Water

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Water

  1. 1. Water
  2. 2. Water <ul><li>one of the most fascinating compounds on earth </li></ul><ul><li>necessary ingredient for all living organisms </li></ul>
  3. 3. Water <ul><li>covers about 70% of the earth of the earth’s surface </li></ul><ul><li>340 million cubic miles of water on the planet </li></ul>
  4. 5. The Hydrologic Cycle <ul><li>Water Basics </li></ul><ul><ul><li>Sea water 97.2% </li></ul></ul><ul><ul><li>Fresh Water 2.8% </li></ul></ul><ul><ul><ul><li>Polar ice & glaciers 2.15% </li></ul></ul></ul><ul><ul><ul><li>Groundwater 0.62% </li></ul></ul></ul><ul><ul><ul><li>Lakes and Rivers 0.01% </li></ul></ul></ul>
  5. 8. Water Facts: The Numbers Game <ul><li>97% of freshwater resources in polar regions </li></ul><ul><li>1,844: U.S. per capita annual withdrawal of cubic meters of freshwater </li></ul><ul><li>664: World per capita annual withdrawal of cubic meters of freshwater </li></ul><ul><li>500,000 tons of pollutants entering U.S. lakes and rivers daily </li></ul><ul><li>1 liter of oil can contaminate up to 2 million liters of water </li></ul><ul><li>67 million pounds of pesticides applied in U.S. per year </li></ul><ul><li>50% of world’s population affected by water shortages </li></ul><ul><li>30% of U.S. area under drought conditions for 2002 </li></ul>Sources: Enviroment Canada, 2003; Public Broadcasting Station, 2002; U.S. Environmental Protection Agency, 2002.
  6. 11. The Hydrologic Cycle <ul><li>The Three Fates of Precipitation </li></ul><ul><ul><li>Infiltration </li></ul></ul><ul><ul><ul><li>The movement of water into rocks or soil through cracks and pore spaces </li></ul></ul></ul><ul><ul><li>Runoff </li></ul></ul><ul><ul><ul><li>Water that flows over the land </li></ul></ul></ul><ul><ul><li>Transpiration/Evapotranspiration </li></ul></ul><ul><ul><ul><li>the release of water vapor to the atmosphere by plants </li></ul></ul></ul>
  7. 14. The water cycle <ul><li>the amount of water on and around this planet is fairly constant </li></ul><ul><li>availability of water is not as constant </li></ul>
  8. 15. Water Quality and Impacts 90-95% of sewage and 70% of industrial wastes are dumped untreated into surface water.
  9. 16. Freshwater Biodiversity More than 20% of freshwater fish species have become extinct, threatened or endangered. In North America 67% of mussels, 37% freshwater fish, and 40% of amphibians are threatened or have become extinct. Source: Living Planet Report, WWF 2002 Freshwater Species Population Index
  10. 17. “ Water contributes much to health. Good health is the essence of development” Water, sanitation and health : the current situation The prevailing worldwide situation regarding water supply and sanitation services is a source of concern in different respects. <ul><li>Globally (WHO, 2000) </li></ul><ul><li>some 1.1 billion people are currently without access to improved water supply </li></ul>
  11. 18. “ Water and Sanitation are intimately linked to good health” <ul><li>Globally (WHO, 2000) </li></ul><ul><li>some 2.4 billion don't benefit from any form of improved sanitation services </li></ul>Water, sanitation and health : the current situation
  12. 19. Definitions of access to improved water supply and improved sanitation Source: WHO and UNICEF (2003) Access for water supply Availability of at least 20 liters per person per day from an &quot;improved&quot; source within one kilometer of the user's dwelling. Improved Household connection Public standpipe Borehole Protected dug well Protected spring Rainwater collection Not Improved unprotected well unprotected spring vendor provided water tanker truck water Improved connection to a public sewer connection to a septic system pour-flush latrine simple pit latrine ventilated improved pit latrine Access to sanitation Excreta disposal systems are considered adequate if they are private and if they separate human excreta from human contact. Not Improved service or bucket latrines (where excreta are manually removed) shared and public latrines latrines with an open pit
  13. 20. Diarrhea : About 4 billion cases per year cause 2.2 million deaths , mostly among children under five . Intestinal worms : Infect about 10% of the population of the developing world Trachoma : About 6 million people are blind from trachoma . providing improved water supply could reduce the infection rate by 25%. Schistosomiasis : About 200 million people are infected . Improved water supply and sanitation could reduce infection rate by 77%. Source: Global water supply and Sanitation Assessment. 2000 Report Most frequent diseases due to poor water supply and sanitation
  14. 21. Watershed
