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CHAPTER 11-16
ENVIRONMENTAL SCIENCE 15th Edition
© 2016 Congage Learning. All Rights Reserved.
Importance and Availability of Water
• Earth as a watery world – 71%
• Freshwater availability – 0.024%
– Groundwater
– Lakes
– Rivers
– Streams
• Globally, we have plenty of freshwater, but freshwater is not evenly distributed over the earth surface.
• We pollute and overuse it faster than natural processes can replenish it.
• Water access is a global health, economic and environmental issue.
• Groundwater infiltrates downward through spaces in soil and rocks
–Zone of saturation: underground areas of soil/rock where freshwater fills spaces between particles
–Water table: the top of the groundwater zone; fluctuates up and down depending on weather, and removal/replenishment rates
• Aquifer: underground body of rock that absorbs and holds flowing water
Freshwater Resources
• Surface water: the fresh water from rain
and melted snow stored at the surface
– Annually, 34% of the world’s reliable surface runoff is used
• 70% goes to irrigate crops and raise livestock, 20% is used by industry, and 10% is used by cities for drinking, cooking, etc.
• Indirect and virtual water: water used to produce food and other products – this is a large part of our water footprint
Freshwater Resources
Freshwater Shortages• Due to
– Dry climate
– Drought
– Too many people
– Wasting water
– using water faster than it can be replenished
• 1 of 9 people – no regular access to clean water
• Potential international conflicts over water
Increasing Freshwater Supplies
• Withdrawing groundwater
• Dams and reservoirs
• Transporting surface water
• Desalination
• Water conservation
Increasing Freshwater Supplies
• Withdrawing groundwater
• Dams and reservoirs
• Transporting surface water
• Desalination
• Water conservation
Increasing Freshwater Supplies
• Withdrawing groundwater
• Dams and reservoirs
• Transporting surface water
• Desalination
• Water conservation
Increasing Freshwater Supplies
• Withdrawing groundwater
• Dams and reservoirs
• Transporting surface water
• Desalination
• Water conservationDesalination: removing salt from sea water
Increasing Freshwater Supplies
• Withdrawing groundwater
• Dams and reservoirs
• Transporting surface water
• Desalination
• Water
conservation
Reducing Water Waste • Benefits of water conservation• Worldwide – 65-70% loss
– Evaporation, leaks– Can be reduced to 15%
• Increase the cost of water use– End subsidies for wasteful water use– Provide subsidies for efficient water use
• Improve irrigation efficiency– Center pivot– Low-pressure sprinkler– Precision sprinklers– Drip irrigation
• Use less in homes and businesses
Ways To Further Reduce Irrigation Water Loss
Fig. 11-17, p. 253
Solutions
Waste less water and subsidize
water conservation
Do not deplete aquifers
Preserve water quality
Protect forests, wetlands,
mountain glaciers, watersheds,
and other natural systems that
store and release water
Get agreements among regions
and countries sharing surface
water resources
Raise water prices
Slow population growth
Sustainable Water Use
Water Pollution & Sources• In Streams/lakes/reservoirs/groundwater
– Water pollution: water quality changes that harm living organisms or make water unfit for drinking/ irrigation/recreation
• Point sources
– Discharge at specific locations
– Easier to identify, monitor, regulate
• Nonpoint sources
– Broad, diffuse areas
– Runoff of chemicals, sediment, Agriculture
– Control is difficult and expensive
• Flowing streams and rivers use a combination of dilution and bacterial biodegradation to naturally eliminate waste.
