Chapter 15
Water Management
The water issue
Water in its liquid from is the material that makes life possible on Earth. All living organisms are
composed of cells that contain at least 60 percent water. Furthermore, their metabolic activities take place
in water solution.Organisms can exist only where they have access to adequate supplies of water.
The hydrologic cycle
All water is locked into a constant recycling process called the hydrologic cycle. Two important processes
involved in the cycle are the evaporation and condensation of water.
Evaporation involves adding energy to molecules of liquid so that it becomes a gas in which the
molecules are farther apart.
Condensation is the reverse process in which molecules of a gas give up energy, get closer together,
and become a liquid.
Human influences on the hydrologic cycle
Human activities can significantly impact evaporation, runoff, and infiltration. When water is used for
cooling in power plants or to irrigate crops, the rate of evaporation is increased
A major concern in urban areas is providing ways to carry storm water away rapidly. Water
withdrawals are measurements of amount of water taken from a source. Water that is incorporated into a
product or lost to the atmosphere through evaporation or evapotranspiration cannot be reuse in the same
geographic area and is said to be consumed.
Kinds of water use
- Domestic use of water
- Agricultural use of water
- Industrial use of water
- In-Stream use of water
Kind and source of water pollution
Water pollution occurs when something enters water that changes the natural ecosystem or
interferes with water use by segments of society.
Dissolved organic matter is a significant water pollution problem because it decays in the water.
The amount of oxygen required to decay certain amount of organic matter is called the biochemical
oxygen demand. If too much organic matter is added to the water, all of the available oxygen will be used
up. Anaerobic respiration produces chemicals that have a foul odor.
Effect of organic waste on dissolved oxygen
When a source of pollution can be readily identified because ithas a definite source and place where it
enters the water, it is said to come from a point source. Diffuse pollutants, such as from agricultural land
and urban paved surfurban paved surfaces , acid rain and runoff, aye said to come from nonpoint sources
and are much more difficult to identify and control.
-be aware that many chemicals commonly used around the home are toxic
-buy chemical only in the amount you expect to use, and apply them only as directed.
-take unwanted household chemicals to hazardous waste collection centers.
-Never pour unwanted chemicals on the ground.
-Used water-based products whenever possible
Municipal water pollution
Manicipalities arw faced with the double-edged problem of providing suitable drinking water and
disposing of wastes. Wastes from homes consist primary of organic matter from garbage, food
preparation. Cleaning of clothes and dishes, and human wastes. Facal coliform bacteria are also present in
the wastes of other warm - blood animals
Agricultural water pollution
Agricultural activities are a primary cause of a water pollution problems. One of the largest waterpollution
problem is agricultural runoff for large expanses of open field.
Industrial water pollution. Factories and industrial complexes frequently dispose of some or all of their
into municipal sewage systems. A special sources of industrial water pollution is mining.
Thermal pollution : many industries use water for cooling, thermal pollution can be a problem. Thermal
pollution occurs when an industry removes water from a souce
Marine oil pollution : has many sources. One source is accidents, such as oil -drilling blowouts or oil
tanker accidents.
Groundwater pollution : make agricultural products, underground storage tanks, landfills, septic tank,
surface impoundments.
Water-use planning issue
Water diversion is the physicalprocess of transferring water from one area to another, the aqueducts of
ancient Rome are early example of water diversion. 1. Developing facilities to store surface water and
pump water into aquifers. 2. Developing wetland to treat municipal and agricultural runoff. 3. Using clean
wastwwater to recharge aquifers. 4. Reducing the amount of water lost through levees
Wastewater treatment : because water must be clean before it is released, most companies and
municipalities in the developed world maintain waste water treatment facilities.
Salinization : another water-use problem results from salinization, an increase in a salinity caused by
growing salt concentrations in soil ,Groundwater mining means that water is removed from aquifer faster
than it is replaced. It is common in area of the western USA., and throughout the world.
Preserving scenic water areas and wildlife habitats : the way in which the land adjacent to the water is
used must be consistent with preserving these scenic areas.
