Transcript Water Pollution

Water Pollution
Chapter 22
John Todd’s Living Machine
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Sewage flows into passive solar
greenhouse or outdoor sites containing
rows of large open tanks
1st tanks- algae & microorganisms
decompose organic wastes
Water hyacinths, cattails, bulrushes,
other aquatic plants use remaining
nutrients
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Water runs through artificial marsh
(sand, gravel, bulrush plants) that
filters out algae & remaining organic
wastes
Aquarium tasks- snails & zooplankton
consume microorganisms & in turn
are consumed by crayfish, tilapia,
other fish & can be eaten or sold as
bait
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10 days later- 2nd artificial marsh
Purified for drinking by exposing to UV
light or passing through ozone
generator
Water Pollution

Any chemical, biological, or physical
change in water quality that has a
harmful effect on living organisms or
makes water unsuitable for desired
uses
Table 22-1 Major Categories of Water Pollutants
Table 22-1
Examples:
Bacteria, viruses,
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492protozoa, and parasitic worms
INFECTIOUS AGENTS
Major Human Sources: Human and animal wastes
Harmful Effects: Disease
Table 22-1 Major Categories of Water Pollutants
Table 22-1
Examples:
Organic waste
such as animal manure and plant debris that can be
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492
decomposed by aerobic (oxygen-requiring) bacteria
OXYGEN-DEMANDING WASTES
Major Human Sources: Sewage, animal feedlots, paper mills, and food processing
facilities
Harmful Effects: Large populations of bacteria decomposing these wastes can degrade
water quality by depleting water of dissolved oxygen. This causes fish and other forms of
oxygen-consuming aquatic life to die.
Table 22-1 Major Categories of Water Pollutants
Table 22-1
Examples:
Water-soluble
1) acids, (2) compounds of toxic metals such as lead (Pb),
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492
arsenic (As), and selenium Se), and (3) salts such as sodium chloride (NaCl) in ocean
INORGANIC CHEMICALS
water and fluorides (F–) found in some soils
Major Human Sources: Surface runoff, industrial effluents, and household cleansers
Harmful Effects: Can (1) make fresh water unusable for drinking or irrigation, (2) cause
skin cancers and crippling spinal and neck damage (F–), (3) damage the nervous
system, liver, and kidneys (Pb and As), (4) harm fish and other aquatic life, (5) lower
crop yields, and (6) accelerate corrosion of metals exposed to such water.
Table 22-1 Major Categories of Water Pollutants
Table 22-1
Examples:
Oil, gasoline,
plastics, pesticides, cleaning solvents, detergents
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492
ORGANIC CHEMICALS
Major Human Sources: Industrial effluents, household cleansers, surface runoff from
farms and yards
Harmful Effects: Can (1) threaten human health by causing nervous system damage
(some pesticides), reproductive disorders (some solvents), and some cancers
(gasoline, oil, and some solvents) and (2) harm fish and wildlife.
Table 22-1 Major Categories of Water Pollutants
Table 22-1
Examples:
Water-soluble
compounds containing nitrate (NO
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492
ammonium (NH ) ions
PLANT NUTRIENTS
4
3
–),
phosphate (PO43–), and
+
Major Human Sources: Sewage, manure, and runoff of agricultural and urban fertilizers
Harmful Effects: Can cause excessive growth of algae and other aquatic plants, which
die, decay, deplete water of dissolved oxygen, and kill fish. Drinking water with
excessive levels of nitrates lowers the oxygen-carrying capacity of the blood and can kill
unborn children and infants (“bluebaby syndrome”).
Table 22-1 Major Categories of Water Pollutants
Table 22-1
Examples:
Soil, silt 492
Page
SEDIMENT
Major Human Sources: Land erosion
Harmful Effects: Can (1) cloud water and reduce photosynthesis, (2) disrupt aquatic
food webs, (3) carry pesticides, bacteria, and other harmful substances, (4) settle out
and destroy feeding and spawning grounds of fish, and (5) clog and fill lakes, artificial
reservoirs, stream channels, and harbors.
