Water Resources and Water Pollution

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Water Resources and Water Pollution

• Chapter 8

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8-1 Will We Have Enough Usable Water?

• Concept 8-1A We are using available freshwater
  unsustainably by wasting it, polluting it, and
  charging too little for this irreplaceable
  natural resource.
• Concept 8-1B One of every six people does not
  have sufficient access to clean water, and this
  situation will almost certainly get worse.

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Freshwater Is an Irreplaceable Resource That We
Are Managing Poorly (1)

• Why is water so important?
• Earth as a watery world 71
• Freshwater availability 0.024
• Poorly managed resource
• Hydrologic cycle
• Water pollution

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Freshwater Is an Irreplaceable Resource That We
Are Managing Poorly (2)

• Hydrologic cycle
• Movement of water in the seas, land, and air
• Driven by solar energy and gravity
• People divided into
• Water haves
• Water have-nots

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We Get Freshwater from Groundwater and Surface
Water (1)

• Ground water
• Zone of saturation
• Water table
• Aquifers
• Natural recharge
• Lateral recharge

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We Get Freshwater from Groundwater and Surface
Water (2)

• Surface Water
• Surface runoff
• Watershed (drainage) basin
• Reliable runoff
• 1/3 of total

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We Use More than Half of the Worlds Reliable
Runoff

• 2/3 of the surface runoff lost by seasonal
  floods
• 1/3 runoff usable
• Domestic 10
• Agriculture 70
• Industrial use 20
• Fred Pearce, author of When the Rivers Run Dry

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Case Study Freshwater Resources in the United
States

• More than enough renewable freshwater, unevenly
  distributed
• Effect of
• Floods
• Pollution
• Drought
• 2007 U.S. Geological Survey projection
• Water hotspots

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Water Shortages Will Grow (1)

• Dry climate
• Drought
• Too many people using a normal supply of water

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Water Shortages Will Grow (2)

• Wasteful use of water
• China and urbanization
• Hydrological poverty

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Core Case Study Water Conflicts in the Middle
East A Preview of the Future

• Water shortages in the Middle East hydrological
  poverty
• Nile River
• Jordan Basin
• Tigris and Euphrates Rivers
• Peacefully solving the problems

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8-2 How Can We Increase Water Supplies?

• Concept 8-2 Pumping groundwater, building dams,
  transferring water, and desalination can all
  increase water supplies, but these strategies all
  create environmental problems.

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Groundwater Is Being Withdrawn Faster Than It Is
Replenished in Some Areas (1)

• India, China, and the United States
• Three largest grain producers
• Overpumping aquifers for irrigation of crops
• India and China
• Small farmers drilling tubewells
• Effect on water table
• Saudi Arabia
• Aquifer depletion and irrigation

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Groundwater Is Being Withdrawn Faster Than It Is
Replenished in Some Areas (2)

• Ogallala aquifer largest known aquifer
• Irrigates the Great Plains
• Water table lowered more than 30m
• Cost of high pumping has eliminated some of the
  farmers
• Government subsidies to continue farming deplete
  the aquifer further
• Biodiversity threatened in some areas
• California Central Valley serious water
  depletion

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Groundwater Is Being Withdrawn Faster Than It Is
Replenished in Some Areas (3)

• Limits future food production
• Bigger gap between the rich and the poor
• Land subsidence
• Mexico City
• Sinkholes

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Groundwater Is Being Withdrawn Faster Than It Is
Replenished in Some Areas (4)

• Groundwater overdrafts near coastal regions
• Contamination of the groundwater with saltwater
• Undrinkable and unusable for irrigation

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Groundwater Is Being Withdrawn Faster Than It Is
Replenished in Some Areas (5)

• Locate the deep aquifers determine if they
  contain freshwater or saline water
• Major concerns
• Geological and ecological impact of pumping water
  from them
• Flow beneath more than one country
• Who has rights to it?

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Large Dams and Reservoirs Have Advantages and
Disadvantages (1)

• Main goals of a dam and reservoir system
• Capture and store runoff
• Release runoff as needed to control
• Floods
• Generate electricity
• Supply irrigation water
• Recreation (reservoirs)

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Large Dams and Reservoirs Have Advantages and
Disadvantages (2)

• Advantages
• Increase the reliable runoff available
• Reduce flooding
• Grow crops in arid regions

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Large Dams and Reservoirs Have Advantages and
Disadvantages (3)

• Disadvantages
• Displaces people
• Flooded regions
• Impaired ecological services of rivers
• Loss of plant and animal species
• Fill up with sediment within 50 years

