Activated Sludge is produced by mixing primary effluent with bacteria-laden sludge in a process that is activated using aeration and agitation to promote biological treatment.
Advanced Waste Treatment is wastewater treatment beyond the secondary or biological stage of treatment. It includes the removal of nutrients such as phosphorus and nitrogen and a high percentage of suspended solids. It is also often called tertiary treatment.
Aerobic refers to life or processes that require the presence of free elemental oxygen.
Aeration is the process of exposing something to circulating air.
Anaerobic refers to life or processes that require the absence of free elemental oxygen.
Bacteria are single-cell microscopic organisms that grow in nearly every environment on Earth. In wastewater treatment, they can perform a variety of biological treatment processes, including biological oxidation, sludge digestion, nitrification and denitrification.
Biochemical Oxygen Demand (BOD) is the measure of the amount of oxygen consumed in the biological processes that break down organic matter in water. The greater the BOD, the greater the degree of pollution.
Biosolids are the primarily organic solid product of wastewater treatment processes and can be beneficially recycled or appropriately disposed of via landfilling or incineration.
Combined Sewer is a sewer system that carries both sanitary sewage and stormwater runoff.
Denitrification is the reduction of nitrate nitrogen to nitrogen gas.
Effluent is wastewater, treated or untreated, that flows out of a treatment plant, sewer or industrial outfall.
I and I (I/I) is short for infiltration and inflow (see below).
Infiltration is entry of water into a sewer system through such sources as defective pipes, pipe joints, connections or manhole walls.
Inflow is entry of water into a sewer system from sources other than infiltration, such as basement drains, storm drains and street washing.
Influent is water, wastewater, or other liquid flowing into a reservoir, basin, treatment plant or treatment process.
Infrastructure in the wastewater treatment industry refers to the expansive network of reservoirs, plants and pipes above and/or below ground that provides, processes and treats our water.
Land Application is the treatment or disposal of wastewater or wastewater solids by spreading it on land under controlled conditions.
Membranes are soft, pliable sheets or layers that can be used in filtration processes. Membrane Bioreactors combine activated sludge treatment processes and membrane filtration equipment to separate liquids and solids.
Microconstituents are trace complex organic compounds, generally from industrial, medicinal, pharmaceutical, and personnel care products, but may also be naturally occurring. They are sometimes called compounds of emerging concern (CECs) or endocrine disrupting compounds (EDCs).
Microorganisms are microscopic organisms, either plant or animal, invisible or barely visible to the naked eye, for example, bacteria, fungi, protozoa, and viruses.
National Pollution Discharge Elimination System (NPDES) is the permit process established under the Clean Water Act that requires municipal and industrial wastewater treatment facilities to obtain permits that specify the types and amounts of pollutants that may be discharged into water bodies.
Nitrification is the oxidation of ammonia nitrogen to nitrate nitrogen in wastewater by biological chemical reactions. Nutrients are elements or compounds, such as nitrogen, phosphorus, and potassium that are necessary for plant growth.
Operations and Maintenance (O&M) is the organized procedure for causing a piece of equipment or a treatment plant to perform its intended function and for keeping the equipment or plant in such a condition that it is able to continually and reliably perform its intended function.
Permit is a legal document issued by a government agency. In wastewater treatment, a discharge permit requires that the plant operator achieve specific water quality standards and discharge limits and also establishes monitoring and reporting requirements.
Preliminary Treatment is the initial treatment process within a treatment plant where solids from the incoming influent are removed to enhance further treatment processes and future prevent damage to equipment.
Primary Treatment is the stage in wastewater treatment where screens and sedimentation tanks are used to remove most material that floats or will settle. Primary treatment results in the removal of a substantial amount of suspended matter but little or no dissolved matter.
Receiving Stream is a river, lake, ocean or other watercourse into which wastewater or treated effluent is discharged.
Sanitary Sewer is a sewage system that carries only household, commercial, and industrial wastewater.
Secondary Treatment is the phase in the waste-water treatment process where bacteria are used to digest organic matter in the wastewater. Sometimes the term is used interchangeably with the concepts of biological wastewater treatment. Sludge is solid matter that settles to the bottom of septic tanks or the material that results from wastewater treatment plant sedimentation.
Suspended Solids are solid pollutants that either float on the surface of or are suspended in wastewater primarily due to their small size. They can also be called total suspended solids (TSS).
Ultraviolet Disinfection is the process of using ultraviolet light to kill disease-causing bacteria and viruses. User Charges are charges billed to users of water and wastewater systems for services supplied.
Wastewater is used water from a community or industry that contains dissolved or suspended matter.