–Does not work when overloaded with pollutants (historically from industrial waste water discharge) or when flow is reduced by drought, damming, or diversion
Stream and River Pollution
Lake Pollution• Dilution less effective than with
streams
–Stratification (thermal changes in deep lakes)
– Low flow rates
• Lakes are more vulnerable than streams
• Eutrophication – natural aging process
• OligotrophicStratification: arrange in
separate layer
Groundwater Pollution • Groundwater cannot cleanse itself of
degradable wastes as quickly as flowing surface water
• Pollution sources – from sewers, storage
• Slow flow, dilution, dispersion
• Low dissolved oxygen
• Fewer bacteria
• Cooler temperatures
• Long time scale for natural cleansing– Degradable wastes – organic matter
– Slowly degradable wastes – DDT
– Nondegradable wastes – lead, arsenic
• Protecting groundwater – prevention is best and least expensive
Ocean Pollution• Coastal areas – highly productive
ecosystems
– Occupied by 40% of population
– Coastal populations will double by 2050
– About 80% marine pollution originates on land
• Ocean dumping (controversies)
• Algal blooms
• Effect of oil pollution
• Volatile organic hydrocarbons
– Kill larvae
– Destroy natural insulation and buoyancy of birds and mammals
• Heavy oil
– Sinks and kills bottom organisms
– Coral reefs die
Larvae: insect/animal (such as frog)
that has left its egg but not
completely developed
Insulation: cover something to stop
heat
Heavy oil: oil with density heavier
than water
OCEAN DUMPING
Sewage Treatment Systems
• Rural and suburban areas – septic tanks
• Urban areas – Waterborne wastes from homes, businesses, and storm runoff flow through pipes to sewage treatment plants
–Primary sewage treatment – physical process
–Secondary sewage treatment –biological process
–Chlorination – disinfection
Chlorination: adding chlorine in water treatment to kill bacteria (disinfection)
Disposed of in
landfill or ocean or
applied to cropland,
pasture, or rangeland
Sludge drying bed
SludgeActivated sludge
Secondary
Raw sewage
from sewers
Air pump
(kills bacteria)
To river,
lake,
or ocean
Sludge digester
Chlorine
disinfection tankSettling tankAeration tankSettling tankBar screen Grit chamber
Primary
Fig. 11-28, p. 268
Sludge: semisolid
Grit – dense material
like sand, glass etc
In aeration tank: bacteria degrade
the waste and get activated
sludge (biological sludge)
Primary settling tank:
remove suspended solids
by gravity
Preventing Nonpoint Source Pollution
• Mostly agricultural waste
• Use vegetation to reduce soil erosion
• Use slow release fertilizer – and no fertilizer on steeply sloped land
• Use plant buffer zones around fields, animal feedlots and nearby surface water
• Keep feedlots away from slopes, surface water, and flood zones
• Integrated pest management
• Encourage organic farming methodsErosion (n), erode (v): slowly reduce/destroy
About 82% of the
commercial energy
consumed in the world
comes from
nonrenewable energy
resources—
76% from fossil fuels
(oil, natural gas, and
coal) and 6% from
nuclear power
Major sources of Energy
Fossil fuel
is a general term for buried combustible geologic
deposits of organic materials, formed from decayed
plants and animals that have been converted to
• crude oil
• coal
• natural gas
• heavy oils
Fossil fuels are currently abundant and relatively
inexpensive, but using them causes air and water
pollution, degrades large areas of land, and
releases greenhouse gases to the atmosphere.
