Transcript water

Water Quality Notes
1
Topic: Water Quality Notes
Topics, Concepts,
Review Questions
Information, Vocabulary, Main Points: YOUR NOTES
GROUND • Water found beneath the
WATER
earth’s surface.
• Nearly all water is being
recycled; little is stored.
• Residence time refers to
the amount of time water
is stored.
• May be used right away or
stored for thousands of
years.
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Topic: Water Quality Notes
Topics, Concepts, Review
Questions
Zone of
Aeration
Information, Vocabulary, Main Points: YOUR NOTES
• Layer of groundwater
closest to the soil’s
surface; spaces in soil fill
with water and air.
• Under the zone of
Zone of
aeration, this layer has all
Saturation
open spaces filled with
water.
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Topic: Water Quality Notes
Topics, Concepts, Review
Questions
Water
Table
Information, Vocabulary, Main Points: YOUR NOTES
• Found at the upper edge
of the zone of saturation
and the bottom edge of
the zone of aeration.
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Topics, Concepts, Review Questions
Information, Vocabulary, Main Points: YOUR NOTES
a change in temperature will
affect the amount of
dissolved oxygen that the
water can hold.
How do
aquatic
organisms get
O2 for
respiration?
They do not break water
molecules apart!!!
They absorb dissolved O2
gas through their skin or
through special respiratory
structures. (DO)
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Topics, Concepts, Review
Questions
Information, Vocabulary, Main Points: YOUR NOTES
DO (dissolved Amount of oxygen gas
oxygen):
that is dissolved in water
Enters water by
diffusion from the
atmosphere.
Also can enter by
aquatic plant or algal
photosynthesis
Removed by respiration
and decomposition
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Topics, Concepts,
Review Questions
Information, Vocabulary, Main Points: YOUR NOTES
Water is mixed with air as it
falls over rocks and waterfalls.
Fast-moving bodies of water
and wave action—higher DO
levels.
Standing/slow-moving water
bodies—lower DO levels.
Determines types of
organisms in aquatic
ecosystems.
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Topics, Concepts, Review Questions
Information, Vocabulary, Main Points: YOUR NOTES
Photosynthesis
in algae &
Increases dissolved O2
aquatic plants: during daylight hours.
Why do DO
levels drop at
night & on
cloudy days?
Because photosynthesis
is not occurring & all
organisms, including
plants & algae, use O2
for respiration.
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Topics, Concepts, Review
Questions
Why does
DO
decrease
the
deeper
you go in
a lake
and
ocean?
Information, Vocabulary, Main Points: YOUR NOTES
Deep water can’t readily mix
with the air—no diffusion.
No sunlight penetration—no
photosynthesis.
Decomposers & scavengers
utilize any DO left in the
benthic environments.
Aquatic biodiversity indicates
water with a high level of DO,
from 5 ppm to 10 ppm.
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Topics, Concepts, Review Questions
Information, Vocabulary, Main Points: YOUR NOTES
Less DO than clean water.
Organic
Bacteria & other decomposers
matter
pollution: use oxygen for processes of
decay.
When DO is depleted, anaerobic
bacteria (decomposers) take over
the job of decomposition.
Waste products from anaerobic
respiration = stinky water!
Insufficient DO levels cause
more fish kills than any other
event, including oil spills. This 10
lowers the DO even further!
Topics, Concepts, Review Questions
•Fish such as
trout & salmon
require high
levels of DO &
are found in cold
water.
•Warm water
fish like carp
and catfish can
survive in water
with very low
levels of DO.
Information, Vocabulary, Main Points: YOUR NOTES
As the water
temperature increases
(gets warmer), the
water retains less DO
(oxygen escapes as a
gas into the air).
In contrast, cooler
water can hold more
DO.
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Topics, Concepts, Review Questions
Information, Vocabulary, Main Points: YOUR NOTES
Thermal pollution occurs
Most water
when hot water is dumped
used by
factories (esp. into aquatic ecosystems.
nuclear power
plants) is used
for cooling.
Warmer water cannot
hold as much DO.
Some companies build
cooling towers or holding
reservoirs (man-made
lakes) that permit the
water to cool before it
enters the natural aquatic
ecosystem.
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Topics, Concepts, Review
Questions
Information, Vocabulary, Main Points: YOUR NOTES
Biochemical  When bacteria break
down organic runoff, it is
oxygen
measure as BOD.
demand
 The amount of oxygen
(BOD):
consumed (demanded) by
microorganisms and
combined with chemicals
in the water.
 If BOD is 5 mg/L or
higher, the water quality
is poor.
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Topics, Concepts, Review
Questions
pH:
Information, Vocabulary, Main Points: YOUR NOTES
A measure of a solution’s acidity
or alkalinity.
