Water Pollution & Cleanup
1
• Water pollution can be defined in many ways. Usually, it means one or
more substances have built up in water to such an extent that they cause
problems for animals or people. Oceans, lakes, rivers, and other inland
waters can naturally clean up a certain amount of pollution by dispersing it
harmlessly. If you poured a cup of black ink into a river, the ink would
quickly disappear into the river's much larger volume of clean water. The
ink would still be there in the river, but in such a low concentration that
you would not be able to see it. At such low levels, the chemicals in the ink
probably would not present any real problem. However, if you poured
gallons of ink into a river every few seconds through a pipe, the river
would quickly turn black. The chemicals in the ink could very quickly have
an effect on the quality of the water. This, in turn, could affect the health
of all the plants, animals, and humans whose lives depend on the river.
11 June 2010 Water-Pollution.ppt 2
Water pollution
• Classes of pollution, pollutants
– Pathogens, parasites
– Oxygen-demanding wastes
– Inorganic chemicals
– Inorganic plant nutrients
– Organic chemicals
– Sediments
– Radioactive material
– Heat (thermal pollution)
3
Water pollution
• Pathogens, parasites
– Usually from sewage, feedlots, slaughterhouses
– Viruses
– Bacteria (cholera, ...)
• Coliform bacteria usually not pathogenic,
• Used as indicators of pollution
– Protozoan parasites (Giardia, Cryptosporidium)
4
Water pollution
• Oxygen-demanding wastes
– Organic materials from sewage,
slaughterhouses, etc.
– Decomposed by bacteria
• Bacteria require, consume dissolved oxygen
– “Biological Oxygen Demand” (BOD)
• Measure of water quality
• Low in pristine water
5
Water pollution
• Inorganic chemicals
– Mostly from industry
– Heavy metals
• Lead, arsenic, mercury, copper ions, etc.
– Ammonia
– Acids
• Sulfuric acid, nitric acid from acid deposition
• Also from industry
– Bases (caustic alkalines)
6
Water pollution
• Inorganic plant nutrients (fertilizers)
– From agriculture, lawns & gardens
• Leaching into groundwater
• Run-off into surface waters
– Stimulate growth of algae (algal blooms),
eutrophication
• Algae die, sink, become oxygen-demanding
waste
7
Water pollution
• Inorganic plant nutrients
(fertilizers)
– From agriculture, lawns
& gardens
– Eutrophication
• Natural process
• Accelerated by excess
nutrient input
• Algae die, sink, become
oxygen-demanding waste
8
Water pollution
• Organic chemicals
– from industry, restaurants, cars, households,
farms
– Gasoline, oil
– Engine coolant (ethylene glycol)
– Solvents
– Detergents
– Pesticides
• insecticides, herbicides, fungicides
– Polychlorinated Biphenyls (PCBs)
9
Water pollution
• Sediments
– Erosion from construction sites, streets &
roads, farms, sewage
– Dense sediments sink, accumulate
• Sedimentation in reservoirs
– Less dense sediments may stay in water
• Reduce clarity (increase turbidity)
• Reduce light penetration & photosynthesis
10
Water pollution
• Radioactive material
– From spills, waste from atomic weapons production
• Hanford, Washington
• Savannah River Plant, South Carolina
– From nuclear power plants (minor)
• Closely regulated
• Heat (“thermal pollution”)
– Heated water from cooling of electrical generating
equipment
– Alters ecosystem of river, lake
11
Water pollution
• Non-point and Point sources
12
Ground water pollution
• Pollution of aquifers
• Non-point and Point sources
– Pollutants slow to break down in cold & dark
13
Water pollution
• In lakes, reservoirs
– Low flow rate, long
residence time
– Deep, stratification
– Pollutants can
accumulate, concentrate
14
Water pollution
• In streams, rivers
– Higher flow rate, dilution
effect
– Turbulent
• Well mixed
• Well oxygenated
– Long riverbanks, contact
with land
• Subject to non-point
source pollutants
– Often flow near cities
15
Water pollution
• Prevention
– Better to NOT pollute than to clean up later
• Clean up is expensive
• Clean up is never complete
16
Sewage Treatment
• Primary
– Screens and settling tanks remove grit &
suspended organic matter.
• Secondary
– Sewage aerated; aerobic bacteria consume organic
matter
– Leave dissolved inorganics, NO3, PO4, etc.
• Tertiary
– Filters most dissolved inorganics and remaining
dissolved organic compounds
17
Sewage Treatment
• Primary
– Screens and settling tanks remove grit &
suspended organic matter.