Oil Sand and Oil Shale
• Oil sand (tar sand)
– Bitumen
• Shale Oil
– Kerogen
Coal (solid fossil fuel) Is a Plentiful
But Dirty Fuel (1)
• Used in electricity production
• World’s most abundant fossil fuel
• U.S. reserves should last about 250 years
Increasing moisture content Increasing heat and carbon content
Peat
(not a coal)
Lignite
(brown coal)Bituminous
(soft coal)
Anthracite
(hard coal)
Heat Heat Heat
Pressure Pressure Pressure
Partially decayed plant
matter in swamps and
bogs; low heat content
Low heat content; low
sulfur content; limited
supplies in most areas
Extensively used as a fuel
because of its high heat
content and large supplies;
normally has a high sulfur
content
Highly desirable fuel
because of its high heat
content and low sulfur
content; supplies are
limited in most areas
Coal Is a Plentiful
But Dirty Fuel (2)
• Sulfur and particulate pollutants
• Mercury and radioactive pollutants
• Heavy carbon dioxide emissions
• Pollution control and environmental costs
10%
286%Coal-fired electricity
150%Synthetic oil and
gas producedfrom coal
Coal 100%
Oil 86%
Natural gas 58%
92%Tar sand
Nuclear power fuel cycle
Geothermal
17%
Fig. 13-11, p. 306
CO2 emissions per
unit of electrical
energy produced
for various energy
resources
Fig. 13-17, p. 313
Conventional Nuclear Fuel Cycle
Cannot compete
economically without huge
government subsidies
Low net energy yield
High environmental impact
(with major accidents)
Environmental costs not
included in market price
Risk of catastrophic accidents
No widely acceptable solution
for long-term storage of
radioactive wastes
Subject to terrorist attacks
Spreads knowledge and
technology for building
nuclear weapons
Large fuel supply
Low environmental
impact (without
accidents)
Emits 1/6 as much CO2
as coal
Moderate land disruption
and water pollution
(without accidents)
Moderate land use
Low risk of accidents
because of multiple
safety systems (except for
Chernobyl-type reactors)
Trade-Offs
DisadvantagesAdvantages
Renewable Energy
• Sustainability mostly depends on
solar energy
– Direct form: from the sun
• Indirect forms
– Wind
– Moving water
– Biomass
– Geothermal
Using Solar Energy to Heat
Buildings and Water
• Passive solar heating system
• Active solar heating system
PASSIVE
Summer
sun
Winter
sun
Vent allows
hot air to
escape in
summer
Superwindow
Superwindow
Stone floor and wall for heat storage
Heavy
insulation
Fig. 13-25, p. 325
Solar thermal systems
Solar thermal plant
Solar cookers
Boron-
enriched
silicon
Phosphorus-
enriched silicon
Junction
Single solar cellSolar-cell roof
Roof options
Fig. 13-29, p. 328
Panels of
solar cells
Solar shingles
Producing Electricity from
Flowing Water
• Hydropower
– Leading renewable energy source
– Much unused capacity
• Dams and reservoirs
– Turbines generate electricity
– Eventually fill with silt
• Micro-hydro generators
Producing Electricity from Wind
• Indirect form of solar energy
• World’s second fastest-growing
source of energy
• Vast potential
– Land
– Offshore
Energy from Burning Biomass
• Biomass
– Wood
– Agricultural waste
– Plantations
– Charcoal
– Animal manure
• Common in developing countries
• Carbon dioxide increase in atmosphere
Converting Plant Matter to
Liquid Biofuel
• Biofuels
– Ethanol and biodiesel
– Crops can be grown in most countries
– No net increase in carbon dioxide
emissions
– Available now
• Sustainability
Energy by Tapping the Earth’s
Internal Heat
13-4 Why Is Energy Efficiency
an Important Energy Source?
We waste
huge
amounts of
energy.
Ex. inefficiency of incandescent
lights, furnaces, industrial
motors, coal and nuclear power
plants, motor vehicles, other
devices and badly designed
buildings.
Saving Energy and Money in
Industry
• Cogeneration/Combined Heat and
Power (CHP) systems
• Recycling
• Energy-saving electric motors
• Fluorescent lighting
• Smart grid electricity
(the steam produced in generating electricity in a CHP system can be used
to heat the plant or other nearby buildings, rather than released into the
environment and wasted.)
Hybrid and Fuel-Cell Cars
Saving Energy and Money in
New Buildings
• Green architecture
• Solar cells, fuel cells, eco-roofs,
recycled materials
• Super insulation
• Straw bale houses
Hazard = something that is dangerous and likely
to cause damage
An environmental hazard is any condition,
process, or state adversely affecting the
environment. Environmental hazards manifest as
physical or chemical pollution in air, water, and
soils. Environmental hazards can cause
widespread harm to humans and the physical
environment.Ex. Lead, PCBs, Asbestos, BPA
Major Types of Hazards
• Biological
• Chemical
• Physical ex. fire, earthquakes, volcanic eruptions, floods, and
storms.
