Water Pollution 2008

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					                                          Core Case Study: Using
                                          Nature to Purify Sewage

    Chapter 21                                                              Ecological wastewater
                                                                            purification by a living
                                                                              Uses the sun and a
    Water Pollution                                                           series of tanks
                                                                              containing plants,
                                                                              snails, zooplankton,
                                                                              crayfish, and fish (that
                                                                              can be eaten or sold
                                                                              for bait).        Figure 21-1

SOURCES, TYPES, AND                       Non-
                                          Non-Point Pollution
EFFECTS                                   Cultural eutrophication:
Water pollution is any chemical,             human activities accelerate
biological, or physical change in            the input of plant nutrients
water quality that has a harmful                      nitrate-
                                             (mostly nitrate- and
effect on living organisms or                effluents) to a lake.
makes water unsuitable for                   85% of large lakes near
desired uses.                                major population centers in
                                             the U.S. have some degree
                                             of cultural eutrophication.
  Point source: specific location
  (drain pipes, ditches, sewer lines).    Polluted Agriculture runoff
                                              #1 polluter of surface
  Nonpoint source: cannot be traced          waters in the U.S.
  to a single site of discharge              Chemical Pesticides
  (atmospheric deposition, agricultural      Animal wastes
  / industrial / residential runoff)

Municipal Waste Pollution                 Municipal Waste Pollution
                                              Rains washes pollutants
                                              off concrete and into
 Nonpoint pollution                           storm drains
 caused by cities waste
 Municipal waste is                           Flow untreated into the
 basically anything                           rivers and oceans
                                                  LB =“The Sewer by the
 that ends up on the                              Sea”

                                          Sediment Pollution
Types Of Water Pollution
• Catagories:                                Largest pollutant
 1. Sediment Pollution                       by volume in
 2. Sewage (Oxygen-depleting) &              most parts of
    Disease Causing Agents                   world
 3. Inorganic Plant & Algal Nutrients &
    Inorganic Chemicals (toxic)
 4. Organic Compounds
 5. Radioactive Substances
 6. Thermal Pollution

Effects of Sedimentation                   Sediment Pollution

                                             Reduces light penetration
                                                Turbidity (cloudiness)
                                             Covering aquatic organism
                                                Clog gills/feeding structures
                                                Kill corals
                                             Brings insoluble toxic pollutants into
                                             Fills in waterways

Disease-Causing Agents                     Water Born Diseases
                                             E.Coli, Amebic Dysentery, Cholera, Typhoid
                                                2/3 of child deaths
                                                80% of sickness in developing countries)
                                             Comes from untreated human wastes and
                                             animal wastes
                                             2.5 billion people lack sanitation
                                             1993 Milwaukee, Wisconsin
                                               Cryptosporidium ~ 370,000 sickened and some

                                               Detecting Sewage in
Sewage                                         Drinking Water

 •Sewer lines can break                         •E. coli is used as an
 or leak releasing
                                                indicator species to
 pathogens into
 groundwater or oceans:                         detect contaminated
 Orange County Beaches,                         water supplies
 E.Coli                                         because
                                                it grows only in
                                                human and
                                                animal feces

Major Water Pollutants
and Their Effects                               Testing for Unsafe Water
  Instead of testing for
  all types of bacteria,                            One colony of bacteria per 100ml is
  levels of coliform is                             considered unsafe to drink

    A fecal coliform
    bacteria test is used to
    indicate the likely
    presence of disease-
    causing bacteria in
    water.                              21-
                                 Figure 21-2

    Swimming 200/100mL
    Boating 2,000/100mL
    Raw sewage several million

                                                                                    Table 21-2, p. 495

FRESHWATER STREAMS                                                   Sag”
                                                             “Oxygen Sag”

  Flowing streams can recover from a                       •Pattern of DO2 in a
  moderate level of degradable water                       stream with pollutants
  pollutants if they are not overloaded and
  their flows are not reduced.
    In a flowing stream, the breakdown of                  •Pattern of organisms
    degradable wastes by bacteria depletes DO              is determined by DO2
    and creates and oxygen sag curve.
                                  curve.                   content
       This reduces or eliminates populations of
       organisms with high oxygen requirements.