Table 22-1 Major Categories of Water Pollutants
Table 22-1
Examples:
Radioactive
isotopes of iodine, radon, uranium, cesium, and thorium
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492
RADIOACTIVE MATERIALS
Major Human Sources: Nuclear and coal-burning power plants, mining and processing
of uranium and other ores, nuclear weapons production, natural sources
Harmful Effects: Genetic mutations, miscarriages, birth defects, and certain cancers
Table 22-1 Major Categories of Water Pollutants
Table 22-1
Examples:
Excessive 492
heat
Page
HEAT (THERMAL POLLUTION)
Major Human Sources: Water cooling of electric power plants and some types of
industrial plants. Almost half of all water withdrawn in the United States each year is
for cooling electric power plants.
Harmful Effects: Lowers dissolved oxygen levels and makes aquatic organisms more
vulnerable to disease, parasites, and toxic chemicals. When a power plant first opens or
shuts down for repair, fish and other organisms adapted to a particular temperature
range can be killed by the abrupt change in water temperature—known as thermal
shock.
Coliform Bacteria Count
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Presence indicates that water has
been exposed to human or animal
waste (contains disease causing
agents)
Dissolved Oxygen
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Related to the amount of oxygendemanding wastes (broken down by
oxygen-requiring bacteria & plant
nutrients)
Biological Indicators
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Analyze aquatic plants (cattails) or
bottom-dwellers (mussels) or filter
feeders
Point Source Pollution
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Discharge of pollutants at specific
locations through drain pipes, ditches,
or sewer lines into surface water
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Factories
Underground mines
Sewage treatment plants
Oil tankers
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Easy to identify, monitor, & regulate –
due to specific location
Nonpoint Source Pollution
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Large or dispersed land areas that
discharge pollutants into environment
over a large area
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Acid deposition
Runoff from croplands, feedlots for
livestock, logged forests, urban streets,
lawns, golf courses, parking lots
Safe Drinking Water
+ 74-95% of people have access to clean
drinking water
- 1.4 billion people do NOT
- 9,300 die daily due to infectious
diseases spread by contaminated
water or lack of water for adequate
hygiene
Developing Countries
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26% of people do not have access to
clean drinking water
Decreased Quality of Surface
Water
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Intense downpours = more chemicals,
plant nutrients, & microorganisms
Massive flooding = spread of disease
carrying pathogens into water
treatment facilities & wells
Overflow of lagoons & sewer lines =
raw sewage into rivers & streams
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Drought = reduced river water to dilute
waste
Spread of disease due to lack of water
to keep clean
Warm temperatures = lower dissolved
oxygen levels = higher growth rates of
bateria
Pollution of Streams
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Overloaded with pollutants
Drought
Damming or water diversion
Oxygen sag curve – depletion of DO
by bacteria = reduced populations of
organisms with high oxygen
requirements
Types of
organisms
Normal clean water organisms
(trout, perch, bass,
mayfly, stonefly)
Trash fish
(carp, gar,
leeches)
Fish absent,
fungi,
sludge
worms,
bacteria
(anaerobic)
Trash fish
(carp, gar,
leeches)
Normal clean water organisms
(trout, perch, bass,
mayfly, stonefly)
8 ppm
Dissolved 8 ppm
oxygen
(ppm)
Biological
oxygen
demand
Clean Zone
Septic Zone
Clean Zone
Recovery
Zone
Decomposition
Zone
Figure 22-5
Page 496
Limiting Factors
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Volume of degradable waste
Stream volume
Flow rate
Temperature
pH level
Controlling Stream Pollution in
Developed Countries
+ Increased number & quality of waterwater treatment plants
+ Industries are required to reduce or
eliminate point-source pollution
- Accidental or deliberate release of toxic,
inorganic, & organic chemicals causes
fish kills & contaminates drinking water
- Sewage treatment plants malfunction
- Nonpoint runoff of pesticides & excess
plant nutrients from cropland & animal
feedlots
Controlling Stream Pollution in
Developing Countries
- Discharge of untreated sewage &
industrial waste
- Only 10% of Chinese city sewage is
treated
Ganges River
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Cremated bodies are returned to river
(to increase chances for heaven)
Bodies are burned in open air wood
fires
Some bodies are dumped into river
only partially burned (decreases DO &
adds bacteria & viruses)
Government adding sewage treatment
plants & electric crematoriums
Diluting Lake Pollution
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Less effective
Stratified layers with little vertical
mixing
Little flow – water is replaced every 1100 years (unlike days to weeks for
streams)
