Environmental Engineering Reference
In-Depth Information
advantages and disadvantages of this method of dis-
posal. EPA studies found that 70% of these storage
basins in the United States have no liners, and as
many as 90% may threaten groundwater. According
to the EPA, all liners are likely to leak eventually and
can contaminate groundwater.
What Can You Do?
Hazardous Waste
• Use pesticides in the smallest amount possible.
x
• Use less harmful substances instead of commercial
chemicals for most household cleaners. For example,
use liquid ammonia to clean appliances and windows;
vinegar to polish metals, clean surfaces, and remove
stains and mildew; baking soda to clean household
utensils, deodorize, and remove stains; borax to remove
stains and mildew.
H OW W OULD Y OU V OTE ? Do the advantages of storing
hazardous waste in surface impoundments outweigh the dis-
advantages? Cast your vote online at http://biology.brookscole
.com/miller11.
Sometimes liquid and solid hazardous wastes are
put into drums or other containers and buried in care-
fully designed and monitored secure hazardous waste
landfills (Figure 17-19). Sweden buries its concentrated
hazardous wastes in underground vaults made of re-
inforced concrete. By contrast, in the United Kingdom
most hazardous wastes are mixed with household
garbage and stored in hundreds of conventional land-
fills throughout the country.
Hazardous wastes can also be stored in carefully
designed aboveground buildings —a good option in ar-
eas where the water table is close to the surface or ar-
eas that are above aquifers used for drinking water.
These structures are built to withstand storms and to
prevent the release of toxic gases. Leaks are monitored
and any leakage is collected and treated.
To most environmental scientists, the real solution
to the hazardous waste problem is to produce as little
as possible in the first place (Figure 17-14). Figure 17-20
lists some ways you can reduce your output of haz-
ardous waste into the environment.
• Do not dispose of pesticides, paints, solvents, oil,
antifreeze, or other products containing hazardous
chemicals by flushing them down the toilet, pouring
them down the drain, burying them, throwing them
into the garbage, or dumping them down storm drains.
Figure 17-20 Individuals matter: ways to reduce your input of
hazardous waste into the environment. Critical thinking: which
of the things in this list do you do or plan to do?
17-8
TOXIC METALS
Science Case Study: Lead
Lead is especially harmful to children and is still
used in leaded gasoline and household paints in
about 100 countries.
Because it is a chemical element, lead (Pb) does not
break down in the environment. This potent neuro-
toxin can harm the nervous system, especially in young
Topsoil
Plastic cover
Gas vent
Earth
Impervious clay cap
Bulk waste
Sand
Impervious
clay
Clay cap
Earth
Water
table
Leak
detection
system
Groundwater
Double leachate
collection system
Plastic
double
liner
Groundwater
monitering
well
Reactive
wastes
in drums
Solid and Hazardous Waste
Figure 17-19 Solutions: secure hazardous waste landfill.
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