Major Water Pollutants                                          Dissolved Oxygen is an indicator of water quality

and Their Effects                                             Water
                                                                                  DO (ppm) at 20    C

                                                               Good                                                                8–9


                                                            polluted                                           4.5–6.7

                                                            polluted                               Below 4.5
   Water quality and dissolved oxygen (DO)
   content in parts per million (ppm) at                    Gravely
                                                                                             Below 4
     Only a few fish species can survive in water
     less than 4ppm at 20°C.                       21-
                                            Figure 21-3                                                                  Fig. 21-3, p. 496

                                                            Measuring Oxygen
Oxygen-demanding Wastes                                     Content
  Healthy water = DO2> 8ppm                                BOD:
                                                           BOD: Biological Oxygen
  Oxygen-poor water (<2ppm) only
                                                              this measures the demand for
  supports detritivores                                       oxygen that the detritivores place
  O2 added diffusion at surface and                           on the system
  photosynthesis                                              how much O2 is used by
                                                              organisms over a 5 day period
  Oxygen is removed by respiration

 Oxygen-demanding Wastes
 Oxygen-                                                  Sag”
                                                  “Oxygen Sag”
   Addition of                                    •Length of oxygen
   sewage and
   wastes stimulates                              sag depend on:
   O2 consumption
   by detritivores                                   –How fast the
   Algal Blooms =                                    stream is
   eutrophication,                                   flowing
   fish kills
                                                     –How turbid
                                                      it is

 Water Pollution Problems
 in Streams
                                                                                                                       Normal clean s
                                                                                                           Trash fish      organism
                                                                                    Trash fish absent,     (carp, gar, (Trout, perch, bass,
                                                                          l clean                           leeches)     mayfly, stonef
                                                             Clean Norma       s    (carp, gar, fungi,
                                                  Types of s water organism s,       leeches) sludge
                                                  organism (Trout, perch, bas                                                         8 ppm
                                                               mayfly, stonef
                                                                              ly)                worms,
                                                  Dissolved                                      bacteria
                                                  oxygen                                       (anaerobic)
                                                  (ppm)     8 ppm
                                                  Biological                                                              Clean Zo
                                                  oxygen                                                   Recover
                                                  demand                              sition     Septic    Zone
                                                                              Decompo            Zone
    Dilution and decay of degradable,                          Clean Zo       Zone

    oxygen-demanding wastes and heat in a
                                    Figure 21-4                                                                                 Fig. 21-4, p. 497

Inorganic Plant And Algal
Nutrients                                         Red Tides
                                                  Storms bring nutrient-rich
                                                  runoff to the oceans
•Excess nitrates, phosphates cause                (Fertilizers, sewage, etc.)
                                                  Cause a phytoplankton bloom

                                Inorganic/algal Nutrients
Paralytic Shellfish Poisoning   Steps of Eutrophication
Dinoflagellate toxin,
concentrated by algal
                                   Nutrients are added to
Shellfish can wall the toxin
away - not affected                Increase in nutrients
                                   cause an algae bloom
60% fatality rate for top
carnivores (fish)                  As bloom progresses,
                                   algae begins to die
                                   Organic material
                                   accumulates on
                                   bottom of lake

Steps of Eutrophication

This material supports a
boom in the decomposer
The decomposers rapidly
rob the lake of its oxygen,
suffocating most other
organisms in the

                                        Controlling Eutrophication

                                        Nitrates and Phosphates
                                        can be removed before
                                        sewage is dumped into
                                        rivers or lakes by
                                        constructing wetlands:

Acids and Bases                         Inorganic Chemicals

                                        Heavy metals:
   Coal mining produces sulfuric acid
                                         Mercury, Coal fired
                                         Power Plants
   Acid rain (HNO3 and H2SO4)
                                         Lead pipes
                                         Gold mining
                                         Mining wastes
                                         Tin, Copper on boat

Groundwater Pollution                   Minimata, Japan
 MTBE, a gasoline
 MTBE,                                   Poor fishing and
 additive & suspected                    farming village
 carcinogen                                 Relatively closed
 250,000 leaking                            ecosystem
 tanks in country                                      Corp.
                                         1932 Chisso Corp.
 Contaminated ground                     began manufacturing
 water supplies of                       acetaldehyde
 Santa Monica.
 Closed 7 of 11 wells.                   Mercury byproduct
                                         was discharged
                                         into the bay.

After World War II, production boomed. Fish,
then cats showed
                           weird               1956: in humans as
                           behaviors.          successive loss of motor
                                               control resulted in partly
                                               paralyzed and
                                               contorted bodies.

Minimata Disaster                               1963: disease”
                                                1963: “disease” traced
                                                to mercury from
 Signatures,                                    Chisso
 before & after
                                                Forced to pay
                                                victims $3.2 million;
                                                had to dredge bay
                                                Main dumping area
                                                reclaimed as a
                                                1997: bay declared
                                                safe for fishing

 Organic Compounds                                       Clean-
                                               Oil Spill Clean-up
 Pesticides, oils,
 pigments, detergents,
 cleaning solutions, and

Ecological Problems                        Organic Chemicals

   Fills waterways,

Oil                                         •Most synthetic
•Oil spills have occurred in                organic
most of the shipping lanes in               compounds have
the world (as of 1985)                      chemical
•Large effects on sea surface               structures that
critters                                    microrganisms
•Ex. Exxon Mobile, Prince                   cannot decompose
William Sound                               •Persist in water