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We Can Transfer Water from Water-Rich Areas to
Water-Poor Areas

• Water transferred by
• Tunnels
• Aqueducts
• Underground pipes
• May cause environmental problems
• California Water Project

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Case Study The Aral Sea Disaster (1)

• Large-scale water transfers in dry central Asia
• Salinity
• Wetland destruction and wildlife
• Fish extinctions and fishing

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Case Study The Aral Sea Disaster (2)

• Wind-blown salt
• Water pollution
• Climatic changes
• Restoration efforts

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Removing Salt from Seawater (1)

• Desalination
• Distillation
• Reverse osmosis, microfiltration
• 15,000 plants in 125 countries
• Saudi Arabia highest number

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Removing Salt from Seawater (2)

• Problems
• High cost and energy footprint
• Keeps down algal growth and kills many marine
  organisms
• Large quantity of brine wastes
• Future economics

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Science Focus The Search for Improved
Desalination Technology

• Desalination on offshore ships
• Solar or wind energy
• Better membranes
• Better disposal options for the brine waste
• Reduce water needs, conserve water

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8-3 How Can We Use Water More Sustainably?

• Concept 8-3 We can use water more sustainably if
  we cut water waste, raise water prices, slow
  population growth, and protect aquifers, forests,
  and other ecosystems that store and release water.

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Reducing Water Waste Has Many Benefits (1)

• Water conservation
• Improves irrigation efficiency
• Improves collection efficiency
• Uses less in homes and businesses

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Reducing Water Waste Has Many Benefits (2)

• Worldwide 6570 loss
• Evaporation, leaks, etc.
• Water prices low cost to user
• Government subsidies more needed?

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We Can Cut Water Waste in Irrigation (1)

• Flood irrigation
• Wasteful
• Center pivot, low pressure sprinkler
• Low-energy, precision application sprinklers
• Drip or trickle irrigation, microirrigation
• Costly less water waste

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We Can Cut Water Waste in Irrigation (2)

• Human-powered treadle pumps
• Harvest and store rainwater
• Create a canopy over crops reduces evaporation
• Fog-catcher nets

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We Can Cut Water Waste in Industry and Homes (1)

• Recycle water in industry
• Fix leaks in the plumbing systems
• Use water-thrifty landscaping xeriscaping
• Use gray water
• Pay-as-you-go water use

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We Can Cut Water Waste in Industry and Homes (2)

• Can we mimic how nature deals with waste?
• Waterless composting toilets

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We Need to Use Water More Sustainably

• The frog does not drink up the pond in which it
  lives
• Blue revolution

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8-4 How Can We Reduce the Threat of Flooding?

• Concept 8-4 We can improve flood control by
  protecting wetlands and natural vegetation in
  watersheds and by not building in areas subject
  to frequent flooding.

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Some Areas Get Too Much Water from Flooding (1)

• Flood plains
• Highly productive wetlands
• Provide natural flood and erosion control
• Maintain high water quality
• Recharge groundwater
• Benefits of floodplains
• Fertile soils
• Nearby rivers for use and recreation
• Flatlands for urbanization and farming

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Some Areas Get Too Much Water from Flooding (2)

• Dangers of floodplains and floods
• Deadly and destructive
• Human activities worsen floods
• Failing dams and water diversion
• Hurricane Katrina and the Gulf Coast
• Removal of coastal wetlands

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Case Study Living Dangerously on Floodplains in
Bangladesh

• Dense population
• Located on coastal floodplain
• Moderate floods maintain fertile soil
• Increased frequency of large floods
• Effects of development in the Himalayan foothills
• Destruction of coastal wetlands

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We Can Reduce Flood Risks

• Rely more on natures systems
• Wetlands
• Natural vegetation in watersheds
• Rely less on engineering devices
• Dams
• Levees

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8-5 What Are the Causes and Effects of Water
Pollution?

• Concept 8-5 Water pollution, caused mostly by
  agricultural activities, industrial facilities,
  and mining, and worsened by growth in population
  and resource use, causes illness and death in
  humans and other species and disrupts ecosystems.

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Water Pollution Comes from Point and Nonpoint
Sources (1)

• Water pollution
• Point sources
• Located at specific places
• Easy to identify, monitor, and regulate
• Examples

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Water Pollution Comes from Point and Nonpoint
Sources (2)

• Nonpoint sources
• Broad, diffuse areas
• Difficult to identify and control
• Expensive to clean up
• Examples

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Water Pollution Comes from Point and Nonpoint
Sources (3)

• Agriculture activities leading cause of water
  pollution
• Sediment eroded from the lands
• Fertilizers and pesticides
• Bacteria from livestock and food processing
  wastes
• Industrial facilities
• Mining

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Water Pollution Comes from Point and Nonpoint
Sources (4)

• Other sources of water pollution
• Parking lots
• Human-made materials
• E.g., plastics
• Climate change due to global warming

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Major Water Pollutants Have Harmful Effects

• Infectious disease organisms contaminated
  drinking water
• The World Health Organization (WHO)
• 3 Million people die every year, mostly under the
  age of 5

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8-6 What Are the Major Water Pollution Problems
in Streams and Lakes?