• Cultural ex. unsafe working conditions, unsafe highways, criminal
assault, and poverty
• Lifestyle ex. smoking, eating too much, drinking too much alcohol,
and having unsafe sex
14-2 What Types of Biological
Hazards Do We Face?
• Concept 14-2 The most serious
infectious diseases are flu, AIDS,
tuberculosis, diarrheal diseases, and
malaria.
• Nontransmissible diseases
• Transmissible (infectious) disease
– Pathogens
• Epidemic*
• Pandemic**
* A large-scale outbreak of an
infectious disease in an area or
country.
** A global epidemic
Humans
Fetus and babies
Other humans
Water AirInsectsWild animalsLivestockPets Food
Stepped Art
Fig. 14-4, p. 348Pathways for infectious disease in humans.
14-3 What Types of Chemical
Hazards Do We Face?• Concept 14-3 There is growing concern
about chemicals that can cause cancer
and birth defects and disrupt the human
immune, nervous, and endocrine systems.
• Toxic chemicals
• Carcinogens
• Mutagens
• Teratogens (are chemicals that cause harm or birth
defects to a fetus or embryo)
• Some chemicals such as As, methyl-Hg, and
dioxins can weaken the human immune system
and leave the body vulnerable to attacks by
allergens and infectious bacteria, viruses, and
protozoa.
• PCBs, Pb, methyl-Hg, As, and pesticide can
harm the human nervous system (brain, spinal
cord, and peripheral nerves) and cause
behavioral changes, reduction of learning
disabilities, retardation, attention deficit disorder,
paralysis, and death.
Chemical Hazards
• Low exposure of BPA causes a brain damage,
prostrate disease, breast cancer, early puberty,
reduced sperm count, impaired immune
function, type 2 diabetes, hyperactivity,
increased aggressiveness, impaired learning,
increased addiction to drugs such as
amphetamines, decreased sex drive in males.
Chemical Hazards
Potential pathways on
which toxic chemicals move through
the living and nonliving environment
The concentrations
of some potential
toxins (Hg) in the
environment
increase as they
pass through the
successive
trophic levels of
food chains and
webs.
Determining Chemical Safety
• Toxicology
• Toxicity is a measure of how harmful a substance is.
• Dose
The effects of a particular chemical can
also depend upon by several factors i.e.
• Water and fat soluble toxins
• Persistence
• Biological magnification
Type and Severity of Health
Damage
• Response – dose dependent
– Acute effect
– Chronic effect
Table 14-1, p. 357
Estimating Toxicity
• Test on live animals
• Dose-response curve
– Lethal dose
– Median lethal dose
(LD50)
• Extrapolation from
data
Protection against Harmful
Chemicals
• Pollution prevention
• Precautionary principle
• Ban of 12 Persistent organic
pollutants (POPs) or the dirty dozen (POPs can persist for long periods of time in the environment and
can accumulate and pass from one species to the next through the
food chain) Stockholm Convention
• Risk analysis (risk assessment)
• Comparative risk analysis
• Risk management
• Risk communication
• Poverty – the greatest risk (malnutrition,
increased susceptibility to normally nonfatal infectious diseases, and often-
fatal infectious diseases transmitted by unsafe drinking water)
another is lifestyles.
14-5 How Do We understand Risks and
How Can We Avoid the Worst of Them?
Fig. 14-3, p. 345
Outdoor Air Pollution
• What is air pollution?– The presence of one or more chemicals in the air (outdoor or
indoor) in sufficient quantity and duration to cause harm to us, other forms of life, and materials, or to alter climate.
• Stationary and mobile sources
• Primary pollutants– Emitted directly into the troposphere in a potentially harmful form.