Nonmetallic Salts                            Plants cannot absorb water if soil is high in salts.
                                             Ex. Owens Valley
Occurs in desert soils
Evaporation leaves high levels of toxins
Road runoff: Selenium & Arsenic

Acids and Bases                     Radioactive Substances
Produced during                        Naturally occurring
leather tanning, metal                 radioactive gas that can
smelting, plating,                     enter homes through
petroleum distillation                 earth’
                                       earth’s crust or enter the
and organic chemical                   groundwater
                                    Radioactive materials
                                    can and have entered
                                    the groundwater

Thermal Pollution                   Thermal Pollution
  From industrial coolant
  outflows & Power Plants          Can be used for
  Water temps are usually          mariculture??
  stable:                          Can be harmful to
    Organisms poorly adapted       manatees
    to rapid change
                                    More chance of
  O2 solubility increases as
  temperature decreases

Eutrophication                     Eutrophication
 Water ecosystems (lakes) are
 usually limited by the amount     Humans artificially
                                   increase the amount
 of nutrients in them.
                                   of nutrients in lakes
 Through succession, lakes         through fertilizers,
 gradually increase in nutrients   run-
 and productivity                  The increase in
 Natural eutrophication leads      nutrients leads to a
 to marshes and wetlands over      series of steps
 long periods of time              culminating in

Controlling Eutrophication                           Controlling Eutrophication
                                                       Nitrates and
                                                       Phosphates can be
                                                       removed before
                                                       sewage is dumped into
                                                       rivers or lakes by
                                                       for that

                                                     POLLUTION OF
Controlling Eutrophication
                                                     FRESHWATER STREAMS
  Urban detergents and
  fertilizers should be
  used sparingly and be                                 Most developed countries have sharply
  phosphate-free when                                            point-
                                                        reduced point-source pollution but toxic
  possible                                              chemicals and pollution from nonpoint
  Eutrophic waters will                                 sources are still a problem.
  return to normal
  (ogligotrophic)                                       Stream pollution from discharges of
  if input of excess                                    untreated sewage and industrial wastes
  nutrients is stopped                                  is a major problem in developing

                                                     Case Study: India’s Ganges
Global Outlook: Stream
                                                     River: Religion, Poverty, and
Pollution in Developing                              Health
                          Water in many of              Religious beliefs, cultural traditions, poverty,
                                                        and a large population interact to cause severe
                          central China's               pollution of the Ganges River in India.
                          rivers are greenish              Very little of the sewage is treated.
                          black from                       Hindu believe in cremating the dead to free the soul
                          uncontrolled                     and throwing the ashes in the holy Ganges.
                          pollution by                       Some are too poor to afford the wood to fully cremate.
                                                             Decomposing bodies promote disease and depletes DO.
                          thousands of
                                       Figure 21-5

  Case Study: India’s Ganges                                                                            POLLUTION OF
  River: Religion, Poverty, and                                                                         FRESHWATER LAKES
                                                                                                          Dilution of pollutants in lakes is less effective
                                                      Daily, more than 1                                  than in most streams because most lake water
                                                      million Hindus in                                   is not mixed well and has little flow.
                                                      India bathe, drink                                    Lakes and reservoirs are often stratified and
                                                      from, or carry out                                    undergo little mixing.
                                                      religious                                             Low flow makes them susceptible to runoff.
                                                      ceremonies in the                                   Various human activities can overload lakes
                                                      highly polluted                                     with plant nutrients, which decrease DO and
                                                                                                          kill some aquatic species.
                                                      Ganges River.
                                                                                    Figure 21-6

                                                                                                        POLLUTION OF
    Cultural Eutrophication
              Eutrophication: the natural nutrient                                                        Groundwater can become contaminated
              enrichment of a shallow lake, estuary or slow
              moving stream, mostly from runoff of plant
                                                                                                          with a variety of chemicals because it
              nutrients from the surrounding land.                                                        cannot effectively cleanse itself and dilute
              Cultural eutrophication: human activities
                        eutrophication:                                                                   and disperse pollutants.
              accelerate the input of plant nutrients (mostly                                               The drinking water for about half of the U.S.
              nitrate-     phosphate-
              nitrate- and phosphate-containing effluents) to                                               population and 95% of those in rural areas
              a lake.                                                                                       comes from groundwater.
                85% of large lakes near major population centers in
                the U.S. have some degree of cultural

                                                                                                        POLLUTION OF
                                         Polluted air


                            and fertilizers
Coal strip
mine runoff
                    road salt                                  Buried gasoline
                                                               and solvent tanks
                                                                                                          It can take hundreds to thousand of years
                                                Gasoline station              Cesspool,
                                                                              septic tank
                                                                                                          for contaminated groundwater to cleanse
                                               pumping well
                                                                                                          itself of degradable wastes.
                  Waste lagoon                                    Sewer
                                              Landfill                                   Leakage
                                                                                                            Nondegradable wastes (toxic lead, arsenic,
                            spills                                                       casing             flouride)
                                                                                                            flouride) are there permanently.
                                                             r aq
                                                                                     Discharge              Slowly degradable wastes (such as DDT)
                                                     shw        ifer             Confined                   are there for decades.
                                              ed          r aqu                  aquifer
                                    con               ate
                                 Un               shw                    Groundwater
                                              fre                        flow
                                    n fi