Eutrophication
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Physical, chemical, & biological
changes that take place after receiving
inputs of plant nutrients (nitrates &
phosphates) from natural erosion &
runoff
Cultural Eutrophication
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Over nourishment of aquatic
ecosystems with plant nutrients due to
human activities (agriculture,
urbanization, & discharge from
industrial plants & sewage treatment
plants
Eutrophication Prevention
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Use advances (& expensive) waste
treatment systems to remove nitrates
& phosphates from waste water
Ban (or limit) use of phosphate in
household detergents & other cleaning
agents
Soil conservation & land-use control to
reduce nutrient runoff
Eutrophication Cleanup
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Mechanically remove excess weeds
Control plant growth with herbicides &
algaecides
Pump air through lakes & reservoirs to
avoid oxygen depletion
Lake Washington
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Water was diverted into Puget Sound
Puget sound has rapid exchange rate
with Pacific Ocean
Lake was NOT filled with weeds &
sediment
Preventative action
The Great Lakes
+ Decreased algal blooms
+ Increased DO levels
+ Increased commercial fishing catches
+ New or upgraded sewage treatment
plants
+ Better treatment of industrial wastes
+ Ban of phosphate containing cleansers
- August- low DO levels – kills fish &
microorganisms
- ¾ of shoreline is NOT clean enough for
swimming
- Nonpoint pollution is still high
- Highly polluted sediments in hot spots
- 80% drop in EPA funded cleanup
Groundwater Contamination
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Leaking from industrial waste ponds
(no liners)
Leaking of underground tanks
(gasoline, diesel fuel, home heating oil,
& toxic solvents)
Leaching of nitrate fertilizers
Soils & rock may contain arsenic
High levels of naturally occurring
fluoride
Serious Problems because
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Removal can be difficult & costly
Slow water movement
Pollutants can get easily into drinking
water & irrigation water
As a Result
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High fluoride levels= crippling spine &
neck damage & variety of dental
problems
High nitrate levels= cancers & “blue
baby syndrome” (blood lacks the ability
to carry sufficient oxygen)
High arsenic level= cancer (skin,
bladder, lung)
Solutions
Figure 22-10
Page 503
Groundwater Pollution
Prevention
Find substitutes for toxic
chemicals
Keep toxic chemicals out of the
environment
Install monitoring wells near
landfills and underground tanks
Require leak detectors on
underground tanks
Ban hazardous waste disposal
in landfills and injection wells
Store harmful liquids in
aboveground tanks with leak
detection and collection systems
Cleanup
Pump to surface, clean,
and return to aquifer
(very expensive)
Inject microorganisms to clean
up contamination (less
expensive but still costly)
Pump nanoparticles of
inorganic compounds to
remove pollutants (may be the
cheapest, easiest, and most
effective method but is still
being developed)
Ocean Pollution
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Coastal areas- dumping of sewage &
industrial waste, agricultural waste,
algal blooms, oxygen-depleted zones
(excessive fertilizers & animal wastes)
40% of world population lives with
100km (62mi) of coast
Ocean Pollution from Rivers
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Plant nutrients from river systems –
causes algal blooms (red, brown,
green) – releases waterborne &
airborne toxins that damage fisheries,
kills fish-eating birds, reduces tourism,
& poisons seafood
Chesapeake Bay
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Waste from point & nonpoint sources
Shallow bay
Sewage treatment & industrial plants
Runoff from urban, suburban, &
agricultural land
Deposition from atmosphere
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Integrated Coastal Management
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Land-using regulations for agricultural &
urban runoff
Ban phosphate detergents
Upgrade sewage treatment plants
Better monitoring of industrial discharge
Types of Ocean Pollution
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Dredge spoils- materials (toxic metals)
scraped from bottoms of harbors &
rivers to clear shipping channels
Sewage sludge- gooey mixture of toxic
chemicals, infectious agents, & settled
solids removed from wastewater at
sewage treatment plant
Ocean Oil Pollution
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Waste oil dumped on ground, poured
down drain, spilled, or leaked onto
land or into sewers by cities,
industries, & people changing motor oil
Oil & Ocean Ecosystem
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Kills aquatic organisms (especially
larval forms)
Coats bird feather & marine mammal
fur (destroys natural insulation &
buoyancy)
Smothers bottom-dwellers
Kills coral reef
Economic impact on coastal residents
Mechanical Cleanup
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Floating booms = contain oil spills from
reaching sensitive areas
Skimmer boats = vacuum up oil into
