Environmental Engineering Reference
In-Depth Information
reduce pesticide runoff. Farmers can control runoff
and infiltration of manure from animal feedlots by
planting buffers and locating feedlots and animal
waste sites away from steeply sloped land, surface wa-
ter, and flood zones.
Solutions
Coastal Water Pollution
Prevention
Cleanup
x
H OW W OULD Y OU V OTE ? Should we greatly increase
efforts to reduce water pollution from nonpoint sources even
though this could be quite costly? Cast your vote online at
http://biology.brookscole.com/miller11.
Reduce input of toxic
pollutants
Improve oil-spill
cleanup
capabilities
Separate sewage
and storm lines
Ban dumping of
wastes and sewage
by maritime and
cruise ships in
coastal waters
Sprinkle
nanoparticles
over an oil or
sewage spill to
dissolve the oil or
sewage without
creating harmful
by-products
(still under
development)
Politics: Laws for Reducing Water Pollution
from Point Sources
Most developed countries use laws to set water
pollution standards. In most developing countries,
such laws do not exist or are poorly enforced.
The Federal Water Pollution Control Act of 1972 (re-
named the Clean Water Act when it was amended in
1977) and the 1987 Water Quality Act form the basis
of U.S. efforts to control pollution of the country's
surface waters. The Clean Water Act sets standards
for allowed levels of key water pollutants and re-
quires polluters to get permits limiting how much of
various pollutants they can discharge into aquatic
systems.
The EPA is also experimenting with a discharge
trading policy that uses market forces to reduce water
pollution in the United States. Under this program, a
water pollution source is allowed to pollute at higher
levels than allowed in its permits if it buys credits from
permit holders with pollution levels below their al-
lowed levels.
Some environmentalists support discharge trad-
ing. But they warn that such a system is no better than
the caps set for total pollution levels in various areas,
and call for careful scrutiny of the cap levels. They also
warn that discharge trading could allow pollutants to
build up to dangerous levels in areas where credits are
bought. In addition, they call for gradually lowering
the caps to encourage prevention of water pollution
and development of better technology for controlling
water pollution, neither of which is a part of the cur-
rent EPA discharge trading system.
According to Sandra Postel, director of the Global
Water Policy Project, most cities in developing coun-
tries discharge 80-90% of their untreated sewage di-
rectly into rivers, streams, and lakes. These waters are
then used for drinking water, bathing, and washing
clothes.
Ban ocean dumping
of sludge and
hazardous dredged
material
Protect sensitive
areas from
development, oil
drilling, and oil
shipping
Require at least
secondary
treatment of
coastal sewage
Regulate coastal
development
Recycle used oil
Use wetlands,
solar-aquatic, or
other methods to
treat sewage
Require double hulls
for oil tankers
Figure 11-31 Solutions: methods for preventing and cleaning
up excessive pollution of coastal waters. Critical thinking: which
two of these solutions do you believe are the most important?
11-8 PREVENTING AND REDUCING
SURFACE WATER POLLUTION
Solutions: Reducing Surface Water Pollution
from Nonpoint Sources
The key to reducing nonpoint pollution—most of it
from agriculture—is to prevent it from reaching
bodies of surface water.
There are a number of ways to reduce nonpoint water
pollution, most of which comes from agriculture. Farm-
ers can reduce soil erosion by keeping cropland covered
with vegetation and by reforesting critical watersheds.
They can also reduce the amount of fertilizer that runs
off into surface waters and leaches into aquifers by us-
ing slow-release fertilizer, using none on steeply sloped
land, and planting buffer zones of vegetation between
cultivated fields and nearby surface water.
Applying pesticides only when needed and rely-
ing more on integrated pest management (p. 233) can
Science: Reducing Water Pollution
from Point Sources
Septic tanks and various levels of sewage treatment
can reduce point-source water pollution.
 
 
 
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