                                                                                    Fig. 21-7, p. 501

                                                                                    POLLUTION OF
                                                                                            Leaks from a number of sources have
                                                                                            contaminated groundwater in parts of the
                                                                                                   According the the EPA, one or more organic
Water     rock                                                                                     chemicals contaminate about 45% of
                                                                                                   municipal groundwater supplies.
      flow    Free gasoline                                                                        By 2003, the EPA had completed the
Gasoline      dissolves in
leakage plume groundwater                                                                          cleanup of 297,000 of 436,000 underground
(liquid phase)(dissolved        Migrating
              phase)            vapor phase                                                        tanks leaking gasoline, diesel fuel, home
                  Contaminant plume moves     Water well
                                                                                                   heating oil, or toxic solvents.
                  with the groundwater                     Fig. 21-8, p. 502

  Case Study: Arsenic in                                                                                                      Solutions

  Groundwater - a Natural
                                                                                                                     Groundwater Pollution
                                                                                                         Prevention                           Cleanup

  Threat                                                                                              Find substitutes for
                                                                                                      toxic chemicals
                                                                                                                                               Pump to surface,
                                                                                                                                               clean, and return
                                                                                                                                               to aquifer (very
                                                                                                      Keep toxic                               expensive)
                                                                                                      chemicals out of
           Toxic Arsenic (As) can naturally occur at                                                  the environment
           high levels in soil and rocks.                                                             Install monitoring
                                                                                                      wells near landfills
                                                                                                                                               to clean up
                                                                                                      and underground                          contamination
           Drilling into aquifers can release As into                                                 tanks                                    (less expensive
                                                                                                                                               but still costly)
                                                                                                      Require leak detectors
           drinking water supplies.                                                                   on underground tanks
           According to WHO, more than 112 million                                                    Ban hazardous
                                                                                                      waste disposal
                                                                                                                                               nanoparticles of
                                                                                                      in landfills and
           people are drinking water with As levels                                                   injection wells
                                                                                                                                               compounds to
                                                                                                                                               remove pollutants
                                                                                                                                               (may be the
           5-100 times the 10 ppb standard.                                                           Store harmful liquids in                 cheapest, easiest,
                                                                                                      aboveground tanks with leak              and most effective
                 Mostly in Bangladesh, China, and West                                                detection and collection
                                                                                                                                               method but is still
                                                                                                                                               being developed)
                 Bengal, India.                                                                                                                                            Fig. 21-9, p. 504

                                                                               Industry               Cities          Urban sprawl
                                                                               Nitrogen oxides        Toxic metals    Bacteria and              Construction sites
                                                                               from autos and         and oil from    viruses from              Sediments are washed into

                                                                               smokestacks,           streets and     sewers and septic         waterways, choking fish and
                                                                               toxic chemicals,       parking lots    tanks contaminate         plants, clouding waters, and
                                                                               and heavy metals       pollute         shellfish beds            blocking sunlight.
                                                                               in effluents flow      waters;
                                                                               into bays and
                                                                               estuaries.                                                               Farms
                                                                                                                                                        Runoff of pesticides, manure, and
                                                                                                                                                        fertilizers adds toxins and excess
                                                                                                                                                        nitrogen and phosphorus.
           Oceans, if they are not overloaded, can                                                                                                                 Red tides
                                                                                                                                       Closed                      Excess nitrogen causes
           disperse and break down large quantities                                                                                    shellfish beds              explosive growth of
                                                                                                                                                                   toxicmicroscopic algae,
                                                                                                                 Closed                                            poisoning fish and
           of degradable pollutants.                                                                             beach
                                                                                                                                                                   marine mammals.
           Pollution of coastal waters near heavily
           populated areas is a serious problem.
                                                                               Toxic sediments
                 About 40% of the world’s population lives                     Chemicals and toxic
                                                                               metals contaminate
                 near on or near the coast.                                    shellfish beds, kill
                                                                               spawning fish, and
                                                                               accumulate in the
                 The EPA has classified 4 of 5 estuaries as                    tissues of bottom
                                                                                                                          Oxygen-depleted zone               Healthy zone
                 threatened or impaired.                                                                                  Sedimentation and algae
                                                                                                                          overgrowth reduce sunlight,
                                                                                                                                                             Clear, oxygen-rich
                                                                                                                                                             waters promote growth
                                                                                                                          kill beneficial sea grasses, use   of plankton and sea grasses,
                                                                                                                          up oxygen, and degrade habitat.                 fish.
                                                                                                                                                             and support Fig. 21-10, p. 505

