Environmental Engineering Reference
In-Depth Information
FIGURE 5.1 1952 loating oil and debris ire on the Cuyahoga River near Cleveland, Ohio. (From NOAA,
Available at http://oceanservice.noaa.gov/education/kits/pollution/02history.html.)
During the 1960s and 1970s, national concern with regard to the quality of the nation's waters
increased. During this period, Rachel Carson's (1962) Silent Spring was published and helped
launch a national environmental movement. Scientiic reports and articles were common, detailing
the pollution problems. Organizations such as the National Wildlife Federation, the Izaak Walton
League, and the National Audubon Society campaigned for strong federal water quality bills. On
April 22, 1970, approximately 20 million people participated in the irst Earth Day. Earth Day was
spearheaded by Wisconsin Senator Gaylord Nelson to draw attention to the environmental issues
plaguing the planet and human health and it continues to be celebrated each April 22.
The results of the national environmental movement included a series of strong federal environ-
mental laws, one of the most powerful of which was the 1972 Amendments to the Federal Water
Pollution Control Act, now popularly known as the CWA, by the 92nd U.S. Congress. The frame-
work of that act included (USEPA 2000c):
The establishment of the National Pollutant Discharge Elimination System (NPDES), a
program that requires that every point source discharger of pollutants obtains a permit and
meets all the applicable requirements speciied in the regulations issued under Sections
301 and 304 of the act. These permits are enforceable in both federal and state courts, with
substantial penalties for noncompliance.
The development of technology-based efluent limits, which serve as the minimum treat-
ment standards to be met by dischargers.
An ability to impose more stringent water quality-based efluent limits (WQBELS) where
technology-based limits are inadequate to meet state water quality standards or objectives.
The creation of a inancial assistance program to build and upgrade publicly owned treat-
ment works (POTWs).
Major water quality concerns at the time included the bacterial contamination of waters and low
dissolved oxygen (DO) concentrations resulting from high loads of organic materials, such as from
untreated wastewater. As bacteria degrade organic materials in waters that contain oxygen (oxic
waters), DO is consumed.
In 1968, approximately 39% of the people served by POTWs in the United States received less
than secondary treatment (raw and primary; USEPA 2000c). Primary treatment only removes loat-
ing and suspended solids, thereby removing only a fraction of the organic material impacting DO.
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