• Concept 8-6 Addition of pollutants and excessive
  nutrients to streams and lakes can disrupt these
  ecosystems, and prevention of such pollution is
  more effective and less costly than cleaning it
  up.

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Streams Can Cleanse Themselves If We Do Not
Overload Them

• Dilution
• Biodegradation of wastes by bacteria takes time
• Oxygen sag curve

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Stream Pollution in Developed Countries

• 1970s Water pollution control laws
• Successful water clean-up stories
• Ohio Cuyahoga River, U.S.
• Thames River, Great Britain
• Contamination of toxic inorganic and organic
  chemicals by industries and mines

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Global Outlook Stream Pollution in Developing
Countries

• Half of the worlds 500 rivers are polluted
• Untreated sewage
• Industrial waste
• Indias rivers
• Chinas rivers

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Low Water Flow and Too Little Mixing Makes Lakes
Vulnerable to Water Pollution

• Less effective at diluting pollutants than
  streams
• Stratified layers
• Little vertical mixing
• Little of no water flow

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Cultural Eutrophication Is Too Much of a Good
Thing (1)

• Eutrophication
• Oligotrophic lake
• Low nutrients, clear water
• Cultural eutrophication

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Cultural Eutrophication Is Too Much of a Good
Thing (2)

• During hot weather or droughts
• Algal blooms
• Increased bacteria
• More nutrients
• Anaerobic bacteria
• Then what?

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Cultural Eutrophication Is Too Much of a Good
Thing (3)

• Prevent or reduce cultural eutrophication
• Remove nitrates and phosphates
• Diversion of lake water
• Clean up lakes
• Remove excess weeds
• Use herbicides and algaecides down-side?
• Pump in air

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Case Study Pollution in the Great Lakes (1)

• 1960s Many areas with cultural eutrophication
• 1972 Canada and the United States Great Lakes
  pollution control program
• What was done?
• Problems still exist
• Raw sewage
• Nonpoint runoff of pesticides and fertilizers
• Biological pollution
• Atmospheric deposition of pesticides and Hg

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Case Study Pollution in the Great Lakes (2)

• 2007 State of the Great Lakes report
• New pollutants found
• Wetland loss and degradation significance?
• Declining of some native species
• Native carnivorous fish species declining
• What should be done?

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8-7 What Are the Major Pollution Problems
Affecting Water Sources?

• Concept 8-7 Chemicals used in agriculture,
  industry, transportation, and homes can spill and
  leak into groundwater and make it undrinkable
  polluted water can be purified, but protecting it
  through pollution prevention is the least
  expensive and most effective strategy.

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Ground Water Cannot Cleanse Itself Very Well (1)

• Source of drinking water
• Common pollutants
• Fertilizers and pesticides
• Gasoline
• Organic solvents
• Pollutants dispersed in a widening plume

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Ground Water Cannot Cleanse Itself Very Well (2)

• Slower chemical reactions in groundwater due to
• Slow flow contaminants not diluted
• Less dissolved oxygen
• Fewer decomposing bacteria
• How long will it take to cleans itself of
• Slowly degradable wastes
• E.g., DDT
• Nondegradable wastes
• E.g., Pb and As

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Groundwater Pollution Is a Serious Threat

• China many contaminated or overexploited
  aquifers
• U.S. FDA reports of toxins found in many
  aquifers
• What about leaking underground storage tanks
• Gasoline
• Oil
• Methyl tertiary butyl ether (MTBE)
• Nitrate ions

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Pollution Prevention Is the Only Effective Way to
Protect Groundwater

• Prevent contamination of groundwater
• Cleanup expensive and time consuming

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There Are Many Ways to Purify Drinking Water

• Reservoirs and purification plants
• Process sewer water to drinking water
• Expose clear plastic containers to sunlight (UV)
• Nanofilters
• The LifeStraw

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Is Bottled Water the Answer?

• U.S. some of the cleanest drinking water
• Bottled water
• Some from tap water
• 40 bacterial contamination
• Fuel cost to manufacture the plastic bottles
• Recycling of the plastic
• Growing back-to-the-tap movement

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8-8 What Are the Major Water Pollution Problems
Affecting Oceans?