OCEAN POLLUTION                                                                    Oxygen Depletion in the
                                                                                   Northern Gulf of Mexico
                                                                                                        A large zone of
                                                                                                        water forms for
                                                                                                        half of the year in
                                                                                                        the Gulf of Mexico
                                                                                                        as a result of
                                                                                                        Resulted from
      Harmful algal blooms (HAB) are caused                                                             cultural
      by explosive growth of harmful algae                                                              agriculture waste,
      from sewage and agricultural runoff.                                                              pesticides and
                                                              Figure 21-11                                                  21-
                                                                                                                     Figure 21-A

                                           Missouri River                          Case Study: The
                                                                                   Chesapeake Bay – An
                     River Basin                                                   Estuary in Trouble
                                                                                                  Pollutants from six states
                                                        Ohio River
                                                                                                  contaminate the shallow estuary,
                                                     Mississippi River                            but cooperative efforts have
                                                                                                  reduced some of the pollution
                                                                                                  Eutrophication due to cultural
                                                                                                  and agricultural pollution.
                MS                                                                                Industries violate discharge
          LA                                                                                      permits)
                                    LOUISIANA        Mississippi
 TX                                                                                               Drop in fishing industry
                                                                                                  especially oysters, clams &
                                   Depleted oxygen                                                crabs.
                                                                                                  Chesapeake Program, 1983.
         Gulf of Mexico                                 Gulf of Mexico
                                                               Fig. 21-A, p. 507                                            21-
                                                                                                                     Figure 21-12

OCEAN OIL POLLUTION                                                                OCEAN OIL POLLUTION

      Most ocean oil pollution comes from                                                             Tanker
      human activities on land.
                          land.                                                                       accidents and
        Studies have shown it takes about 3 years                                                     blowouts at
        for many forms of marine life to recover from                                                 offshore drilling
        large amounts of crude oil (oil directly from                                                 rigs can be
        ground).                                                                                      extremely
        Recovery from exposure to refined oil (fuel                                                   devastating to
                       etc…           10-
        oil, gasoline, etc…) can take 10-20 years for
                                                                                                      marine life
        marine life to recover.
                                                                                                      diving birds, 21-13
                                                                                                                 Figure 21-

                                  Solutions                                               PREVENTING AND
                                                                                          REDUCING SURFACE
                             Coastal Water Pollution
                    Prevention                 Cleanup
Reduce input of toxic pollutants               Improve oil-spill cleanup
                                               capabilities                               WATER POLLUTION
Separate sewage and storm lines

Ban dumping of wastes and
sewage by maritime and cruise                  Sprinkle nanoparticles over an
                                                                                                     The key to reducing nonpoint pollution –
ships in coastal waters                        oil or sewage spill to dissolve
                                               the oil or sewage without
                                                                                                     most of it from agriculture – is to prevent
Ban ocean dumping of sludge and
hazardous dredged material
                                               creating harmful by-products
                                               (still under development)                             it from reaching bodies of water.
                                                                                                          Farmers can reduce runoff by planting
Protect sensitive areas from
development, oil drilling, and                 Require at least secondary                                 buffers and locating feedlots away from
oil shipping                                   treatment of coastal sewage                                steeply sloped land, flood zones, and
Regulate coastal development                                                                              surface water.
Recycle used oil                               Use wetlands, solar-aquatic,
                                               or other methods to treat sewage
Require double hulls for oil tankers
                                                                    Fig. 21-14, p. 509

PREVENTING AND                                                                            Reducing Water Pollution
REDUCING SURFACE                                                                          through Sewage Treatment
         Most developed countries use laws to set
         water pollution standards, but such laws
         rarely exist in developing countries.
             The U.S. Clean Water Act sets standards fro
             allowed levels of key water pollutants and
             requires polluters to get permits.
                                                                                                     Septic tanks and various levels of
             EPA is experimenting with a discharge
             trading policy similar to that for air pollution                                                                       point-
                                                                                                     sewage treatment can reduce point-
             control.                                                                                source water pollution.
                                                                                                                                                                   Figure 21-15

                                                                                         Dust Particles                      Odors
                                                                                         Particles of dried sludge           Odors may cause illness or
                                                                                         carry viruses and harmful           indicate presence of harmful gases.
                                                                                         bacteria that can be
                                                                                         inhaled, infect cuts or enter
            Manhole cover                                                                homes.
            (for cleanout)

                                                               Septic tank                                                  BUFFER           Exposure
                                                                                                                              ZONE           Children may walk or
             Gas                                                Distribution box                                                             play in fertilized fields.
                                                                                                                                             Livestock Poisoning
         Wastewater                                                                                                      Sludge              Cows may die after grazing
                                                                                                                                             on sludge-treated fields.
                                        Drain field                                      Contamination
                                        (gravel or                                       Harmful chemicals               Surface Runoff
                                        crushed stone)                                   and pathogens                   Harmful chemicals
                                                                     Vent pipe           may leach into                  and pathogens may
                                                                                         groundwater                     pollute nearby
                                                              Perforated pipe            and shallow wells.              streams,lakes, ponds,
                                                                                                                         and wetlands.

