachusetts who selected four different phosphorus removal technologies and successfully lowered effluent concentrations to less than 0.1 milligrams per liter of phosphorus. Each facility examined available technologies, costs, operational concerns and other factors before choosing the best option based on its own criteria. As a result of the facilities’ actions, water quality in the river has improved; phosphorus loads to the river have decreased more than 90 percent.
- Six Municipalities, One Watershed: A Collaborative Approach to Remove Phosphorus in the Assabet River Watershed (pdf)
Reactive Nitrogen in the United States: An Analysis of Inputs, Flows, Consequences, and Management Options - A Report of the EPA Science Advisory Board (August 2011)
The Science Advisory Board Integrated Nitrogen Committee conducted a study on the sources and fate of reactive nitrogen with the purpose of addressing the overarching question of how can we protect and sustain ecosystem services, while also assuring that societal needs for food and energy are met. This Report of the EPA Science Advisory Board calls for a comprehensive an integrated approach to manage reactive nitrogen, mitigate its damage, and restore ecosystems. This report also contains recommendations on the following areas: establishing the links among source and fate of reactive nitrogen, environmental and public health problems; identify actions to support an integrated nitrogen management strategy and to reduce reactive nitrogen losses by 25 percent; and make recommendations on the research necessary to support reduction activities.
- Reactive Nitrogen in the United States: An Analysis of Inputs, Flows, Consequences, and Management Options - A Report of the EPA Science Advisory Board (pdf)
Nutrients in Estuaries - A Summary Report of the National Estuarine Experts Workgroup (November 2010)
Nutrient criteria are benchmarks that help to establish the level of nutrient pollution below which waterbodies can maintain their designated uses—primarily aquatic life and recreation. Estuaries are very complicated bodies of water, and the task of setting nutrient criteria for them, in turn, is complex. The November 2010 Nutrients in Estuaries report describes some of the current science in estuarine nutrient criteria development. It does not set criteria, nor does it recommend a single methodology for doing so. Criteria can vary from site to site and from estuary type to estuary type, and the methods for setting criteria can vary depending on both the estuary type and availability of data.
- Nutrients in Estuaries - A Summary Report of the National Estuarine Experts Workgroup (November 2010) (pdf)
State-EPA Nutrient Innovations Task Group Report (August 2009)
An Urgent Call to Action - Report of the State-EPA Nutrient Innovations Task Group is a joint State-EPA review of both existing and innovative approaches to nutrient management. In 2008, State and EPA surface water and drinking water program managers agreed to form an ad hoc Nutrient Innovations Task Group to identify and frame key nutrient issues, questions, and options on how to improve and accelerate nutrient pollution prevention and reduction at the state and national level. In this report, the task group presents a summary of scientific evidence and analysis that characterizes the scope and major sources of nutrient impacts nationally and describes the current tools and authorities used to control nutrient pollution sources. The task group concludes with findings and suggests next steps needed to better address nutrient pollution.
- An Urgent Call to Action: Report of the State-EPA Nutrient Innovations Task Group (August 2009) (pdf)
National Aquatic Resource Surveys
EPA, states, and tribes are conducting a series of surveys of the nation's aquatic resources. Often referred to as probability-based surveys, these studies provide nationally consistent and scientifically-defensible assessments of our nation's waters and can be used to track changes in condition over time.
- National Coastal Condition Assessment (NCCA)
- National Lakes Assessment (NLA)
- National Rivers and Streams Assessment (NRSA)
- National Wetland Condition Assessment (NWCA)
Power Sector Progress Reports
Find recent and historical EPA reports designed to reduce power plant emissions. These reports evaluate progress under these programs by analyzing emission reductions, reviewing compliance results and market activity, and comparing changes in emissions to changes in a variety of human health and environmental indicators.
- Nutrient Reduction Progress Tracker (pdf)
- USGS - Effects of Best-Management Practices in Eagle and Joos Valley Creeks in the Waumandee Creek Priority Watershed, Wisconsin, 1990–2007
- USGS South Carolina Water Science Center Podcast Series: GEOSMIN in South Carolina Waters, What is it?
- Assessment of the Effects of Conservation Practices on Cultivated Cropland in the Chesapeake Bay Region
- Assessment of the Effects of Conservation Practices on Cultivated Cropland in the Upper Mississippi River Basin
- Effects of Nutrient Enrichment in the Nation's Estuaries: A Decade of Change
- Scientific Assessment of Hypoxia in U.S. Coastal Waters
- USGS Circular 1350: Nutrients in the Nation's Streams and Groundwater
- Pollution in the Ocean: Highlights of the National Academies Reports (pdf)
- U.S. Commission on Ocean Policy: Chapter on Addressing Coastal Water Pollution (pdf)
- "An Ocean Blueprint for the 21st Century"
- National Research Council, Mississippi River Water Quality and the Clean Water Act: Progress, Challenges, and Opportunities (pdf)
- USGS Circular 1346: Quality of Water from Public-Supply Wells in the United States, 1993–2007
- USGS Article: Nitrate in the Mississippi River and Its Tributaries, 1980 to 2008: Are We Making Progress?
- Ecosystem services altered by human changes in the nitrogen cycle: a new perspective for U.S. decision making
- Environmental Conditions in Northern Gulf of Mexico Coastal Waters Following Hurricane Katrina (pdf)
- National Atmospheric Deposition Program Annual Summary