Water Pollution

advanced sewage treatment
Specialized chemical and physical processes that reduce the amount of specific pollutants left in wastewater after primary and secondary sewage treatment. This type of treatment usually is expensive. See also primary sewage treatment, secondary sewage treatment.
biological oxygen demand(BOD)
Amount of dissolved oxygen needed by aerobic decomposers to break down the organic materials in a given volume of water at a certain temperature over a specified time period.
cultural eutrophication
Overnourishment of aquatic ecosystems with plant nutrients (mostly nitrates and phosphates) because of human activities such as agriculture, urbanization, and discharges from industrial plants and sewage treatment plants. See eutrophication.
dissolved oxygen DO content
Amount of oxygen gas (O2) dissolved in a given volume of water at a particular temperature and pressure, often expressed as a concentration in parts of oxygen per million parts of water.
eutrophication
Physical, chemical, and biological changes that take place after a lake, estuary, or slow-flowing stream receives inputs of plant nutrients[[emdash]]mostly nitrates and phosphates[[emdash]]from natural erosion and runoff from the surrounding land basin. See cultural eutrophication.
nonpoint source
Large or dispersed land areas such as crop fields, streets, and lawns that discharge pollutants into the environment over a large area. Compare point source.
oxygen-demanding wastes
Organic materials that are usually biodegraded by aerobic (oxygen-consuming) bacteria if there is enough dissolved oxygen in the water. See also biological oxygen demand.
point source
Single identifiable source that discharges pollutants into the environment. Examples are the smokestack of a power plant or an industrial plant, drainpipe of a meatpacking plant, chimney of a house, or exhaust pipe of an automobile. Compare nonpoint source.
primary sewage treatment
Mechanical sewage treatment in which large solids are filtered out by screens and suspended solids settle out as sludge in a sedimentation tank. Compare advanced sewage treatment, secondary sewage treatment.
secondary sewage treatment
Second step in most waste treatment systems in which aerobic bacteria decompose up to 90% of degradable, oxygen-demanding organic wastes in wastewater. This usually involves bringing sewage and bacteria together in trickling filters or in the activated sludge process. Compare advanced sewage treatment, primary sewage treatment.
septic tank
Underground tank for treating wastewater from a home in rural and suburban areas. Bacteria in the tank decompose organic wastes, and the sludge settles to the bottom of the tank. The effluent flows out of the tank into the ground through a field of drainpipes.
sludge
Gooey mixture of toxic chemicals, infectious agents, and settled solids removed from wastewater at a sewage treatment plant.
water pollution
Any physical or chemical change in surface water or groundwater that can harm living organisms or make water unfit for certain uses.
organic chemicals
to be any that has a carbon-carbon or a carbon-hydrogen bond
heavy metals
A metal with a specific gravity greater than about 5.0, especially one that is poisonous, such as lead or mercury
inorganic chemicals
Any substance in which two or more chemical elements other than carbon are combined, nearly always in definite proportions (see bonding), as well as some compounds containing carbon but lacking carbon-carbon bonds
fecal coliform test
for E. coli. It was designed to reduce or eliminate all gram negative colifrom
Clean Water Act 1972, 1977
Passed in 1972 and amended in 1977 and 1987, the Clean Water Act was originally known as the Federal Water Pollution Control Act. The Clean Water Act is administered by the U.S. Environmental Protection Agency (EPA), which sets water quality standards, handles enforcement, and helps state and local governments develop their own pollution control plans.
Safe Drinking Water Act
To achieve its goal the SDWA provides water quality standards for drinking-water suppliers, protects underground drinking-water sources, and directs appropriate deep-well injection of wastes.
Water Quality Act
see clean water act
wetlands
An area characterized by a high content of soil moisture, such as a swamp or bog.
cholera
acute illness characterized by watery diarrhea that is caused by the bacterium Vibrio cholerae. Cholera is spread by eating food or drinking water contaminated with the bacteria.
oxygen sag curve
The curve obtained when the concentration of dissolved oxygen in a river into which sewage or some other pollutant has been discharged is plotted against the distance downstream from the sewage outlet
feedlot runoff
are integrated structures and practices for collecting, storing and treating livestock manure and feed wastes to reduce runoff and water pollution. Controlling runoff from feedlots, barnyards and other livestock facilities helps prevent excess nutrients and pathogens from reaching rivers, streams and lakes.
oligotrophic
Lacking in plant nutrients and having a large amount of dissolved oxygen throughout. Used of a pond or lake.
plume
A space in air, water, or soil containing pollutants released from a point source.
HAB
dense spread of algae which results from changes in the chemistry and/or temperature of lake water. Blooms may be green or red, and are most common in spring or early summer, when primary production outstrips the growth of the consumer organisms.
Exxon Valdez
ship gained infamy after the March 24, 1989 oil spill in which the tanker, captained by Joseph Hazelwood and bound for Long Beach, California, hit Prince William Sound‘s Bligh Reef and spilled an estimated minimum 10.8 million US gallons (40.9 million litres) of crude oil.