Welcome to:
Water Quality and Treatment
EH Program
Guang Jin
Introduce Yourself
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What makes you to choose this
course?
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What do you expect to get out from
this course?
I. Water Quality
A. A History of Water Quality
Source of water and changes in water
quality throughout history
Objectives

Students should be able to:
– Describe the source of water on Earth.
– Describe how water quality has changed
throughout history due to human actions
Source of Water
on Earth

About 3 billions years ago, the Earth cooled
enough for hydrogen and oxygen to combine
in the atmosphere to form water.

Torrential rains occurred for millions of years,
washing salts and other minerals into low
areas to form lakes, rivers and oceans.
Changes in water quality
throughout history

Physical, chemical, and biological
“contaminants” have always been
present in water in low concentrations.

Human activities have changed water
quality dramatically because of high
population and synthetic chemicals.
Changes in water quality
throughout history

Several major changes in the past few
hundred years have changed water
quality dramatically:
– changed in animal population
– changes in plant populations
– introduction of “persistent” and
biomagnified” synthetic chemicals, and
other human wastes.
Destruction of animal
populations
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Beavers once slowed rates of water runoff
and allowed percolation of water
Prairie dogs and other rodents allowed quick
recharge of groundwater through borrows.
Buffalo and other grazers created “wallows”
to create groundwater recharge zones
Freshwater mussels filtered water to improve
water quality
Changes in plant
population
Vast forests once captured water and
released it slowly into the environment
 Vast grassland prairies also slowed
movement of water through the
environment.
 Agricultural “monocultures”, plowing,
and damming of rivers created changes
in both plant and animal populations

Human-made Wastes
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Human designed synthetic organic chemicals
which are “persistent” in the environment.
Humans capture, use, contaminate, treat,
and release tremendous quantities of water.
These wastes contain organic chemicals
which can imbalance the natural ability of
water to clean itself (BOD, or Biochemical
Oxygen Demand)
Summary
While some water had always contained
organic and inorganic contaminants,
human population has increased them
significantly in the past few hundred
years.
 Introduction of “persistent” synthetic
compounds and other human wastes has
created imbalances in natural systems
designed to purify water.

B. Aqueducts and Reservoirs
A brief history of drinking water
treatment and protection
Objectives

Student should be able to:
– Describe the history of water sources,
treatment, and protection in the U.S. and
Europe.
Early water supplies:
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As early as 2500 B.C., the Sumerians brought
clean water from the mountains for irrigation
and drinking purposes.
Roman aqueduct systems are a model of
engineering efficiency (simple yet effective).
However, early Europeans had poor quality
waste treatment and water supplies.
Water, waste and disease
Early civilization knew that clean water
supplies were essential to good health.
 The relationship of human and animal
wastes to waterborne disease was not
firmly established until the late 1800’s. example of cholera(caused by Vibrio
cholera)
 Typhoid fever (caused by Salmonella
typhi) was a problem in the U.S.

