World Water Crisis

1
World Water Crisis Water, water everywhere
but whats a brother gotta do to get a drink
around here?

• Joel Thomas
• CBE 555
• November 27, 2007
• Updated Joel Thomas (F07)
• Original Christie Dosch (F05)

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Contents of the Crisis

• Availability/Safety
• Sanitation
• Desalination
• Other factors
• Contamination

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Availability/Safety
4
Water Breakdown

• 70 of Earth is H2O
• 3 of H2O is freshwater
• Of freshwater
• 79 is glacial
• 20 is groundwater
• 1 is surface water
• Of surface water
• 52 is lakes
• 38 is soil Moisture
• 8 is atmospheric vapor
• 1 in living organisms
• 1 is rivers

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Percent of Population with Access to Safe
Drinking Water by Country, 2000
6
Percent of Total Disease Burden Caused by Unsafe
Water by Country, 2000
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Renewable Freshwater Supply by Country, 2000
m3 per person per year
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Scarcity

• Middle East
• Many of the wars of this 20th century were
  about oil, but the wars of the next century will
  be about water - World Bank Vice President
  Ismail Serageldin
• Hebron, Palestine limited households to running
  water twice a month
• Egypt will require an extra 20 million m3 to meet
  the needs of the growing population

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Quality

• Only 60 of population of Africa has access to
  safe drinking water
• In largest cities, lt 10 have sewer connections
• Increased preference for/reliance on well water
• 2.3 billion people world wide suffer from
  diseases linked to dirty water
• Contaminations
• Biological Poor Sanitation
• Chemical/Mineral Further Study of Arsenic in
  Bangladesh

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Treatment
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Sewage Treatment
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Sewage Treatment

• Preliminary
• Filter/screen to remove solids and grit
• Solids and grit are washed and land-filled

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Sewage Treatment
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Sewage Treatment

• Primary
• Settling tanks (clarifiers) to remove remaining
  solids
• Produces sludge containing 70 of initial
  solids
• Sludge treated by digestion
• Heat bacteria to optimal conditions
• Produces methane
• May be used as fuel
• Remaining solids are cooled and used as
  fertilizer

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Sewage Treatment
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Sewage Treatment

• Secondary
• Percolating filters
• Aeration tanks
• Biological waste from either treatment is settled
  out

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Sewage Treatment
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Sewage Treatment

• Tertiary
• Kill bacteria
• Disinfect using chlorine/bleach
• Dechlorinate using sodium bisulfite or similar
  compound
• Reed beds, sand filters, grass plots
• UV light

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Assessing Potability

• Biochemical Oxygen Demand (BOD)
• Amount of O2 required by bacteria to oxidize
  organic material in 5 days
• Drinking water lt 1ppm
• Raw sewage gtgt 100ppm

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Desalination
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Desalination

• 7500 plants world wide
• 60 in Middle East
• Saudi Arabia produces 128 million gallons per day
• 12 in Americas
• Florida and Caribbean

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Desalination Process

• Requires pre-treatment
• Chlorination
• Ozone
• UV light
• Stripping or scrubbing to remove Cl or O3

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Desalination Processes

• 1-50 ppm solids
• Phase separation
• Multiple Effect Distillation
• Sometimes paired with membrane
• Multiple Stage Flash
• Flash at successively lower pressures
• Mechanical Vapor Compression

• Higher Concentrations
• Mechanical separation
• Reverse Osmosis
• Electrodialysis Reversal
• 98 salt removal
• Used if 2 of initial salt content allowable
• Otherwise, further separation required

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Desalination Efficiency

• City of Santa Barbara Desalination Plant
• 8.2 MGD of brine
• At 1.8 X the Salinity of Seawater
• 6.7 MGD product
• 1.7 MGD filter brine
• 1.7-5.1 cubic yards/day of solids
• 40 percent water recovery!!!

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Why arent these used in Africa?

• Lack of education
• Lack of technology
• Lack of stable government
• Lack of funds

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Other Factors

• Pollution
• Water contaminated with toxic materials
• Acid rain
• Eutrophication disrupts ecosystem
• E.g. Phosphorus, Nitrogen from fertilizer
• Global warming
• Redistribution of water
• Glaciers melting
• Aquifers depleting

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Contamination
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Source of Contaminants

• Underground injections wells
• Landfills
• Runoff from roads/agriculture
• Leaks/spills in chemical storage or
  transportation (including septic, petroleum)
• 1 L of gas contaminates 1 Million L of groundwater

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Arsenic Contamination

• India
• Bengal and Bangladesh (Ganges River area)
• As high as 1.8ppm (EPA limit is 10ppb)
• 200,000 people dead from As poisoning

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Arsenic Decontamination

• Removal
• Adsorption with ferric oxide compound
• ppt with iron salts
• Nanofiltration
• MnO2
• Coagulation

• Problems
• Removal is expensive
• Detection is difficult
• Field tests only detect above 0.05mg/L (the upper
  limit)
• Technology is not readily available
• Expensive Equipment
• Extensive Training

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References

• http//www.world-wide-water.com/ - water
  treatment technical info/guide
• http//www.who.int/mediacentre/factsheets/fs210/en
  / - World Health Org. Bangladesh info
• http//www.wateryear2003.org/en/ev.php-URL_ID4874
  URL_DODO_TOPICURL_SECTION201.html African
  Situation
• http//www.umich.edu/gs265/society/waterpollution
  .htm - water distribution, usage, pollution
• http//ohioline.osu.edu/aex-fact/0768.html -
  treatment principles, regulations, diagram
• http//users.rcn.com/jkimball.ma.ultranet/BiologyP
  ages/S/SewageTreatment.html -Sewage treatment
  principles
• http//www.coastal.ca.gov/desalrpt/dchap1.html -
  Seawater Desalination
• http//www.nature.com/nature/focus/water/index.htm
  l - Global Water Crisis Articles
• http//news.nationalgeographic.com/news/2000/07/07
  14_water.html - Water and Peace in the Middle
  East
• http//answers.google.com/answers/threadview?id34
  014 Further Resources for Desalination
  (specifically charitable)
• http//www.mwra.state.ma.us/03sewer/html/sewditp.h
  tm - Detailed WW Treatment

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Seawater Composition Seawater Composition

Element by mass Component molality (mol/kg)
O 85.84 H2O 53.6
H 10.82 Cl- 0.546
Cl 1.94 Na 0.469
Na 1.08 Mg2 0.0528
Mg 0.1292 SO4,2- 0.0282
S 0.091 Ca2 0.0103
Ca 0.04 K 0.0102
K 0.04 C inorganic 0.00206
Br 0.0067 Br- 0.000844
C 0.0028 B total 0.000416
Au less Sr2 0.000091
    F- 0.000068