The measurement of the number
of hydrogen ions in water, from a
scale of 0 to 14.
<7: acidic
=7: neutral
>7: basic
pH scale is logarithmic, so each
whole # is 10X the preceding one.
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The pH Scale:
The color distribution of the chart represents
the indicator colors of Hydrion paper that is
used to determine the pH of liquids.
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Topics, Concepts, Review
Questions
pH:
Information, Vocabulary, Main Points: YOUR NOTES
Few organisms live in water
with a pH lower than 4 or
higher than 9.
Natural waters are between 69.
Most species have a narrow
range of pH where they can
grow & reproduce.
Determines kinds of animals &
plants that can live there.
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Topics, Concepts, Review Questions
Water pH
between 6.5
& 8.2
supports
diversity.
Information, Vocabulary, Main Points: YOUR NOTES
At 6.5 snails & tadpoles
begin to die, salmon &
trout reproduction
declines, and mayfly &
caddisfly populations
decline.
At 5.5 decomposers
begin to die.
A pH above 9 harms
salmon, trout, & perch.
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Topics, Concepts, Review Questions
Water pH is
affected by
several
factors:
Information, Vocabulary, Main Points: YOUR NOTES
Lakes and ponds are basic
(alkaline) when first formed.
Organisms produce CO2
during respiration & when
they die, more CO2 is
produced during
decomposition.
Carbonic acid (H2CO3) is
formed when CO2 is combined
with water.
The more carbonic acid
dissolved in the water, the
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lower the pH (higher acidity).
Topics, Concepts, Review
Questions
Information, Vocabulary, Main Points: YOUR NOTES
Water from industries may contain
chemicals that alter pH levels.
Trains, trucks, & tanker accidents
sometimes result in chemical spills.
Strip mining of coal ore causes
acid mine drainage into waterways—
when sulfur in rock formations gets
exposed to air & water, sulfuric
acid (H2SO3) is formed.
To prevent the formation of acid,
the sulfur minerals left behind must
be covered with soil.
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Topics, Concepts, Review Questions
Information, Vocabulary, Main Points: YOUR NOTES
Hardness: Determined by rocks & soil in the
watershed.
Water that lacks minerals is soft
water.
Ex: granite rocks do not
dissolve easily so water will
contain few minerals.
Water with a hardness of less
than 10 ppm can support few
plant/animal life.
Minerals include calcium &
magnesium, necessary for life.
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Topics, Concepts, Review Questions
Information, Vocabulary, Main Points: YOUR NOTES
What is a
buffer?
A substance that, when
placed in water, prevents
large changes in the pH that
could harm aquatic
organisms.
Neutralizes acids that
enter the water.
Alkalinity is a measure of
the buffering capacity of
water.
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Topics, Concepts, Review Questions
Information, Vocabulary, Main Points: YOUR NOTES
Hard water contains
mineral compounds that act
like buffers.
Aquatic ecosystems with hard
water are less affected by acid
rain than those that contain soft
water.
Nitrates
(NO3-):
Found in fertilizers.
Soluble in water.
Carried to nearby streams
& lakes when it rains.
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Topics, Concepts, Review
Questions
Information, Vocabulary, Main Points: YOUR NOTES
In sewage waste produced by humans
& animals.
1 cow produces waste equal to the
sewage produced by 4.5 humans.
Also released by the decomposition
of organic matter.
Nutrients for algae & aquatic plants.
Causes amplified algal growth which
leads to build-up of dead plant
material = increase in BOD & decrease
in DO. (Eutrophication)
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Topics, Concepts, Review Questions
Information, Vocabulary, Main Points: YOUR NOTES
Upper
Prevents growth of floating
reaches of plants & plankton algae even
stream:
when nitrogen levels are high.
Lower
reaches:
Water is warmer & slower
moving.
High nitrates cause abundant
algal growth = algal bloom.
When algae die & settle to the
bottom, their decay cause DO
levels to fall.
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Topics, Concepts, Review Questions
Why
should
drinking
water be
tested for
nitrates?
Information, Vocabulary, Main Points: YOUR NOTES
National standard for nitratenitrogen is 10 ppm.
Wells can be contaminated from
fertilizers & sewage.
Can cause the death of infants.
Special bacteria in baby’s
digestive system change nitrate
(NO2-) to nitrite, which enter
bloodstream causing
methemoglobinemia.
Oxygen cannot combine with
hemoglobin when nitrites are
present = “blue baby” syndrome can
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be fatal.
Topics, Concepts, Review Questions
Information, Vocabulary, Main Points: YOUR NOTES
Phosphates Phosphorus in this form is a
plant nutrient & stimulates
(PO4-3):
algae & aquatic plant growth like
nitrogen does.
This is usually the limiting
factor in aquatic ecosystems
(have low levels of P).