Early water sources
in the U.S.
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Most early U.S. cities such as Boston, got
their drinking water from well, which rapidly
became polluted with waste.
Like Europe, early U.S. cities were subjected
to waterborne illness epidemics.
Cities which had relatively clean water
supplies, such as Philadelphia, were noticed
to have much lower illness rates.
Early water treatment
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Evidence of primary water treatment was
found in Egypt as early as 2000 B.C.
Pliny described the use of alum and lime for
water treatment in 77 A.D.
In Englande, use of alum for purifying
drinking water was common.
In Bolton, Englande in 1881, flocculation was
used to treat drinking water.
Early water treatment in
the U.S.
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In 1892, Poughkeepsie N. Y. whose water
source was the Hudson River, used sand
filtration for purifying drinking water.
In 1893, when Lawrence, MA, added water
filters, and death rate for typhoid fever fell
from 134 to 30 per 100,000.
Allen Hazen of Boston found in 1903 that
death rates for other illness also dropped.
Disinfection of water supplies
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The Union Stockyard company of Chicago
was sued by City of Chicago for poaching
municipal water.
The stockyard started using water from
sewage-polluted Bubbly Creek by adding first
copper sulfate, then chloride of lime.
Cattle first lost weight, then thrived, and use
of chlorine for disinfection was begun.
Summary
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The value of clean drinking water supplies
has been realized for thousands of years.
Physical (filtration, sedimentation) and
chemical (flocculation) treatment of polluted
water supplies was shown to dramatically
reduce the prevalence of waterborne illness.
Disinfection (chlorine) was the final step in
reducing waterborne illness.
C. Importance of water, its
unique properties, and its
distribution on Earth
Objectives
Students should be able to:
 List and describe unique characteristics
of water than make it essential for life.
 Discuss the unequal distribution of
available freshwater on the Earth and
the U.S.
Importance of Water
Most organisms are 60-65% water by
weight.
 Water is vital for agriculture,
manufacturing, climate, etc.
 Life could not exist without water.
 71% of the Earth is covered by water
 Water is the major feature of the Earth
seen from space.
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Unique properties of water
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Liquid over wide temperature range.
(BP = 100oC, FP = 0oC)
Temperature buffer
 Heat exchange (climate)
 Polar solvent
 Expand when it freezes.
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Distribution of world water
Distribution of water on Earth
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97% of water is in the oceans.
3% is freshwater
Only 0.003% is easily available as soil
moisture, usable groundwater, or in lakes,
rivers, and streams
Assume that all water on Earth is represented
by 100 liter (26 gal.)
– less than one gallon would represent al freshwater
– less than one teaspoonful would be readily
available freshwater
– Large portions of readily available freshwater are
polluted or inaccessible
The distribution of water on
Earth is unequal
Iceland has an abundance of water
from precipitation
 The Middle East has severe water
shortage
 The Northwest U.S. gets large amounts
of rainfall due to mountains.
 The southwest U.S. has severe water
deficiencies
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Summary
Water is essential to living things and is
chemically and physically unique.
 Quality water is extremely limited and is
unequally distributed in the United
States and on the Earth.
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D. The Hydrologic Cycle
Objectives
Student should be able to:
 Describe and/or diagram the hydrologic
cycle and distinguish its components.
 Discuss the importance of the
hydrologic cycle for purification of water
on Earth
The Hydrologic Cycle:

This is a global, natural system in place
for purification of water on Earth, and
has several key elements:
– Evaporation (Liquid to gas)
– Condensation (gas to liquid)
– Precipitation (rain, snow, sleet, etc.)
– Infiltration, percolation, runoff.
Evaporation
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Evaporation is conversion of liquid
water into water vapor.
– This process distills the water, leaving
contaminants behind.
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Evaportranspiration is evaporation of
water from leaves of plants and soils
– functions due to surface tension drawing
water from soil to roots and to leaves.
Condensation
Absolute humidity is the amount of
water that a volume of air can hold.
 Relative humidity is the amount of
water in air compared to the maximum
it could hold at a particular temperature
 The dew point is the temperature at
which moisture begins to condense
from the air.
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Precipitation
Moisture condenses on small particles
to form condensation nuclei.
 Droplets combine until gravity causes
them to fall to Earth (rain, snow, sleet).
 15 trillion liters of water (4 trillion
gallons) of water fall on the U.S. every
day.
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Infiltration, percolation, runoff
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About 66% of precipitation evaporates.
About 31% runs off land into lakes, rivers, etc. and
eventually, the ocean.
About 3% percolates through soils into groundwater.
Some water infiltrates into soils and remains as soil
moisture
The hydrologic cycle is powered by energy from the
sun and gravity.
– Solar energy evaporates water and forms water vapor.
– Winds and air movement transport the water vapor.
– Changing temperatures cause condensation and
precipitation.
How humans affect the
hydrologic cycle
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Humans affect the hydrologic cycle in
two major ways:
– By withdrawing huge amounts of
freshwater from well, lakes, streams, etc.
(this may lead to water depletion or
intrusion of salt water)
– By cleaning vegetation for agriculture,
mining, roads, etc. (decreases infiltration,
percolation, increases runoff).
Environmental factors that affect
water quality and availability
Climate - rain, snow, temperature, etc.
 Topography - hills, valleys, slopes, etc.
 Geology - soil, rock, minerals, etc.
 Geography - lakes, streams, cities, etc.
 Population - concentration of animals
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and plants.
 Water use - drinking, bathing, etc.
Summary
The hydrologic cycle is made up of several
components including evaporation,
condensation, and precipitation.
 The hydrologic cycle is a natural process
that helps to purify water on Earth.
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