– eg. CO, CO2, SO2, NO, NO2, HCs, SS
• Secondary pollutants– Some of the primary pollutants react with one another or basic
components in the air and form a new pollutants.
– e.g., SO3, HNO3, H2SO4, H2O2, O3, PANs* , NO3- and SO4
2- salt
*Peroxyacyl nitrates
Most NO3– and SO4
2– salts
Mobile
Sources Natural Stationary
Secondary Pollutants
Primary Pollutants
Most hydrocarbons
Most suspended particles
CO2CO
SO2
PANs
SO3
NO2NO
H2SO4HNO3
O3H2O2
Fig. 15-3, p. 371
Sources and types of air pollutants.
Industrial Smog (intense air pollution)
• Gray-air “smog” = smoke + fog
• Occur when we consumed too much coal and
heavy oil (contain sulfur impurities) in power
plants and factories in big cities. We were
exposed to industrial smog during winter.
• Industrial smog consists of:
Smoke + Sulfur dioxide mix with fog droplet
thick blanket of haze
Fig. 15-4, p. 373
Photochemical Smog• Brown-air smog occur in drier and sunny day
• Photochemical smog is a mixture of primary
NO+VOC react to sunlight form secondary
pollutants (O3 Peroxyacyl nitrates)
• Photochemical reaction = any chemical
reaction which is activated by light.
• Happen in big city with sunny, warm and dry
climate & a lots of motor vehicles.
Acid Deposition (Acid rain)
• Any form of precipitation (wet or dry)
with acidic component
• SO2 and NOX react with water and
from sulfuric and nitric acids
• Acid rain is a regional air pollution not
local air pollution
– Midwest coal-burning power plants
– Prevailing winds
Natural Factors That Reduce
Air Pollution
• Particles heavier than air
• Rain and snow
• Salty sea spray from oceans
• Winds (diluting with cleaner air)
• Chemical reactions For example, SO2 can
react with O2 in the atmosphere to form SO3, which
reacts with water vapor to form droplets of H2SO4 that
fall out of the atmosphere as acid precipitation.
Natural Factors That Increase
Air Pollution
• Urban buildings (block air circulation)
• Hills and mountains
• High temperatures (promote chem. reaction)
• VOC emissions from certain trees and
plants
• Grasshopper effect (north pole)
• Temperature inversions
Indoor Air Pollution
• Developing countries - indoor cooking and
heating, smoking – cause respiratory diseases
• Low ventilation, use of synthetic materials for
building and furnishing ,use of chemical
products, pesticides, and household care
products
• EPA – top cancer risk
• Major Indoor Air Pollutants:
– Tobacco smoke, Formaldehyde, Radon-222,
Very small particles
Fig. 15-8, p. 377
AsbestosSource: Pipe insulation, vinylceiling and floor tilesThreat: Lung disease, lung cancer
Carbon monoxideSource: Faulty furnaces,unvented gas stoves andkerosene heaters,woodstovesThreat: Headaches,drowsiness, irregularheartbeat, death
Methylene chlorideSource: Paint strippers and thinnersThreat: Nerve disorders, diabetes
Tobacco smokeSource: CigarettesThreat: Lung cancer, respiratoryailments, heart disease
Radon-222Source: Radioactive soiland rock surroundingfoundation, water supplyThreat: Lung cancer
Benzo-α-pyreneSource: Tobacco smoke,woodstovesThreat: Lung cancer
StyreneSource: Carpets,plastic productsThreat: Kidney andliver damage
FormaldehydeSource: Furniture stuffing,paneling, particleboard,foam insulationThreat: Irritation of eyes,throat, skin, and lungs;nausea; dizziness
TetrachloroethyleneSource: Dry-cleaningfluid fumes on clothesThreat: Nerve disorders,damage to liver andkidneys, possible cancer
Para-dichlorobenzeneSource: Air fresheners,mothball crystalsThreat: Cancer
ChloroformSource: Chlorine-treated water inhot showersPossible threat: Cancer