collections barges
Absorbent devices = large mesh pillow
filled with feathers or hair to soak up oil
on beaches
Chemical Methods
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Coagulating agents = cause floating oil
to clump together
Dispersing agents = break up oil slicks
Fire = can burn off floating oil, but
crude oil is hard to ignite & produces
air pollution
Cleanup Limitations
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Can only recover 15% of oil
Reduced Tanker Oil Spills
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Double hulls (by 2015)
Trust fund for cleanups
Banning of single hull tankersh
Figure 22-14
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Solutions
Coastal Water Pollution
Prevention
Reduce input of toxic pollutants
Separate sewage and
storm lines
Ban dumping of wastes and
sewage by maritime and cruise
ships in coastal waters
Cleanup
Improve oil-spill cleanup
capabilities
Ban ocean dumping of sludge and
hazardous dredged material
Sprinkle nanoparticles over an
oil or sewage spill to dissolve
the oil or sewage without
creating harmful byproducts
(still under development)
Protect sensitive areas from
development, oil drilling, and oil
shipping
Require at least secondary
treatment of coastal sewage
Regulate coastal
development
Recycle used oil
Require double hulls for oil tankers
Use wetlands, solar-aquatic, or
other methods to treat sewage
Reducing Nonpoint Source
Pollution
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Prevent soil erosion by keeping
cropland covered with vegetation
Use slow-release fertilizer
Apply pesticides only when needed
Use buffer zone around animal
feedlots, animal waste sites, &
cultivated fields
Use biological controls
Clean Water Act
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Standards for allowed levels of key
water pollutants & required polluters to
get permits for discharge
Water Quality Act
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Control pollution of surface water
EPA Discharge Trading Policy
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Uses market forces to reduce water
pollution
Septic Tanks
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Underground tank for treating
wastewater from a home in rural &
suburban areas
Bacteria decomposes organic waste
Sludge settles to bottom
Effluent flows out of tank into ground
Primary Sewage Treatment
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Mechanical sewage treatment where
large solids are filtered out by screens
& suspended solids settle out as
sludge in sedimentation tank
Secondary Sewage Treatment
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2nd step- aerobic bacteria decomposes
90% of degradable, oxygendemanding organic wastes
Sewage & bacteria is brought together
in trickling filters or in activated sludge
process
Household
wastewater
Gravel or
crushed
stone
Septic tank with
manhole (for
cleanout)
Nonperforated
pipe
Distribution box
(optional)
Drain
field
Vent pipe
Perforated
pipe
Figure 2215
Page 510
Figure 22-16 Page 511
Secondary
Primary
Bar screen
Grit
chamber
Settling tank
Aeration tank
Settling tank
Chlorine
disinfection tank
To river, lake,
or ocean
Raw sewage
from sewers
(kills bacteria)
Sludge
Activated sludge
Air pump
Sludge digester
Sludge drying bed
Disposed of in landfill or
ocean or applied to cropland,
pasture, or rangeland
Sludge
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Slimy mixture of bacteria-laden solids
& toxic chemicals & metals from
industrial & household waste
Used to make compost for soil
conditioning
Biosolids- used to fertilize farmlands,
forests, golf courses, cemeteries,
parkland, highway medians, &
degraded land
Sludge as Fertilizer
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Must remove harmful bacteria, other
pathogens, & toxic chemicals
Removal is expensive & rarely done
Toxic / Hazardous Waste
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Preventing it from reaching sewage
treatment plant:
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Require industries & businesses to
remove toxic & hazardous wastes from
waste water
Switch to waterless composting toilet
systems
Wetlands
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Sewage goes into sedimentation tanks
(solids settle out as sludge)
Liquid is pumped into oxidation ponds
where bacteria breaks down remaining
wastes
Water released 1 month later into
artificial marsh (plants & bacteria carry
out further filtration & cleansing)
Wastewater Garden
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Small, low-tech inexpensive artificial
wetland
Removes 99.9% of fecal coliform
bacteria
Removes 80% of nitrates &
phosphates from incoming sewage
(1) Raw sewage drains by
gravity into the first pool
and flows through a long
perforated PVC pipe into
a bed of limestone gravel.
(3) Wastewater flows through
another perforated pipe
into a second pool, where
the same process is repeated.
Sewage
Treated
water
Wetland type
plants
First concrete pool
Wetland type
plants
45 centimeter
layer of limestone
gravel coated with
decomposing bacteria
(2) Microbes in the limestone gravel
break down the sewage into
chemicals that can be absorbed
by the plant roots, and the gravel
absorbs phosphorus.