                                                                    Fig. 21-15, p. 510                                                                             Fig. 21-17, p. 513

Reducing Water Pollution                                  Reducing Water Pollution
through Sewage Treatment                                  through Sewage Treatment

    Sewage sludge can be used as a soil                        Natural and artificial wetlands and other
    conditioner but this can cause health                      ecological systems can be used to treat
    problems if it contains infectious bacteria                sewage.
    and toxic chemicals.                                          California created a 65 hectare wetland near
    Preventing toxic chemicals from reaching                      Humboldt Bay that acts as a natural
    sewage treatment plants would eliminate                       wastewater treatment plant for the town of
                                                                  16,000 people.
    such chemicals from the sludge and
                                                                     The project cost less than half of the estimated
    water discharged from such plants.                               price of a conventional treatment plant.

Pollution from Agriculture                                Industrial Wastes In Water
Fertilizers runoff causing                                Food Processing Factories
                                                            Produce huge amounts of
nutrient enrichment of                                      organic wastes that must
surface waters                                              be treated before
                                                            entering the environment

Soil erosion increases                                    Electronics Producers
sedimentation in surface                                    Often produce waste
                                                            waters with high
waters                                                      levels of heavy metals

Reducing Water Pollution                                  DRINKING WATER
through Sewage Treatment                                  QUALITY
    Water pollution laws have significantly
                                                               Centralized water treatment plants and
    improved water quality in many U.S. streams                watershed protection can provide safe
    and lakes but there is a long way to go.                   drinking water for city dwellers in
    Some want to strengthen the U.S. Clean Water               developed countries.
    Act (CWA) to prevent rather than focusing on               Simpler and cheaper ways can be used
    end- of- the-
    end-of-the-pipe removal.                                   to purify drinking water for developing
    Many farmers and developers see the CWA as                 countries.
    limiting their rights as property owners to fill in                                            sun’
                                                                  Exposing water to heat and the sun’s UV rays for 3
    wetlands.                                                     hours can kill infectious microbes. (This is a cheap
                                                                  way for poor countries to protect themselves
                                                                  against disease – if they are educated!)

                                                             Using Laws to Protect Drinking
Using Laws to Protect                                        Water
Drinking Water                                               The U.N. estimates that 5.6 million
                                                             Americans drink water that does not meet
  While most developed countries have                        EPA standards.
  drinking water quality standards and                       1 in 5 Americans drinks water from a
  laws, most developing countries do not.                    treatment plant that violated one or more
  The U.S Safe Drinking Water Act                            safety standard.
  requires the EPA to establish national                     Industry pressures to weaken the Safe
  drinking water standards (maximum
                            (maximum                         Drinking Act:
  contaminant levels) for any pollutant
                levels)                                        Eliminate national tests and public notification of
  that may have adverse effects on human
                                                               Allow rights to pollute if provider cannot afford to
  health.                                                      comply.

Is Bottled Water the                                        Improving
Answer?                                                     Water
  Some bottled water is not as pure as tap
  water and costs much more.
    1.4 million metric tons of plastic bottles are
    thrown away.
    Fossil fuels are used to make plastic bottles.
      The oil used to produce plastic bottles in the U.S.
      each year would fuel 100,000 cars.

                Waste Water                                 Reducing Water Pollution
                Disposal of Sewage                          through Sewage Treatment
                                                                 Raw sewage reaching a municipal sewage treatment
                                                                 plant typically undergoes:
                                                                    Primary sewage treatment: a physical process that uses
                                  Municipal                         screens and a grit tank to remove large floating objects and
                                                                    allows settling.
                                     Primary                                              treatment:
                                                                    Secondary sewage treatment: a biological process in
                                                                    which aerobic bacteria remove as much as 90% of dissolved
                                     Secondary                      and biodegradable, oxygen demanding organic wastes.
                                     (Tertiary)                     Disinfection (chlorine, ozone, UV)
                                                                    Tertiary Treatment: Chemical process to remove special
                                  Private                           pollutants such as nitrates and phosphates.