Chapter 16
Global Pollution and climate changes
Atmospheric layers
The atmosphere is composed of layers and composed of 78.1 percent nitrogen, 20.9 percent oxygen, and a number of
other gases such as argon, carbon dioxide, methane, and water vapor that total about 1 percent
Pollution of the atmosphere is any addition of matter or energy that degrades the environment for humans and other
organism. Bacause human action are the major cause of pollution we can do something to prevent it.
Categories of air pollutants
-
Carbon Monoxide
Particulate Matter
Sulfur Dioxide
Nitrogen Dioxide
Lead
The Atmosphere
The description of the Earth's Atmosphere is now in its own section: Atmosphere
Air Pollution
Primary air pollutants : pollutants emitted directly
Secondary air pollutants : pollutants created from reactions between primary air pollutants
Criteria air pollutants
6 pollutants regulated by the US Environmental Protection Agency (USEPA)
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carbon monoxide
particulate matter
sulfur dioxide
nitrogen dioxide
ozone
lead
Sulfur Dioxide and Acid Rain
Sulfur Dioxide Sulfur is oxidized to sulfur dioxide:
S + O2 → SO2
This can then be combined with water in the atmosphere to form sulfur dioxide:
2SO2 + O2 + 2H2O → H2SO4
Source:
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burning of sulfur-containing compounds including coal and oil
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smelting of metal ores
Cu2S + O2 → 2Cu + SO2 (metal ore)
Direct Effect
Absorbed by moist respiratory tissue causing restriction of airway especialy severe in people with asthma
Environmental Effect
Acid Deposition
The fallout of sulfuric acid either in rain or as dry particles is called acid deposition or, more commonly,
acid rain.
Effects: Destruction of concrete and stone structures
The sulfuric acid converts calcium carbonate to calcium sulfate which is more soluble: CaCO3 + H2SO4
Acid rain events on a stone monument Acidification of forests, rivers, and lakes Some lakes have natural
buffering, but many do not. Acidified water causes death of fish and other organisms, due to both the
lower pH directly and the leaching of metal, especially aluminum. It also causes damage to trees and other
plants. Acid rain damage on woodlands in Czech Republic
Nitrogen dioxide, ozone, and smog
Nitrogen Dioxide
Nitric oxide (NO) and nitrogen dioxide (NO2) are formed from high temperature combustion.
low temperature combustion: CH4 + O2 + N2 → CO2 + H2O + N2
high temperature combustion: CH4 + O2 + N2 → CO2 + H2O + NO
Nitric oxide and nitrogen dioxide are together called NOx (read as nox).
Health Effects:
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lung irritation
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increases susceptibility to lung disease
The flask contains nitrogen dioxide. It is this that gives the characteristic brownish color to smog
Ozone
Nitrogen dioxide reacts with sunlight to form nitric oxide and atomic oxygen. This oxygen reacts quickly
with molecular oxygen (O2) to form ozone. Ozone can then react with nitric oxide to regenerate nitrogen
dioxide.
NO2 + hν → NO + O
O + O2 → O3
O3 + NO → NO2 + O2
Note The ozone formed here is tropospheric ozone ("bad ozone"), not to be confused with stratospheric
ozone ("good ozone")
Health Effects:
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lung problems
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eye irritation
Environment Effects:
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damage to plants and trees
Ozone damage to plants. The top row shows normal plants, the bottom row show plants exposed to ozone.
Photochemical Smog
Tropospheric ozone reacts with organic chemicals to produce photochemical smog.
Smog is a toxic soup of NOx, ozone, peroxyacyl nitrates (PANs), aldehydes, and other organic chemicals.
Smog in Kuala Lumpur, Malaysia
Thermal inversions
Under certain conditions a layer of warm air can occur above cold air. This causes any pollutants to be
trapped and not dispersed.
Smoke rising in Lochcarron, Scotland is stopped by an overlying layer of warmer air
Winter smoke in Shanghai
A good animation of thermal inversion can be found here.
Particulate matter (PM) and Aerosols
Particulate Matter
Small solid and liquid particles which remain suspended in the atmosphere.
burning field producing particulate matter (smoke)
Sizes are up to 10 micrometers in diameter.