• Concept 8-8 The great majority of ocean
  pollution originates on land and includes oil and
  other toxic chemicals and solid waste, which
  threaten fish and wildlife and disrupt marine
  ecosystems the key to protecting oceans is to
  reduce the flow of pollutants into coastal
  waters.

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Ocean Pollution Is a Growing and Poorly
Understood Problem (1)

• 2006 State of the Marine Environment
• 80 of marine pollution originates on land
• Sewage
• Coastal areas most affected
• Deeper ocean waters
• Dilution
• Dispersion
• Degradation

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Ocean Pollution Is a Growing and Poorly
Understood Problem (2)

• Cruise line pollution what is being dumped?
• U.S. coastal waters
• Raw sewage
• Sewage and agricultural runoff NO3- and PO43-
• Harmful algal blooms
• Oxygen-depleted zones

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Case Study The Chesapeake Bayan Estuary in
Trouble (1)

• Largest estuary in the US polluted since 1960
• Population increased
• Point and nonpoint sources raised pollution
• Phosphate and nitrate levels too high

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Case Study The Chesapeake Bayan Estuary in
Trouble (2)

• Overfishing
• 1983 Chesapeake Bay Program
• Update on recovery of the Bay
• Should we introduce an Asian oyster?

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Ocean Oil Pollution Is a Serious Problem (1)

• Crude and refined petroleum
• Highly disruptive pollutants
• Largest source of ocean oil pollution
• Urban and industrial runoff from land
• 1989 Exxon Valdez, oil tanker
• 2002 Prestige, oil tanker

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Ocean Oil Pollution Is a Serious Problem (2)

• Volatile organic hydrocarbons
• Kill many aquatic organisms
• Tar-like globs on the oceans surface
• Coat animals
• Heavy oil components sink
• Affect the bottom dwellers

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Ocean Oil Pollution Is a Serious Problem (3)

• Faster recovery from crude oil than refined oil
• Cleanup procedures
• Methods of preventing oil spills

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8-9 How Can We Best Deal with Water Pollution?

• Concept 8-9 Reducing water pollution requires
  preventing it, working with nature in treating
  sewage, cutting resource use and waste, reducing
  poverty, and slowing population growth.

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We Need to Reduce Surface Water Pollution from
Nonpoint Sources (1)

• Reduce erosion
• Keep cropland covered with vegetation
• Reduce the amount of fertilizers
• Plant buffer zones of vegetation
• Use organic farming techniques

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We Need to Reduce Surface Water Pollution from
Nonpoint Sources (2)

• Use pesticides prudently
• Control runoff
• Tougher pollution regulations for livestock
  operations
• Deal better with animal waste

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Laws Can Help Reduce Water Pollution from Point
Sources

• 1972 Clean Water Act
• EPA experimenting with a discharge trading
  policy
• Could this allow pollutants to build up?

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Case Study U.S. Experience with Reducing
Point-Source Pollution (1)

• Numerous improvements in water quality
• Some lakes and streams are not safe for swimming
  or fishing
• Treated wastewater still produces algal blooms
• High levels of Hg, pesticides, and other toxic
  materials in fish

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Case Study U.S. Experience with Reducing
Point-Source Pollution (2)

• Leakage of gasoline storage tanks into
  groundwater
• Weaken or strengthen the Clean Water Act

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Sewage Treatment Reduces Water Pollution (1)

• Septic tank system
• Wastewater or sewage treatment plants
• Primary sewage treatment
• Physical process
• Secondary sewage treatment
• Biological process
• Tertiary or advance sewage treatment
• Bleaching, chlorination

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Sewage Treatment Reduces Water Pollution (2)

• Should there be separate pipes for sewage and
  storm runoff?
• Health risks of swimming in water with blended
  sewage wastes

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We Can Improve Conventional Sewage Treatment

• Peter Montague environmental scientist
• Remove toxic wastes before water goes to the
  municipal sewage treatment plants
• Reduce or eliminate use and waste of toxic
  chemicals
• Use composting toilet systems
• Wetland-based sewage treatment systems

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Science Focus Treating Sewage by Working with
Nature

• John Todd biologist
• Natural water purification system
• Sewer water flows into a passive greenhouse
• Solar energy and natural processes remove and
  recycle nutrients
• Diversity of organisms used

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There Are Sustainable Ways to Reduce and Prevent
Water Pollution

• Developed countries
• Bottom-up political pressure to pass laws
• Developing countries
• Little to reduce water pollution
• China ambitious plan