                                     Septic tanks

Primary Treatment                                        Primary Sedimentation Tank
Taking out solids
   Grating (removes
   Moving Screen: takes
   out small pieces                                                 Sludge settles
   Grit Tank
   (sand &

Secondary Treatment                                         Water can then be released to river or ocean
Biological Degradation                                      Can be used as industrial coolant water, golf
  Aeration tank (or sewage lagoon)                          courses, parks, etc.
  Fluid is mixed with a bacteria slurry
  Activated Sludge Treatment

Reducing Water Pollution
                                                                                                                                  Sand and
                                                                                                                                  Filtration (clean

through Sewage Treatment                                                Primary                                    Secondary      dirt and odor)

                                                         Bar screen Grit chamber Settling tank   Aeration tank   Settling tank   disinfection tank

                                                                                                                                             To river,
                                                                                    Sludge                                                   or ocean
                                                         Raw sewage                                 Activated sludge      (kills bacteria)
                                                         from sewers

                                                                                                 Air pump

                                                                                                                                      Disposed of
                                                         If water is being released into                                              in landfill or
                                                                                                                                      ocean or
                                                         environment – must be                                                        applied to
                                                         dechlorinated.                                      Sludge drying bed        cropland,
                                                                                                                                      pasture, or
  Primary and Secondary sewage treatment.                                                                                             rangeland

                                          Figure 21-16                                                                                Fig. 21-16, p. 511

Reducing Water Pollution                             Purification of Drinking
through Sewage Treatment                             Water

   Advanced or tertiary sewage treatment:            The Chlorine Dilemma
      Uses series of chemical and physical            Chlorine is added to drinking
      processes to remove specific pollutants left    water to kill pathogens
      (especially nitrates and phosphates).           Chlorine has recently
   Water is chlorinated to remove coloration          been linked to several
                                                      types of cancers
   and to kill disease-carrying bacteria and          (rectal and bladder)
   some viruses (disinfect). (done after
                                                      Left in your tap water.
   secondary or tertiary)

The Chlorine Dilemma                                 Tertiary Treatment
 Problem is there are few                            Removal of plant
 alternatives to chlorine                            nutrients
 EPA has proposed                                      Accomplished by
 reducing the amount of
 chlorine used to treat                                passage through a
 drinking water                                        wetland or lagoon:
 Ozone gas is being                                    DUCKWEED
 developed as an alternative                           sometimes chlorinated
 UV light (expensive to                                as a final measure
 replace bulbs)

                                                     Arcata Marsh and Wildlife Sanctuary
Fluoridation Treating                                Arcata, CA
Small amounts have been
                                                      1986, Wetlands system
added to drinking water since
                                                      Tertiary Treatment
the 1940’s to prevent tooth
                                                      (low tech) to remove
decay                                                 nitrates and
As of 1996, 62% of public                             Recreation (trials,
water supplies have                                   bikes, birding!)
fluoridated water                                     Habitat for birds and
supplies                                              mammals

                                               Problems with Combined
                                               Sewer Overflow
                                                 Human and Industrial wastes are mixed
                                                 with urban runoff before flowing to sewage
                                                 treatment plant

Problems with Combined                          Clean Water Act, 1972
Sewer Overflow                                  amended 1977
                                                  Restore and maintain the chemical, physical
   The Clean Water Act of                         and biological integrity of the nations water.
   1972 banned combined                           1. Make all US Surface waters fishable and
   sewer systems                                  swimmable by 1983
   Required industrial                            2. Requires discharge permits of major
   waste water and human                          polluters
   waste water be in                              3. Identify Toxic pollutants and require the sue
   separate                                       of best practical technology to remove
   pipes                                          pollutants
                                                  4. Set goals for available technology (BAT) to
                                                  be developed in the future

                                               Clean Water Act 1972
 Clean Water Act
                                                 EPA required to set up and monitor the
                                                 MAXIMUM PERMISSIBLE AMOUNTS OF
   Clean Water Act 1972 Protects Water
                                                 POLLUTANTS that can be discharged
   Quality in 3 ways:
                                                 into surface waters from point sources
     Regulate Point Sources of Pollution
       Permits for effluent discharge
                                                 Money to monitor
      Manage watersheds to control urban and     Power to fine
                  run- off(non-
     agricultural run-off(non-point)
      Fund municipal waste treatment

                                                      Safe Drinking Water Act -
Clean Water Acts                                      1974 Maximum Contamination Level
                                                       (MCL’s) for drinking water
                                                       (MCL s) for drinking water
                                                          To set national health-based standards for
                                                          drinking water to protect against both
      Water Quality Act -1987                             naturally-                man-
                                                          naturally-occurring and man-made
                                                          contaminants that may be found in drinking
         Established a national policy for nonpoint       water. US EPA, states, and water systems
         sources of pollution                             then work together to make sure that these
                                                          standards are met.
      Required discharge permits for effluent          to protect drinking water and its sources: rivers,
                                                       lakes, reservoirs, springs, and ground water
      emissions                                        wells. Any area of land that is important either
                                                       as a source of water or a watershed is protected
                                                       from development
                                                       1986 ammendment:
                                                             Requires municipal water sellers to tell
                                                             consumers what contaminates are present
                                                             in city drinking water and associated
                                                             health risks (Corona Consumer Report)

