Botkin Environmental Science Earth as Living Planet 8th txtbk

Reexamining Themes and Issues 425
Wastewater treatment at conventional treatment plants
includes primary, secondary, and, occasionally, advanced
treatment. In some locations, natural ecosystems,
such as wetlands and soils, are being used as part
of the treatment process.
Water reuse is the norm for millions of people living
along rivers where sewage treatment plants discharge
treated wastewater back into the river. People who withdraw
river water downstream are reusing some of the
treated wastewater.
Industrial reuse of water is the norm for many factories.
Deliberate use of treated wastewater for irrigating agricultural
lands, parks, golf courses, and the like is growing
rapidly as demand for water increases.
Cleanup and treatment of both surface water and
groundwater pollution are expensive and may not be
completely successful. Furthermore, environmental
damage may result before a pollution problem i
s identified and treated. Therefore, we should continue
to focus on preventing pollutants from entering
water, which is a goal of much water-quality
legislation.
REEXAMINING THEMES AND ISSUES
Human
Population
Sustainability
Global
Perspective
Urban World
We state in this chapter that the number one water-pollution problem in
the world today is the lack of disease-free drinking water. This problem is
likely to get worse in the future as the number of people, particularly in
developing countries, continues to increase. As population increases, so
does the possibility of continued water pollution from a variety of sources
relating to agricultural, industrial, and urban activities.
Any human activity that leads to water pollution—such as the building
of pig farms and their waste facilities on floodplains—is antithetical to
sustainability. Groundwater is fairly easy to pollute and, once degraded,
may remain polluted for a long time. Therefore, if we wish to leave a fair
share of groundwater resources to future generations, we must ensure
that these resources are not polluted, degraded, or made unacceptable for
use by people and other living organisms.
Several aspects of water pollution have global implications. For example,
some pollutants may enter the atmosphere and be transported long
distances around the globe, where they may be deposited and degrade
water quality. Examples include radioactive fallout from nuclear reactor
accidents or experimental detonation of nuclear devices. Waterborne pollutants
from rivers and streams may enter the ocean and circulate with
marine waters around the ocean basins of the world.
Urban areas are centers of activities that may result in serious water pollution.
A broad range of chemicals and disease-causing organisms are
present in large urban areas and may enter surface waters and groundwaters.
An example is bacterial contamination of coastal waters, resulting
in beach closures. Many large cities have grown along the banks of
streams and rivers, and the water quality of those streams and rivers is
often degraded as a result. There are positive signs that some U.S. cities
are viewing their rivers as valuable resources, with a focus on environmental
and economic renewal. Thus, rivers flowing through some cities
are designated as greenbelts, with parks and trail systems along river corridors.
Examples include New York City; Cleveland, Ohio; San Antonio,
Texas; Corvallis, Oregon; and Sacramento and Los Angeles, California.