environmental science th edition

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





• Desalination

• Water conservationDesalination: removing salt from sea 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


– 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)

environmental science th edition

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