1,1,1-TrichloroethaneSource: Aerosol spraysThreat: Dizziness,irregular breathing
Nitrogen oxidesSource: Unvented gasstoves and keroseneheaters, woodstovesThreat: Irritated lungs,children's colds,headaches
ParticulatesSource: Pollen, petdander, dust mites,cooking smoke particlesThreat: Irritated lungs,asthma attacks, itchyeyes, runny nose,lung disease
Stepped Art
Using the Marketplace to
Reduce Air Pollution
• Emissions trading (cap and trade)
program (program designed to limit the
total level of emissions of certain
chemicals)
– Proponents – cheaper and more
efficient
– Critics – companies buy their way out
• Success depends on cap being
gradually lowered (reduce the ceiling )
Fig. 15-11, p. 380
Fig. 15-12, p. 381
Evidence to Support Global
Warming (1)
• Intergovernmental Panel on Climate
Change (IPCC)
• 2007 IPCC report
• Rise in average global surface
temperature
• 10 warmest years on record since
1970
Evidence to Support Global
Warming (2)
• Annual greenhouse gas emissions up
70% between 1970 and 2008
• Changes in glaciers, rainfall patterns,
hurricanes
• Sea level rise in this century 4–8
inches
Fig. 15-19, p. 385
Sept. 1979
Russia
Alaska (U.S.)
Canada
GreenlandNorthpole
*
Sept. 2008
Russia
Alaska (U.S.)
Canada
GreenlandNorthpole
*
CO2 Is the Major Culprit
• 1850: 285 ppm
• 2009: 388 ppm
• Over 450 ppm is
tipping point
• 350 ppm as
intermediate goal
Fig. 15-B, p. 387
Comparison of
measured changes
in the average
temperature of the
atmosphere at
the earth’s surface
between 1860
and 2007 and the
projected range
of temperature
increase during the
rest of this century.
Some Possible Effects of a Warmer World
• Increased deaths from heat and disease
• Disruption of food and water supplies
• Spread of tropical diseases to temperate areas
• Increased respiratory disease
• Increased water pollution from coastal flooding
Human Health
• Rising sea levels
• Flooding of low-lying islands and coastal cities
• Flooding of coastal estuaries, wetlands, and coral reefs
• Beach erosion
• Disruption of coastal fisheries
• Contamination of coastal aquifiers with salt water
Sea Level and Coastal Areas
• Changes in forest composition and locations
• Disappearance of some forests
• Increased fires from drying
• Loss of wildlife habitat and species
Forests
• Changes in water supply
• Decreased water quality
• Increased drought
• Increased flooding
Water Resources
• Shifts in food-growing areas
• Changes in crop yields
• Increased irrigation demands
• Increased pests, crop diseases, and weeds in warmer areas
Agriculture
• Extinction of some plant and animal species
• Loss of habitats
• Disruption of aquatic life
Biodiversity
• Prolonged heat waves and droughts
• Increased flooding
• More intense hurricanes, typhoons, tornadoes, and violent storms
Weather Extremes
• Increased deaths
• More environmental refugees
• Increased migration
Human
Population
Fig. 13.11, p. 311
Fig. 15-23, p. 393
Human Impact on
the Ozone Layer
• Location and purpose of the ozone
– Stratosphere & Blocks UV-A and UV-B
• UV threat to humans, animals, plants
• Natural process cause seasonal change
• Human activity caused a long-term
depletion by ODS (Ozone-depleting
substances) ex. chlorofluorocarbons
(CFCs), carbon tetrachloride
Reversing Ozone Depletion
• Stop producing ozone-depleting
chemicals
• Slow recovery
• Montreal Protocol
• Copenhagen Protocol
• International cooperation
Solid waste
means any garbage, refuse, sludge from
a wastewater treatment plant, water
supply treatment plant, or air pollution
control facility and other discarded
materials including solid, liquid, semi-
solid, or contained gaseous material.