Sources:
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dust from construction, agriculture, and roads
forest fires
burning of solid and liquids -- especially from coal, wood, and diesel fuel
clearing of land for agriculture
Effects:
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The small particles can get trapped in the lining of the lung causing irritation,
inflammation, or cancer
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Inflammation
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Silicosis (silica dust)
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Black Lung disease (coal dust)
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Cancer
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Asbestos
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Polynuclear aromatic hydrocarbons (PAH)
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Tar from incomplete combustion and tobacco smoke
Asbestos micrograph showing the fibers
Toxic air pollutants
Carbon Monoxide (CO)
Car exhaust contains carbon monoxide (note CO is colorless, the white color is steam)
Source: incomplete burning of organic materials
complete combustion: CH4 + 2O2 → CO2 + 2H2O
incomplete combustion: CH4 + 1.5O2 → CO + 2H2O
Effects: binds with hemoglobin to form carboxyhemoglobin. This carboxyhemoglobin cannot transfer
oxygen to the cells.
Lead
Sources:
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paint
smelters
batteries
leaded gasoline
Effects:
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memory loss
learning difficulties
nervous system damage
damage to bones and kidneys
accumulative poison
Mercury
Mercury amalgam from small-scale gold mining. This will be heated to evaporate the mercury
Sources:
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burning of coal
small-scale gold mining
Effects:
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mental effects ("mad-hatter's" disease)
kidney disease
Volatile Organic Compounds (VOC's)
Definition: Organic compounds which rapidly evaporate.
Examples:
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benzene
acetone
solvents
formaladehyde (from building materials)
Effects: varies widely depending on substance
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eye, nose, and throat irritation
dizziness and headaches
damage to liver, kidney, and nervous system
actual toxicity varies widely
Indoor Air Pollution
Indoor air pollution is air pollutants found in your home, office, etc.
Examples:
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formaldehdye
chlorinated solvents
pesticides
tobacco smoke
radon
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Naturally radioactive gas. A decay product of radium (which is a decay product of
uranium). Uranium and radium can be found naturally in some rocks especially granite.
Radon can then enter houses built on such rocks.
Ozone Depletion
As stated above, the stratosphere contains a layer of ozone which protects the Earth from dangerous
ultraviolet radiation.
Chlorinated and brominated hydrocarbons can travel unreacted up to the stratosphere. The most important
of these are the chlorofluorocarbons (CFC's).
CCl3F + hν → CCl2F + Cl
This free chlorine then reacts with the ozone.
Cl + O3 → ClO + O2
This depletes the amount of ozone present.
These ozone depleting chemicals include:
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chlorofluorocarbons (CFC's)
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hydrochlorofluorocarbons (HCFC's)
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halons (bromochloroflurocarbons)
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methyl bromide
Montreal Protocol
In the 1980's, it was found the ozone layer was thinning. In 1987 a treaty called the Montreal Protocol was
signed.
It bans the use of ozone depleting chemicals. This has stabilized the ozone layer, though it will take many
years for the ozone layer to return to previous levels
Global Warming
Recent Climate Change The global temperature of the Earth has increased over the last century. Current
temperatures are 0.6 °C over the 1950-1980 average. All objects emit heat in the form of infrared (IR)
radiation. Gases in the atmosphere absorb the IR radiation from the Earth and reradiate it back to the
surface. This regulates the temperature. The natural greenhouse effect allows life to survive on Earth. But
problems occur when humans cause additional greenhouse effects.
Major human-generated greenhouse gases [1]:
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Carbon dioxide 76% of all greenhouse gas emissions
Methane 16%
Nitrous Oxide 8%
F-gases (see below) 1%
Carbon Dioxide
Carbon dioxide is by far the largest cause of global warming.
Largest sources of carbon dioxide:
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Burning of carbon-based fuels
Deforestation and burning grasslands for crop production
Methane
Methane is at lower concentrations, but has a stronger greenhouse effect.
Largest sources of methane:
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Agriculture,
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Cattle and other ruminants
Manure
Rice farming
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Nitrous Oxide
Nitrous Oxide (N20) is at low concentrations and has a strong greenhouse effect.