Figure 22-18 Page 513
Second concrete pool
(4) Treated water flowing from the
second pool is nearly free of
bacteria and plant nutrients.
Treated water can be recycled
for irrigation and flushing toilets.
U.S. Reduction of Water
Pollution
+ Increased to 94% of community water
systems met federal health standards
+ Fishable/swimmable areas increased to
60%
+ Topsoil loss cut by 1 billion tons
+ Sewage treatment plants increased
service to 74%
+ Annual wetland loss decreased to 80%
- 45% of lakes & 40% of streams were
too polluted for fishing or swimming
- Only 19% of streams, 43% of lakes, &
36% of estuaries have been tested for
water quality
- 70% of rivers are polluted by animal
waste from hog, poultry, & cattle
feedlots & meat processing facilities
- Fish caught in 25% of lakes are unsafe
to eat due to pesticides, mercury, or
other toxic substances
Strengthening CWA
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Increased funding & authority to
control nonpoint sources of pollution
Upgrade computer system for
monitoring compliance with the law
Strengthening programs to prevent &
control toxic water pollution
More integrated watershed & air shed
planning to protect groundwater &
surface water from contamination
Opposition
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CWA is too restrictive & costly
Curb on right of landowner to fill in
wetlands
Landowners want compensation for
property value losses
Water Purification
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Stored in reservoir for several days
(increases DO level & suspended
matter settles)
Water is pumped to purification plant
for filtration & chlorination
Vulnerability to Terrorist
Attacks
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Fear of added chemicals or biological
agents
Hard to protect due to large numbers
of reservoirs, vast network of
purification plants & distribution
systems, & accessibility of water
systems through fire hydrants &
service connections
Purification in Developing
Countries
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Exposing water in clear plastic bottle to
intense sunlight (heat & UV will kill
infectious microbes in 3 hrs)
Strips of cloth for filtering choleraproducing bacteria
Add small amount of chlorinedisinfectant solution to plastic or clay
storage containers with narrow mouth,
cap, & spigot
Protecting Drinking Water
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54 countries have standards for safe
drinking water
Safe Water Drinking Act- requires EPA
to establish national drinking water
standards (maximum contaminant
levels) for pollutants with adverse
effects on human health
Private wells are exempt
Success of Efforts
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Most of the 54 countries are in North
America & Europe
CWA laws do not exist or are not
enforces in developing countries
Strengthening U.S. SDWA
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Combine water treatment systems that
serve fewer than 3,300 people
Strengthen & enforce public
notification requirements about
violations of standards
Banning all toxic lead in pipes, faucets,
& fixtures
Weakening SWDA
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Eliminate national tests of drinking
water & public notification
requirements about violations of
standards
Give water systems permanent right to
violate standards if it cannot afford to
comply
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Eliminate requirement that water
systems remove cancer-causing
contaminants
Reduce EPA budget for enforcing
CWA
Bottled Water
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240-10,000X more expensive than tap
water
¼ of bottled water is tap water
Bacteria contaminates 1/3
Various potentially harmful organic
chemicals contaminate 1/5
1.5 million tons (bottles) trashed
globally
Manufacturing plastic water bottles
releases toxic gases & liquids
(greenhouse gases)
+++ Some tap water is too polluted to
drink
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Solutions
Water Pollution
• Prevent groundwater contamination
• Greatly reduce nonpoint runoff
•Reuse treated wastewater for irrigation
• Find substitutes for toxic pollutants
• Work with nature to treat sewage
• Practice four R's of resource use (refuse,
reduce, recycle, reuse)
• Reduce resource waste
• Reduce air pollution
• Reduce poverty
•Reduce birth rates
Figure 2219
Page 516
What Can You Do?
Water Pollution
•Fertilize your garden and yard plants with
manure or compost instead of commercial
inorganic fertilizer.
•Minimize your use of pesticides.
•Never apply fertilizer or pesticides near a
body of water.
•Grow or buy organic foods.
•Compost your food wastes.
•Do not use water fresheners in toilets.
•Do not flush unwanted medicines down the
toilet.
•Do not pour pesticides, paints, solvents, oil,
antifreeze, or other products containing
harmful chemicals down the drain or onto
the ground.
Figure 2220
Page 516