Inorganic phosphates (found in
fertilizers, detergents) are
attracted to soil particles, &
when erosion occurs, they enter
the water causing increased
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algal & plant growth.
Topics, Concepts, Review Questions
Information, Vocabulary, Main Points: YOUR NOTES
Organic phosphates are
present in human/animal
wastes.
Present in some detergents &
wastewater from industrial
processes.
Many states have banned the
use of phosphates in
detergents.
Turbidity: Greatest water-quality
problem.
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Topics, Concepts,
Review Questions
Information, Vocabulary, Main Points: YOUR NOTES
Soil erosion increases the solid
particles suspended in the water.
Phosphates attached to soil particles
& nitrates dissolved in water increase
plankton algae growth which increases
turbidity = less light penetration =
decreased photosynthesis.
i biodiversity.
Clogs fish gills; smothers benthos;
fish eggs & larvae do not develop =
disrupts the food chain.
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Erosion makes water in these streams
turbid & smothers aquatic organisms.
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Topics, Concepts, Review Questions
Why do
people
choose to
live along
rivers?
Information, Vocabulary, Main Points: YOUR NOTES
Provides a cheap & easy means
of transportation.
Source of water & irrigation.
Rich floodplain is suitable
farming land.
Provides waterpower that
attracts industry.
Dams built for hydroelectric power
(water flows through turbines to
turn generators that make
electricity).
Coal-fired power plants use water
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as a coolant.
Topics, Concepts, Review Questions
Information, Vocabulary, Main Points: YOUR NOTES
What
Amount of water that can be
happens as absorbed by the earth is
more land decreased.
Buildings, streets, parking lots
is
cover the land and prevent water
developed?
infiltration.
Precipitation runoff now flows
through pipes beneath the ground
called storm drain tunnels (replace
natural streams) that carry the
runoff to the nearest river.
City streets are flooded when
storm systems can’t carry water
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away fast enough.
Topics, Concepts, Review Questions
Flash
floods:
Information, Vocabulary, Main Points: YOUR NOTES
Occur within a few minutes or
hours of excessive rainfall.
Replacing forests w/parking
lots will increase runoff &
flooding.
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Topics, Concepts, Review Questions
Information, Vocabulary, Main Points: YOUR NOTES
What is a
Openings you see along
storm
curbs and in streets &
drain?
parking lots.
Carry rainwater/snowmelt
(stormwater) & transport it
to nearby lakes & streams.
Water & other debris that
enter storm drains do not go
through a treatment
facility.
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Topics, Concepts, Review Questions
Information, Vocabulary, Main Points: YOUR NOTES
How does
stormwater As it flows over our lawns
& driveways, it picks up
get
fertilizers, oil, chemicals,
polluted?
grass clippings, litter, pet
waste, etc.
The storm drain system
transports these
pollutants, now in the
water, to local lakes &
streams.
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Topics, Concepts, Review
Questions
Information, Vocabulary, Main Points: YOUR NOTES
What’s a Takes household water &
sanitary waste from toilets, sinks, &
sewer? showers & transports it to a
wastewater treatment
facility.
Water is treated first & then
gets discharged back to a lake or
stream.
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36
Topics, Concepts, Review Questions
Information, Vocabulary, Main Points: YOUR NOTES
What is a The low flat land along a
floodplain? stream or river that is
periodically flooded.
Value of a Natural storage area for
floodplain: excess water that river can’t
carry & recharge area for
groundwater supply.
Many large Depend upon floodwalls or
cities are levees for protection. Ex:
built on
Boston, Kansas City, St. Louis,
floodplains: Pittsburgh, New Orleans.
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Topics, Concepts, Review Questions
For many
years rivers
used to carry
wastewater
away from
cities.
Information, Vocabulary, Main Points: YOUR NOTES
The industrial revolution
& the invention of the
water closet (1st indoor
toilet) increased the
river’s load of wastes.
Rivers smelled of
sewage, and water-borne
diseases were prevalent.
This is pollution from a
dye company in China
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Topics, Concepts, Review
Questions
Information, Vocabulary, Main Points: YOUR NOTES
 Pollutants released directly
Point
into urban water supplies,
source
from factories, refineries &
Pollution
water treatment facilities
Nonpoint  Contaminants entering the
source
water supply from soils and
groundwater runoff, such as
Pollution
industrial waste, pesticide
residue & the atmosphere
(from automobiles, restaurants
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& factories)
Topics, Concepts,
Review Questions
1972
Clean
Water
Act:
Information, Vocabulary, Main Points: YOUR NOTES
Congress believed that all rivers
should be “fishable and swimmable.”
Federal water quality standards
required cities to treat their
sewage before dumping it into
rivers, etc.
Industries were required to use
“best practicable” technology to
stop pollution.