Largest sources:
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Natural denitrification in soils
Breakdown of fertilizers
Fluorinated Gases
Fluorinated gases (F-gases) which contribute to climate change include:
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Hydrofluorocarbons (HFC's) - used as substitutes for CFC's and HCFC's (HFC's do not
destroy the ozone)
Perfluorocarbons (PFC's) - used in electronics and other industries
Sulfur Hexaflouride (SF6) - used in high-voltage switches
Impacts of Global Warming
Changing of the weather. Global warming will cause shift in climate .An animation of how the Earth's
climate would change can be found here Generally, more hot days and fewer cool days. Tropics will get
less precipitation. Polar regions will get more precipitation.
Temperate regions will shift no
Sea level rise
The melting of the ice sheets and glaciers causes the amount of seawater to increase. Also heating water
causes it to expand. Models estimate that sea levels will rise 0.18 - 0.59 m. 10 percent of world's
population lives less than 10 m above sea level. Some island countries may no longer exist.
Wildlife
Global warming can also affect wildlife. It can affect their distribution. Some species have already
migrated towards the poles. This is a especially a threat to endangered species.
Permafrost melting
Permafrost is soil which remains frozen all year. Melting of permafrost is a feedback mechanism. It
releases methane, which increases global warming, which in turn causes more permafrost melting creating
a loop.
Ocean Acidification
This effect is due to the carbon dioxide directly and not temperature change. Carbon dioxide dissolves in
the ocean to create acid conditions.
This in turn has an effect on marine organisms. Acidic conditions increase the solubility of calcium
carbonate in shells of shellfish, coral, etc.
Mitigation
Reducing the amount of carbon dioxide
Methods of mitigation
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energy conservation
renewable energy sources
changing transport
carbon tax - taxing companies for each ton of carbon dioxide they produce
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reforestation
carbon sequestering ? - capturing CO2 and then pumping it underground
note that we are still producing carbon dioxide, but then burying it underground
the technology is untested. What happens if leaks occur and will changing acidity cause
problems?
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geoengineering - mega projects to reduce effects of global warming
examples: setting huge mirrors in outer space, adding huge quantities of iron filings to the ocean,
injecting aerosols of sulfur dioxide into the stratosphere
problems: hugely expensive, most are not technically feasible with today's technology, may have
undetermined consequences, and questions about governance
Adaptation
Measures to reduce the effects of global warming
Examples
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Building sea walls
Changing crop types
Generating a fund to help low income countries (the most talked about adaptation
measure)
Chapter 17
Solid waste management and disposal
1.Municipal solid waste landfill is typically constructed above an impermeable clay layer this is lined
with an impermeable membrane and includes mechanisms for dealing with liquid and gas materials
generated.
Methods of wastes disposal
Landfills have historically been the primary Method of waste disposal because this method is the cheapest
and most convenient, and the threat of groundwater contamination was not initially recognized.
Advantage
- Cheapest and the most convenient.
-Can use methane to generate electricity
Disadvantage
- Groundwater contamination
2.Incineration is the process of burning waste in the incinerator. Most incinerators can produce
electricity.
Mass burn is the technology to burn unprocessed Municipal Solid Waste
Advantage
- Reduce Municipal Solid Waste(90% by volume and 75% by weight).
- Electricity
Disadvantage
- More costly
- Air Quality and the toxicity
- Disposal of the ash.
3. Producing mulch and compost
Mulch is organic material that is used to cover the soil.
Composting is using natural decomposition to transform organic material into compost(humus-like
material)
Mulch for example Branches, Bark, and other organic materials are chopped into smaller pieces
Advantage
- Fertilizer
- Can be done at home
4. Source Reduction
is the method of designing, manufacturing, purchasing, and using in the way
to reduce the amount of waste and toxicity. Such as reducing the use of packaging, careful manufacturing,
purchasing necessary amount reuse etc.
Advantage
- Saving natural resource
- Reduce the toxicity
- Reduce cost
5. Recycling is one of the best environmental success stories of the late twentieth century.
Advantage
- Resource conservation
- Pollution reduction
- Energy saving
- Job creation
- Reduced need for landfills and incinerators.
Disadvantage
- Different plastics cannot be recycled together