Glossary

Clean Water Act

Approved by Congress in 1972, the Clean Water Act established the basic structure for regulating discharges of pollutants into the waters of the United States.

Consent Decree

The legally binding document that represents the result of negotiations between the U.S. Department of Justice and the State of Tennessee. It specifies the activities and timetables required to address within the City of Memphis.

Erosion

The degradation or displacement of the upper layer of soil by the action of natural (e.g., water, ice, snow, air, plants, animals) or man-made disturbances. Erosion – natural or man-made – can impact water quality.

Fully Treated Effluent

Water taken from any waste stream and treated to a high standard so it can be used for a new activity or discharged into receiving waters.

Grease Blockage

A blockage in a sewer pipe is caused by the accumulation of fats, oils, and/or grease.

Infrastructure Renewal

Upgrading, enhancing, and/or improving the fundamental facilities and systems serving a country, city, or area such as water/wastewater, transportation, and communication systems; power plants; and schools.

Infiltration

Infiltration refers to rainwater and groundwater that enters the sanitary sewer system. A certain amount of infiltration is unavoidable and is accounted for in routine sewer design. However, when infiltration exceeds design allowances, sewer capacity is consumed and may result in overflows, risks to health, damage to the environment, and increased conveyance costs.

Inflow

Water other than wastewater that enters the separate sanitary or combined sewer system from sources such as, but not limited to, roof leaders, cellar drains, yard drains, area drains, drains from springs and swampy areas, manhole covers, cross connections between storm sewers and sanitary sewers, catch basins, cooling towers, stormwater, surface runoff, street wash waters, or drainage. A certain amount of inflow is unavoidable and is accounted for in routine sewer design. However, when inflow exceeds design allowances, sewer capacity is consumed and may result in overflows, risks to health, damage to the environment, and increased conveyance costs.

National Pollutant Discharge Elimination System (NPDES) Permit

The NPDES permit program addresses water pollution by regulating point sources that discharge pollutants to waters of the United States.

Sanitary Sewer Overflows

Sanitary Sewer Overflows are a condition where untreated sewage is discharged into the environment prior to reaching sewage treatment facilities. The main causes include: grease/rags blockages, infiltration of excessive stormwater into sewer lines during heavy rainfall; rupture or blockage of sewerage lines; malfunction of pumping station lifts, or electrical power failure.

Separate Storm Sewer System

The City also has a system of culverts, drains, and pipes to carry stormwater to streams and rivers. Stormwater is rainwater that runs off rooftops, streets, and parking lots. The separated storm sewer system collects the rainwater and snow melt from street catch basins, and roof drains and carries it directly to the receiving waters.

Street Catch Basin

An opening to the storm drain system that typically includes a grate or curb inlet at street level where stormwater enters the catch basin, and a sump captures sediment, debris, and associated pollutants. Catch basins are able to prevent trash and other floatable materials from entering the drainage system by capturing such debris by way of a hooded outlet.

Wastewater Treatment Plant (WWTP)

A facility designed to remove contaminants from municipal wastewater and convert it into an effluent that can be returned to the water cycle with minimum impact on the environment.

Wastewater Collection and Transmission System (WCTS):

The municipal wastewater collection, retention, and transmission system, including all pipes, Force Mains, Gravity Sewer Lines, Lift Stations, pumps, manholes, and appurtenances thereto, which are owned or operated by Memphis and service Memphis and which flow to the M.C.Stiles and T.E. Maxson WWTPs.