Hazardous waste
is waste (solid, liquid, sludge, gas) that
has substantial or potential threats to
public health or the environment.
Wasting Resources
• Solid Waste
– Industrial solid waste
(Mining, Agriculture, Industry)
– Municipal solid waste
(Homes, Businesses)
Ex. food waste, vegetable and fruit
peels, recyclables waste (paper, plastic,
metals, glass), paints, pesticides, used
batteries, and medical waste
Wasting Resources (2)
• Hazardous or toxic waste
– Threatens human health or the environment
– Poisonous, Reactive, Corrosive, Flammable
Wasting Resources (3)
• Solid waste and hazardous waste
– Create air and water pollution, land
degradation
– About 3/4 is unnecessary resource
waste
16-2 How Should We Deal with
Solid Waste?
• Concept 16-2 A sustainable approach
to deal with solid waste is first to reduce
it, then to reuse or recycle it, and finally
to safely dispose of what is left.
1. Waste management “What do we do with solid
waste?”
2. Waste reduction “How can we avoid producing so
much solid waste?”
Integrated waste management
Reuse
• Reuse as a form of waste reduction
• Salvaging
• Yard sales, flea markets, secondhand
stores, auctions, newspaper ads,
Craigslist, e-bay
• Technology: rechargeable batteries
• Refillable containers and cloth bags
Recycling
• Change used material into new products.
• Paper, Glass, Aluminum, Steel, Plastics
• Primary (closed-loop) recycling-same
product
• Secondary recycling-different product
• Pre-consumer (internal) waste
• Postconsumer (external) waste
• Feasibility and marketing
Composting
• A form of recycle using decomposing
bacteria
• Household composting (small)
• Organic waste collection facilities (large)
• Successful large-scale composting
– Odor control
– Exclude toxic materials
Mixed vs Separate
Household Recycling
• Material recovery facilities (MRF)
– Can be expensive
• Source separation
– By households and
businesses
– Glass, paper, metals
plastics, compostable
16-4 Advantages and Disadvantages
of Burning or Burying Solid Waste?
• Concept 16-4 Technologies for burning
and burying solid wastes are well
developed, but burning contributes to
pollution and greenhouse gas emissions,
and buried wastes can eventually
contribute to air and water pollution and
land degradation.
Boiler
WetscrubberFurnace
Steam TurbineSmokestack
Electricity
Electrostaticprecipitator
Ash for treatment,
disposal in landfill, or
use as landfill cover
Fig. 16-9, p. 413
Burying Solid Wastes
• We can manage the solid waste by
landfill.
• Open dumps
• Sanitary landfills (solid wastes are spread
out in thin layers, compacted, and covered
daily with a fresh layer of clay or plastic
foam)
• Reduce leakage of leachates
16-5 How Should We Deal with
Hazardous Waste?
• Concept 16-5 A more sustainable
approach to hazardous waste is first to
produce less of it, then to reuse or recycle
it, then to convert it to less hazardous
materials, and finally to safely store what
is left.
Detoxifying Hazardous Waste
• Bioremediation
• Phytoremediation
• Incineration
• Plasma arc torch
Storing Hazardous Waste
• Widely used method in most countries
• Deep-well disposal
– Below aquifers in dry, porous rock
• Surface impoundments (ponds, pits, or
lagoons)
– 70% in U.S. have no liners
– 90% may threaten groundwater
• Secure landfills
Fig. 16-14, p. 417
Leak
detection
system
Groundwater
monitoring
well
Reactive
wastes
in drums
Plastic
double
liner
Water
table
Earth
Double leachate
collection system
Groundwater
Clay
cap
Impervious
clay cap
Plastic cover
impervious
clay
Bulk
waste
Gas
vent
Topsoil
Earth
Sand
Fig. 16-16, p. 418
Achieving a Low-Waste Society
• Grassroots action
• Environmental justice
• International treaties
– Basel Convention
– Persistent organic pollutants (POPs)
• Dirty dozen ban (Stockholm Convention)