Today wastewater from point sources
(industries and sewer pipes) is now
being treated to remove pollutants. 40
Topics, Concepts, Review Questions
Sewage
Treatment
Plant:
Information, Vocabulary, Main Points: YOUR NOTES
Incoming sewage 1st flows
through a bar screen that
removes trash—large solids
(rags, sticks, etc.).
Trash is scraped from the
bars & taken to a landfill.
Purpose of
primary & To remove organic matter &
secondary nutrients—food for algae &
treatment: bacteria—from the sewage.
Removes 85% of organic
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matter & nutrients.
Topics, Concepts, Review Questions
Information, Vocabulary, Main Points: YOUR NOTES
Primary
Involves physical separation of
treatment- liquids and solids.
1/3 of the suspended solids
(organic matter) settles out in
the primary settling tanks.
Solids that sink to the bottom =
sludge (biosolids)
Floating grease & oils are
skimmed off the surface.
Sludge and effluent (partially
treated wastewater) are piped
to separate tanks for secondary
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treatment.
Topics, Concepts, Review Questions
Information, Vocabulary, Main Points: YOUR NOTES
Secondary Biological process that
treatment- increases DO & allows time for
organisms to remove organic
matter.
Activated sludge process: (for
cities w/less space) wastewater
from primary treatment is
piped to large tanks where air
is pumped into them.
Air supplies bacteria w/O2 they
need to break down the organic
matter in the sewage.
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Topics, Concepts,
Review Questions
Information, Vocabulary, Main Points: YOUR NOTES
Sludge from the primary & secondary
settling tanks is piped to digesters—
large tanks that are heated to 95ºF
where it is held for 15-20 days.
Here anaerobic bacteria in the waste
digest more of the organic material that
is left.
Natural gas or methane is a waste
product of this anaerobic digestion
process.Some methane is burned to
provide heat to run the digesters.
Excess methane also supplies heat for
buildings nearby.
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Use ALUM to separate sludge
Sewage Treatment Plant
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Topics, Concepts, Review Questions
What
happens to
remaining
biosolids
(sludge)?
Information, Vocabulary, Main Points: YOUR NOTES
Used as fertilizers and soil
enhancers.
However, if too many biosolids are
applied to the land, excess nitrogen
can leach into nearby bodies of water.
A farmer must know current
nutrient level of his soil & the
biosolids in order to calculate the
amount that can be safely applied.
Helps in restoring the land
after mining operations.
Used with earthworms to
make compost (black gold)—
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humus for soil.
Topics, Concepts, Review Questions
Information, Vocabulary, Main Points: YOUR NOTES
Chlorination: After secondary treatment,
wastewater gets disinfected before
discharged through an outfall pipe
into a body of water nearby.
Sodium hypochlorite (same
chemical found in bleach) is added
to effluent to kill any diseasecausing bacteria that might remain.
The purpose of sewage treatment
plants is to reduce organic matter &
lower the biochemical oxygen
demand (BOD) of the effluent. 47
Topics, Concepts, Review
Questions
Information, Vocabulary, Main Points: YOUR NOTES
The bacteria in the sewage plant
break down organic matter, but they
do not have the enzymes that are
necessary to break down toxic
wastes.
Since heavy metals prevent normal
plant growth, sludge (biosolids) must
be tested to ensure safety for soil &
fertilizers.
Industries must pretreat
wastewater before dumping it in
sewers to prevent input of heavy
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metals.
Topics, Concepts, Review Questions
Where
land is
available,
wetlands
can
replace
trickling
filters or
activated
sludge
processes:
Information, Vocabulary, Main Points: YOUR NOTES
Lagoons (shallow ponds) are
less expensive to build &
maintain than sewage
treatment plants.
Sewage is held for 20-30
days; in warm climates, algae
& bacteria provide primary &
secondary treatments.
Fish and bats are added to
feed on mosquito larvae &
adults.
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Topics, Concepts, Review Questions
Information, Vocabulary, Main Points: YOUR NOTES
Water hyacinths (floating aquatic
plant) are added to control odors
and their roots also filter the
nitrates & phosphates out of the
water.
Duckweed, watercress, or
cattails can be used in areas
w/cooler climates.
Good spots for bird watchers.
Land around these lagoons can be
planted with crops & fertilized &
irrigated w/recycled wastewater.50
Topics, Concepts, Review Questions
Information, Vocabulary, Main Points: YOUR NOTES
Wastewater Septic tank-soil absorption
treatment in systems = a large tank buried in
rural areas: the ground to treat sewage from
an individual home or business.
Solids settle to the bottom,
bacteria break down organic
matter, & the effluent flows
through perforated pipes into
the soil absorption field (drain
field).
The size of the septic tank is
based on the number of
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bedrooms in the home.