Water Pollution Solutions
Protect Wetlands
                                                      Clean Water Acts
   Protect and Restore
   Wetlands protect water sources by
   taking up toxic pollutants such as heavy              Federal Water Pollution Control Act
   Wetlands uptake excess nutrients such                   Establish controls & regulate discharge
   as nitrate and phosphates that are not                  point sources of pollution (paper, and
   fully removed by water treatment plants
   Provides habitat for birds, mammals                     chemical industries)
   and aquatic life.
                                                           Provide billions of dollars for sewage
Clean Water Act 1972:
                   1972:                                   treatment plants
   If an area of land is classified as a
   wetland or important to the preservation
   of a wetland it is protected from
   “no net loss of wetlands”

Treatment of Human
                                                      Septic Tanks
Sewage treatment works
  Sewage treatment works                                 house- by-
                                                      A house-by-house                   •Works well if maintained, but
  well except:                                        alternative to sewer               can leak into ground water
     Water in storm drains                            systems
     get no treatment (some                           Water is pumped into a
     cities)                                          tank
     During storms, raw                                 Oils rise to top, solids to
     sewage is dumped                                   bottom
     Treated water still has                            Middle water is pumped into
                                                        a series of pipes where it
     environmental effects                              can evaporate and be
                                                        worked on by bacteria

Periods of High Runoff      Water Pollution Solutions
In heavy rains or              Ban or Regulate
snow melt, treatment           Phosphate
plant can’t                    Detergents
handle the excess
                                 Advanced water
                                 treatment to
Untreated water                  remove them
overflows and
spills untreated
into nearby
water ways

Water Pollution Solutions   Water Pollution Solutions
Control Agricultural
                                Control Urban
 Reduce runoff
                                 Golf courses,
 from farms,
                                 lawns, pets
                                 Reduce use
 Reclaim water

Water Pollution Solutions   Water Pollution Solutions

                            Control Streambank
   Control Sediments
   and Acids From
   Mines                      Protect and
     Revegetation and         revegetate
     sediment traps

Great Lakes                                           US-
                                                Joint US-Canadian Management

    Created by retreating                         Since 1972, millions
    glaciers                                      spent to clean up lakes
    1/5 of world’s fresh
                                                  DDT, bacterial &
    SURFACE water
                                                  organic chemical
    33 million people live
                                                  pollution on decline;
    in watershed
                                                  endocrine disruptors,
     Major dumping site
    for toxins                                    heavy metals on the
                                                  Many areas still not
                                                  safe to eat fish

Pollution Indicators                            Some Good News
                                                   Between 1972 and 1992 fishable and
    Eutrophication, hazardous                      swimmable water has increased from
    bacterial levels, fish kills
                                                   36% to 62%
    SERIOUS birth defects in
    almost 50% of animals                          Average phosphorous levels have
    studied                                        dropped from .12ppm to .079ppm
    Exotic species (zebra                          DDT has dropped from 1.2ppm to
    mussels, lampreys)
    wrecking havoc                                 .196ppm


Still Work to Do...                                                 Water Pollution

                                                        • Prevent groundwater contamination
44% of lakes, 37% of rivers and 32% of                  • Reduce nonpoint runoff
estuaries are unsafe for fishing and swimming           • 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 air pollution
                                                        • Reduce poverty

                                                        • Reduce birth rates

                                                                                                       Fig. 21-18, p. 517

                    What Can You Do?

                                                                                    Updates Online
                      Water Pollution

• Fertilize garden and yard plants with manure or
  compost instead of commercial inorganic fertilizer.

• Minimize your use of pesticides.                                                    The latest references for topics covered in this section can be
                                                                                                                                            book’ e-
                                                                                      found at the book companion website. Log in to the book’s e-
• Do not apply fertilizer or pesticides near a body of water.
                                                                                      resources page at www.thomsonedu.com to access InfoTrac
• Grow or buy organic foods.                                                          articles.

• Do not drink bottled water unless tests show that your
  tap water is contaminated. Merely refill and reuse                                  InfoTrac:
                                                                                      InfoTrac: Cleaning Up an Effluent Society. Business Week
  plastic bottles with tap water.                                                     Online,
                                                                                      Online, March 22, 2006.
• Compost your food wastes.                                                           InfoTrac:
                                                                                      InfoTrac: Nuclear Reactors Found to Be Leaking
                                                                                      Radioactive Water. Matthew L. Wald. The New York Times,
• Do not use water fresheners in toilets.
                                                                                      March 17, 2006 pA21(L).
• Do not flush unwanted medicines down the toilet.                                    InfoTrac:
                                                                                      InfoTrac: Water and farms: towards sustainable use. Kevin
• Do not pour pesticides, paints, solvents, oil, antifreeze,
                                                                                      Parris, Wilfrid Legg. OECD Observer, March 2006 i254
  or other products containing harmful chemicals down                                 p14(3).
  the drain or onto the ground.                                Fig. 21-19, p. 517     WHO: Arsenic in Drinking Water