18
Sewage Treatment
• Secondary
– Sewage aerated; aerobic bacteria consume organic matter
– Leave dissolved inorganics, NO3, PO4, etc.
19
Sewage Treatment
• Tertiary
– Filters most dissolved
inorganics and
remaining dissolved
organic compounds
– Can be done
biologically in wetlands
• Natural
• Artificial
20
Water Quality
• Improvement since 1970
– Surface waters no longer regarded as open
sewers
• More and better sewage treatment systems
• Less dumping of industrial waste
– Clean Water Act of 1972, 1977
• Make all U.S. surface waters “fishable and
swimmable,”
– Goal not fully met
21
Table 22-2 Common Diseases Transmitted to Humans Through Contaminated Drinking Water
Type of Organism Disease Table 22-2Effects
Diarrhea, severe vomiting, enlarged
Bacteria Typhoid fever
Page 493 spleen, inflamed intestine; often fatal if
untreated
Cholera Diarrhea, severe vomiting, dehydration;
often fatal if untreated
Bacterial dysentery Diarrhea; rarely fatal except in infants
without proper treatment
Enteritis Severe stomach pain, nausea, vomiting;
rarely fatal
Viruses Infectious hepatitis Fever, severe headache, loss of appetite,
abdominal pain, jaundice, enlarged liver;
rarely fatal but may cause permanent liver
damage
Parasitic protozoa Amoebic dysentery Severe diarrhea, headache, abdominal
pain, chills, fever; if not treated can cause
liver abscess, bowel perforation, and death
Giardiasis Diarrhea, abdominal cramps, flatulence,
belching, fatigue
Parasitic worms Schistosomiasis
Abdominal pain, skin rash, anemia, chronic
fatigue, and chronic general ill health
Water DO (ppm) at 20˚C
Quality
Good 8-9
Slightly 6.7-8
polluted
Moderately
4.5-6.7
polluted
Heavily
Below 4.5
polluted
Gravely
Below 4
polluted
NONPOINT SOURCES
Rural homes
Urban streets Cropland
Animal feedlot
Suburban POINT
development SOURCES
Factory
Wastewater
treatment
plant
Normal clean water organisms
Trash fish (trout, perch, bass,
Fish absent,
Trash fish (carp, gar, mayfly, stonefly)
fungi,
Normal clean water organisms (carp, gar, sludge leeches) 8 ppm
Types of (trout, perch, bass, leeches) worms,
organisms mayfly, stonefly) bacteria
(anaerobic)
Dissolved 8 ppm
oxygen
(ppm)
Biological Clean Zone
oxygen
Recovery
demand
Septic Zone Zone
Decomposition
Clean Zone Zone
Animation
Stream pollution animation.
Click to view
animation.
Water
0.000002 ppm
Phytoplankton
0.0025 ppm Herring gull
124 ppm
Herring gull eggs
124 ppm
Zooplankton
0.123 ppm
Lake trout
4.83 ppm
Rainbow smelt
1.04 ppm
Nitrogen compounds
produced by cars
and factories
Discharge of untreated
municipal sewage
(nitrates and phosphates)
Discharge of Natural runoff
detergents (nitrates and
( phosphates) phosphates Inorganic fertilizer runoff
(nitrates and phosphates)
Manure runoff
from feedlots
Discharge of treated (nitrates, phosphates,
municipal sewage ammonia)
(primary and secondary
treatment: Runoff from streets,
nitrates and phosphates) Lake ecosystem lawns, and construction
nutrient overload lots (nitrates and
and breakdown of phosphates)
chemical cycling
Dissolving of Runoff and erosion
nitrogen oxides (from cultivation,
(from internal combustion mining, construction,
engines and furnaces) and poor land use)
Figure 22-7
Page 499
Polluted air
Hazardous waste
injection well
Pesticides
and
Coal strip De-icing fertilizers
mine runoff road salt Buried gasoline
and solvent tank
Pumping Cesspool
Gasoline station septic tank
well
Water
Waste lagoon pumping well
Sewer
Landfill
Leakage
Accidental from faulty
spills casing
Discharge
Confined
aquifer
Groundwater
flow
Solutions
Groundwater Pollution
Prevention Cleanup
Find substitutes for toxic Pump to surface, clean,
chemicals and return to aquifer
Keep toxic chemicals out of the (very expensive)
environment
Install monitoring wells near
landfills and underground tanks Inject microorganisms to clean
up contamination (less
Require leak detectors on expensive but still costly)
underground tanks
Ban hazardous waste disposal Pump nanoparticles of
in landfills and injection wells inorganic compounds to
remove pollutants (may be the
Store harmful liquids in cheapest, easiest, and most
aboveground tanks with leak effective method but is still
detection and collection systems being developed)
Industry Cities Urban sprawl Construction sites
Nitrogen oxides from autos Toxic metals and Bacteria and Sediments are washed into waterways,
and smokestacks; toxic oil from streets and viruses from sewers choking fish and plants, clouding
chemicals, and heavy parking lots pollute and septic tanks waters, and blocking sunlight.
metals in effluents flow waters; sewage contaminate shellfish
into bays and estuaries. adds nitrogen and beds and close Farms
phosphorus. beaches; runoff Run off of pesticides, manure, and
of fertilization from fertilizers adds toxins and excess
lawns adds nitrogen nitrogen and phosphorus.
and phosphorus.
