cultural eutrophication
Near urban or agricultural areas, human activities can greatly accelerate the input of plant nutrients to a lake�a process called cultural eutrophication involving mostly nitrate- and phosphate-containing effluents from various sources.
eutrophication
the name given to the natural nutrient enrichment of a shallow lake, estuary, or slowmoving stream, mostly from runoff of plant nutrients such as nitrates and phosphates from surrounding land.
nonpoint sources
broad, and diffuse areas, rather than points, from which pollutants enter bodies of surface water or air.
point sources
discharge pollutants at specific locations through drain pipes, ditches, or sewer lines into bodies of surface water.
primary sewage treatment
Raw sewage reaching a treatment plant typically undergoes one or two levels of wastewater treatment. The first is primary sewage treatment�a physical process that uses screens and a grit tank to remove large floating objects and to allow solids such as sa
secondary sewage treatment
Raw sewage reaching a treatment plant typically undergoes one or two levels of wastewater treatment. The second level is secondary sewage treatment�a biological process in which aerobic bacteria remove as much as 90% of dissolved and biodegradable, oxygen
septic tank
In rural and suburban areas with suitable soils, sewage from each house usually is discharged into a septic tank with a large drainage field.
water pollution
any chemical, biological, or physical change in water quality that harms living organisms or makes water unsuitable for desired uses.
advanced sewage treatment
uses a series of specialized chemical and physical processes to remove specific pollutants left in the water after primary and secondary treatment
clean water act
ensures that water will meet health standards
safe drinking act
ensures that drinking water will be safe and healthy
algal blooms
red, brown, or green toxic tides
healthy zone
clear, oxygen rich waters that promote growth of plankton and sea grasses and promote fish
oxygen depleted zone
sedimentation in algae over growth reduced sunlight, kills beneficial sea grasses, uses up oxygen, and degrades habitats