Hundreds of wastewater treatment facilities throughout the Chesapeake Bay region are being upgraded to reduce the amount of nutrients flowing into local waterways.


  • What is wastewater?

    Wastewater is all the used water that originates from households—toilets and bathroom fixtures, kitchens, laundry, lawn and garden irrigation, swimming pools—as well as from industrial, commercial and agricultural activities and polluted runoff.

  • How does wastewater affect the Chesapeake Bay?

    Depending on the source, some wastewater can contain nutrient or sediment pollution, or dissolved chemical contaminants. If left untreated, those pollutants can cause harm to waterways, wildlife or humans when released back into the environment.

  • How many wastewater treatment plants are there?

    The Chesapeake Bay region is home to 472 municipal and industrial wastewater treatment plants.

  • What pollutants are found in wastewater?

    Depending on the source, some wastewater can contain nutrient or sediment pollution, or dissolved chemical contaminants.

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  • Anoxia

    A condition in which little or no oxygen is present in a body of water. Also called a “dead zone.”

  • Biological nutrient removal (BNR)

    Wastewater treatment technology that uses microorganisms to remove nitrogen and phosphorous from effluent.

  • Chemical contaminants

    Pesticides, pharmaceuticals, metals and other toxic substances that can harm the health of both humans and wildlife.

  • Denitrification

    The loss or removal of nitrogen or nitrogen compounds.

  • Enhanced nutrient removal (ENR)

    Wastewater treatment technology that improves upon the nutrient reductions achieved through biological nutrient removal (BNR).

  • Nitrification

    The process by which ammonia is oxidized into nitric acid or another nitrate or nitrite. Biological nitrification is a key step in the removal of nitrogen from wastewater.

  • Nutrient removal technology (NRT)

    Technology that removes nitrogen and phosphorus during wastewater treatment. Also known as biological nutrient removal (BNR).

  • Nutrients

    Chemicals that plants and animals need to grow and survive but, in excess amounts, can harm aquatic environments. Elevated levels of the nutrients nitrogen and phosphorous are the main cause of poor water quality in the Chesapeake Bay.

  • Pollution

    The introduction of harmful substances or products into the environment.

  • Tributary

    A creek, stream or river that flows into a larger body of water. For example, the Susquehanna, Potomac and James rivers are tributaries of the Chesapeake Bay.

  • Wastewater

    Water that has been used in homes, industries and businesses that is not for reuse unless treated by a wastewater treatment facility.

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