Red tides
Excess nitrogen causes explosive
Closed
shellfish beds growth of toxic microscopic algae,
Closed poisoning fish and marine mammals.
beach Oxygen-depleted
zone
Toxic sediments
Chemicals and toxic metals
contaminate shellfish beds,
kill spawning fish, and
accumulate in the tissues
of bottom feeders.
Healthy zone
Clear, oxygen-rich waters
Oxygen-depleted zone promote growth of plankton
Sedimentation and algae and sea grasses, and support fish.
overgrowth reduce sunlight,
kill beneficial sea grasses,
use up oxygen, and degrade habitat.
Figure 22-12
Page 505
Mississippi
River Basin Ohio
River
Missouri
River
Mississippi
River
LOUISIANA
Mississippi
River
Depleted
Oxygen
Gulf of Mexico
NEW YORK
Figure 22-13
Cooperstown
PENNSYLVANIA
Page 506
ATLANTIC
Harrisburg OCEAN
NEW
JERSEY
MARYLAND
Baltimore
Washington
WEST DELAWARE
VIRGINIA
Richmond
VIRGINIA Norfolk Chesapeake Bay
Drainage No oxygen Low concentrations
basin of oxygen
Solutions
Coastal Water Pollution
Prevention Cleanup
Reduce input of toxic pollutants
Improve oil-spill cleanup
Separate sewage and capabilities
storm lines
Ban dumping of wastes and Sprinkle nanoparticles over an
sewage by maritime and cruise oil or sewage spill to dissolve
ships in coastal waters the oil or sewage without
Ban ocean dumping of sludge and creating harmful byproducts
hazardous dredged material (still under development)
Protect sensitive areas from
development, oil drilling, and oil Require at least secondary
shipping treatment of coastal sewage
Regulate coastal
development Use wetlands, solar-aquatic, or
Recycle used oil other methods to treat sewage
Require double hulls for oil tankers
Figure 22-14
Page 508
Septic tank with
manhole (for cleanout)
Household
wastewater Nonperforated pipe
Distribution box (optional)
Gravel or Drain
crushed field
stone Vent pipe
Figure 22-15
Perforated pipe
Page 510
Primary
Figure 22-16 Secondary
Grit
Page 511 Chlorine
Bar screen chamber Settling tank Aeration tank Settling tank disinfection tank
To river, lake,
or ocean
Raw sewage
from sewers Sludge (kills bacteria)
Activated sludge
Air pump
Sludge digester
Sludge drying bed
Disposed of in landfill or
ocean or applied to cropland,
pasture, or rangeland
Odors
Odors may cause illness or indicate
presence of harmful gases
Dust Particles
Particles of dried sludge carry
viruses and harmful bacteria that
can be inhaled, infect cuts or enter
homes.
Exposure
BUFFER ZONE
Children may walk or
play in fertilized fields.
Livestock Poisoning
Cows may die after grazing
Sludge on sludge-treated fields.
Groundwater
Contamination Surface Runoff
Harmful chemicals and Harmful chemicals and
pathogens may leach pathogens may pollute
into groundwater and nearby streams, lakes,
shallow wells. ponds, and wetlands.
Figure 22-17
Page 512
(1) Raw sewage drains by
gravity into the first pool
and flows through a long
Figure 22-18 (3) Wastewater flows through
another perforated pipe
into a second pool, where
perforated PVC pipe into the same process is repeated.
a bed of limestone gravel.
Page 513
Sewage
Treated
water
Wetland type Wetland type
plants plants
45 centimeter
layer of limestone
gravel coated with
First concrete pool decomposing bacteria Second concrete pool
(2) Microbes in the limestone gravel (4) Treated water flowing from the
break down the sewage into second pool is nearly free of
chemicals that can be absorbed bacteria and plant nutrients.
by the plant roots, and the gravel Treated water can be recycled
absorbs phosphorus. for irrigation and flushing toilets.
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 22-19
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 22-20
Page 516
