World Water Crisis Water water everywhere but whats

World Water Crisis ” ‘Water, water everywhere’ but what’s a brother gotta do to get a drink around here? ” Joel Thomas CBE 555 November 27, 2007 Updated: Joel Thomas (F 07) Original: Christie Dosch (F 05)

Contents of the Crisis • Availability/Safety • Sanitation • Desalination • Other factors – Contamination

Availability/Safety

Water Breakdown • • • 70% of Earth is H 2 O 3% of H 2 O is freshwater Of freshwater – – – 79% is glacial 20% is groundwater 1% is surface water – – – 52% is lakes 38% is soil Moisture 8% is atmospheric vapor 1% in living organisms 1% is rivers • Of surface water

Percent of Population with Access to Safe Drinking Water by Country, 2000

Percent of Total Disease Burden Caused by Unsafe Water by Country, 2000

Renewable Freshwater Supply by Country*, 2000 *m 3 person per year

Scarcity • Middle East – “Many of the wars of this [20 th] 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 m 3 to meet the needs of the growing population

Quality • Only 60% of population of Africa has access to safe drinking water – In largest cities, < 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

Treatment

Sewage Treatment

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

Sewage Treatment

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 v May be used as fuel – Remaining solids are cooled and used as fertilizer

Sewage Treatment

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

Sewage Treatment

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

Assessing Potability • Biochemical Oxygen Demand (BOD) – Amount of O 2 required by bacteria to oxidize organic material in 5 days – Drinking water < 1 ppm – Raw sewage >> 100 ppm

Desalination

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

Desalination Process • Requires pre-treatment – Chlorination – Ozone – UV light – Stripping or scrubbing to remove Cl or O 3

Desalination Processes • 1 -50 ppm solids • Phase separation • Higher Concentrations • Mechanical separation – Multiple Effect Distillation – Reverse Osmosis – Electrodialysis Reversal • Sometimes paired with membrane – Multiple Stage Flash • Flash at successively lower • ~98% salt removal • Used if ~2% of initial salt pressures – Mechanical Vapor Compression • content allowable Otherwise, further separation required

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!!!

Why aren’t these used in Africa? • Lack of education • Lack of technology • Lack of stable government • Lack of funds

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

Contamination

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

Arsenic Contamination • India – Bengal and Bangladesh (Ganges River area) – As high as 1. 8 ppm (EPA limit is 10 ppb) – ~200, 000 people dead from As poisoning

Arsenic Decontamination • Removal – Adsorption with ferric oxide compound – ppt with iron salts – Nanofiltration – Mn. O 2 – Coagulation • Problems – Removal is expensive – Detection is difficult • Field tests only detect above 0. 05 mg/L (the upper limit) – Technology is not readily available • Expensive Equipment • Extensive Training

References • http: //www. world-wide-water. com/ - water treatment technical info/guide • http: //www. who. int/mediacentre/factsheets/fs 210/en/ - World Health Org. ; • • • Bangladesh info http: //www. wateryear 2003. org/en/ev. php. URL_ID=4874&URL_DO=DO_TOPIC&URL_SECTION=201. html – African Situation http: //www. umich. edu/~gs 265/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/Biology. Pages/S/Sewage. Treatment. html Sewage treatment principles http: //www. coastal. ca. gov/desalrpt/dchap 1. html - Seawater Desalination http: //www. nature. com/nature/focus/water/index. html - Global Water Crisis Articles http: //news. nationalgeographic. com/news/2000/07/0714_water. html - Water and Peace in the Middle East http: //answers. google. com/answers/threadview? id=34014 – Further Resources for Desalination (specifically charitable) http: //www. mwra. state. ma. us/03 sewer/html/sewditp. htm - Detailed WW Treatment

Seawater Composition Element O H Cl Na Mg S Ca K Br C Au % by mass 85. 84 10. 82 1. 94 1. 08 0. 1292 0. 091 0. 04 0. 0067 0. 0028 less Component H 2 O Cl. Na+ Mg 2+ SO 4, 2 Ca 2+ K+ C inorganic Br. B total Sr 2+ F- molality (mol/kg) 53. 6 0. 546 0. 469 0. 0528 0. 0282 0. 0103 0. 0102 0. 00206 0. 000844 0. 000416 0. 000091 0. 000068