Water Reuse:

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Water Reuse A Global View
Rosario Sanchez April 2007 WMHS 602
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Water Scarcity
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Water Scarcity Mostly Developing Nations
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2 Main Drivers Population and Urbanization

• Globally, it is estimated that by 2024, we will
  use 40 more water than we do now.
• Population in 2002 6.2 billion
• Population in 2050 7.9 and 10.3 billion
• (90 in the developing world)
• Developed urbanization under 1 year
• Developing countries over 2 year
• Asia and Africa will have more urban dwellers
  than any other continent.
• Asia will contain 54 of the worlds urban
  population by 2030.

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2 Drivers Population and Urbanization
Growth in urban water supply coverage by world
region
Water Reuse A Global View

• 13 of 15 largest megalopolises are in less
  developed countries.
• 46 of world population already live in cities.
• Developing countries 42
• Developed countries 75.

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2 Drivers Population and Urbanization
Population of the six most populous countries in
Latin America and the Caribbean (millions)
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Other Drivers

• Very low amounts of rainfall and high evaporation
  (Australia 10).
• Large freshwater demand (Japan 71 of domestic
  wastewater is reused).
• Environmental and economic considerations
  (Germany and France).

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Main Use Irrigation

• Of the worlds total arable land, 17 is
  irrigated and produces 34 of the crops.
• Three quarters of the irrigated area (192 mill
  hec) is located in developing countries.
• The use of wastewater represents around 10 of
  the total irrigated surface worldwide.
• One-tenth or more of the worlds population
  consumes crops irrigated with wastewater.
• Vietnam 80 of vegetables vs
• Israel 70 of wastewater is used for nonfood
  crops.
• Reuse in developing countriesjust happens vs in
  developed is part of a strategy.

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Main Use Irrigation
Freshwater Withdrawals for Agricultural Use, 2000
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Source World Resources Institute 2000.
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Wastewater Reuse

• Level of wastewater treatment
• 35 Asia
• 14 Latin America and the Caribbean
• 0 Africa

• There are over 3300 reuse projects
  internationally with approximately 700 in Europe.
  
• The growth in the flow rate capacity each year
  is 25 to 60 in the developed world.
• Many developing countries have adopted an
  approach of the (WHO) lower technology levels
  and costs while addressing the health risk.
• Not enough data lack of national analysis
  political risk.

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Estimated volumes of wastewater (million m3/year)
in Asia
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China 1,330,000
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Wastewater Reuse

• Relative to the amount spent on water services,
  wastewater treatment has received only 15 of
  the total lending in the sector of the World Bank
  over the past 30 years.
• Sanitation coverage in developing countries
  (49) is half that of the developed world (98).

Water Reuse A Global View

• Conventional approaches to wastewater disposal
  in developing countries have taken two forms
• capital-intensive replicas of systems favoured
  in the industrial countries
• primitive variants of open sewers and cesspits.

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Wastewater Reuse Developed
Artificial lakes in Arizona
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And in Florida
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Wastewater Reuse Developing
India
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Pakistan
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Urban Agriculture An Option

• In areas where wastewater is an important
  production factor, people use up to 50-80 of
  their income in food
• The mean annual net income per farmer varies
  from 155 in Yaounde, Cameroon, to 2,800 in
  Hyderabad, India.
• Wastewater market in el Mezquital Valley in
  Mexico, made land rents increase from 171 to
  351.
• Besides yield increases, enables three crops to
  be harvested per year.

Poor cities
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Advantages

• Food security
• Groundwater recharge
• Lima, Peru
• Wagi Dhuleil, Jordan
• Mezquital Valley, Mexico
• Leon, Mexico
• Hay Yai, Tailand

Water Reuse A Global View

• At least, 1,000 mm/y aquifers are recharged
  (some exceeds local precipitation).
• Infiltration is equivalent to 50-70 of the
  water used for agriculture.

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Advantages

• Proximity and dependability
• Competing demands for water resources
• Environmental and economic impacts of
  traditional water resources approaches.
• Proven track record
• Amore accurate cost of water
• More stringent water quality standards (more
  safety?)
• Necessity and opportunity

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Criteria for Using Wastewater (developed)
Criteria to be considered for selecting crops for
a reuse practice (after Grattan and Rhoades 1990)

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Disadvantages

• Viruses and bacteria (mainly primary treatment
  on developing countries)
• Cadmium, lead and mercury
• Nitrates
• Infrastructure costs (euthropication)
• Rights vs. health risks (Pakistan case)
• For most communities, food security and
  nutrition are more important than infectious
  disease transmission.

Water Reuse A Global View

• Unplanned indirect potable reuse (de facto
  indirect potable reuse)

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Chemicals of potential health concern in
untreated municipal wastewater

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Disadvantages

• Groundwater recharge
• current surface water withdrawals may or may not
  have an impact on future use, but groundwater
  withdrawals frequently do.
• Once groundwater has become contaminated, the
  prospects for remediation are uncertain and
  expensive.
• Leakage around 30 of domestic water supply.
• Mexico City the quantity of water looses is
  enough to meet the needs of a city the size of
  Rome.

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Challenges

• Institutional/social, economical/technical
  issues.
• New approach includes sustainability,
  environmental ethics and public participation.
• Local scale instead of large scalebut
• Effective water resource management requires a
  holistic approach that considers an entire
  watershed or catchment are relative to water
  quantity, quality and use.
• Local engagement is not sufficient, government
  need to compromise.

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Challenges

• For a system to be sustainable, all stakeholders
  must believe that their needs are being met
  satisfactorily.
• Success in wastewater projects proved to be
  decisively influenced by local circumstance and
  experience
• With few exceptions, developing countries are
  climate taker, not climate makers. They must
  react defensively.
• Highly engineered systems are not economically
  efficient.

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Decentralization
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Tips

• Focus on water demand management..
• Processes and innovation should be shared, not
  the product.
• New is not always better
• Understand local life..
• Evaluation and observation.
• Goals efficiency, equity and environmental
  sustainability.

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References

• Biswas, Asit K. Water Management in Latin America
  and the Caribbean. Water Resources Development,
  Vol. 14, No. 3, 293-303, 1998.
• Junyin chu, Jining Chen, Can Wang, Ping Fu.
  Wastewater reuse potential analysis implications
  for Chinas water resources management. Water
  Research 38, 2746-2756, 2004.
• Asano, Takashi, Cotruvo, Joseph A. Groundwater
  recharge with reclaimed municipal wastewater
  health and regulatory considerations. Water
  Research 38, 1941-1951, 2004.
• Gaulke, Linda. On site wastewater treatment and
  reuses in Japan. Water Management, 159, 2,
  103-109, 2006.
• Gleick, Peter H. Making Every Drop Count.
  Scientific American. 284, 2, 2001.
• Jimenez, Blanca. Irrigation in Developing
  Countries Using Wastewater. International Review
  for Environmental Strategies, Vol 6, No 2.
  229-250, 2006.
• Okun, Daniel A. Water Reclamation and
  Unrestricted Nonpotable Reuse A New Tool in
  Urban Water Management. Public Health, 21,
  223-45, 2000.
• Asano, Takashi et, al. Water Reuse Issues,
  Technologies and Applications. Metcalf and Eddy,
  2006.
• Meeting the Challenges of Megacities in the
  Developing World A collection of Working Papers,
  Office of International Affairs, The National
  Academy Press, 1996.
• World Water Day Water and Culture
• Facts and Figures extracted from the 2nd United
  Nations World Water Development Report, 2006.
• -USAID. Com

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Questions?