  15. 23. The Hydrologic Cycle <ul><li>Infiltration capacity of the soil is controlled by: </li></ul><ul><ul><li>Intensity and duration of rainfall </li></ul></ul><ul><ul><li>Soil saturation </li></ul></ul><ul><ul><li>Soil texture </li></ul></ul><ul><ul><li>Slope of the land </li></ul></ul><ul><ul><li>Nature of the vegetative cover </li></ul></ul>
  16. 24. The water cycle <ul><li>if the oceans were not recharged, their water level would decrease over 40 inches per year </li></ul>
  17. 25. Main Sources of Water <ul><li>Surface Water </li></ul><ul><ul><li>Lakes, rivers, reservoirs </li></ul></ul><ul><li>Ground Water </li></ul><ul><ul><li>In the Earth, flows through fractures and pores </li></ul></ul>
  18. 26. What is Groundwater? <ul><li>Water found in the pores and fractures of soil and bedrock </li></ul><ul><li>Largest reservoir of fresh water </li></ul><ul><li>Tends to be less polluted than surface water </li></ul>
  19. 27. What is Groundwater? <ul><li>An important erosional agent </li></ul><ul><ul><li>Groundwater is often mildly acidic </li></ul></ul><ul><ul><li>Contains weak carbonic acid </li></ul></ul><ul><ul><li>Forms caverns at or just below the zone of saturation </li></ul></ul><ul><ul><li>Karst topography on the surface </li></ul></ul>
  20. 28. Groundwater Movement & Storage <ul><li>Aquifer - A zone of Earth material capable of supplying groundwater at a useful rate from a well </li></ul>
  21. 29. Getting Groundwater Out of the Ground <ul><li>Extraction Methods </li></ul><ul><ul><li>“Natural” Methods </li></ul></ul><ul><ul><ul><li>Springs, Hot Springs, & Geysers </li></ul></ul></ul>
  22. 30. Getting Groundwater Out of the Ground <ul><li>Extraction Methods (continued) </li></ul><ul><ul><li>Man-made Methods </li></ul></ul><ul><ul><ul><li>Wells </li></ul></ul></ul>
  23. 31. Getting Groundwater Out of the Ground <ul><li>Problems with groundwater removal </li></ul><ul><ul><li>Non-renewable resource </li></ul></ul><ul><ul><li>Subsidence </li></ul></ul><ul><ul><li>Contamination </li></ul></ul>
  24. 33. Water and Food <ul><li>~85% of world consumptive water use to produce food </li></ul>
  25. 34. http://www.irrigation.org/ag_brochure1.htm Consumptive freshwater use in the United States:
  26. 35. U.S. Water Facts Source: U.S. Geological Survey, 2003
  27. 36. U.S. Water Facts Source: U.S. Geological Survey, 2003
  28. 37. Designing with Water
  29. 38. Source to Sink
  30. 43. Possibilities
  31. 46. Rainwater Harvesting <ul><li>= Collect rainwater from building roofs to use for other purposes instead of losing as runoff </li></ul><ul><li>Been around for thousands of years </li></ul><ul><li>Currently used all over the world, from </li></ul><ul><li>Haiti to the Berkeley hills </li></ul>
  32. 47. Low Cost Roofwater <ul><li>A house with a 1,000 sq. ft. roof could yield 600 gallons of rainwater from a one inch rainfall </li></ul><ul><li>A = (catchment area of building) </li></ul><ul><li>R = (inches of rain) </li></ul><ul><li>G = (total amount of collected rainwater) </li></ul><ul><li>(A) x (R) x (600 gallons) / 1000 = (G) </li></ul>
  33. 48. Simple as this… <ul><li>During the three monsoon months, drinking water needs of each house in this Karnataka village's 35-house colony are met by a simple saree based rainwater harvesting system. (Pic: Shree Padre) </li></ul>
  34. 49. Rainwater Harvesting System for House in Oregon
  35. 51. http://www.eng.warwick.ac.uk/DTU/rainwaterharvesting/
  36. 59. Domestic Uses <ul><li>In the US each person uses approximately 150 gallons of water per day </li></ul><ul><li>bath - 3-40 gallons </li></ul><ul><li>shower - 5 gallons per minute </li></ul>
  37. 60. Water Conservation <ul><li>= Technologies or ideas that can be used to reduce the amount of water consumed per person </li></ul><ul><li>Household level </li></ul><ul><ul><li>Residential use ~75% of urban demand </li></ul></ul><ul><ul><li>60% of residential use is indoors </li></ul></ul><ul><li>Source: Environmental Protection Agency, 2003. </li></ul>
  38. 61. Efficient Toilets <ul><li>40% of household water used in toilets </li></ul><ul><li>Conventional toilets use 3.5 – 5 gallons per flush </li></ul><ul><li>Alternatives </li></ul><ul><ul><li>Toilet displacement devices </li></ul></ul><ul><ul><li>Low flow: 1.6 gpf </li></ul></ul><ul><ul><li>Cascading toilets: use water from sink to flush </li></ul></ul><ul><ul><li>Composting toilets: little to no water used </li></ul></ul><ul><li>Energy Policy Act of 1992 - new home use toilets must operate on 1.6 gallons per flush or less </li></ul>Sources: Alexander, 2003; EPA, 2003; Oasis Design, 2003.
  39. 62. Composting Toilets Phoenix, Inc.
  40. 64. Showers <ul><li>30% of household water used in showers </li></ul><ul><li>Water consumption </li></ul><ul><ul><li>Standard: 4.5 gpm </li></ul></ul><ul><ul><li>Low-flow: 2.5 gpm </li></ul></ul><ul><ul><li>Ultra low-flow: 1.5 gpm </li></ul></ul><ul><li>Low-flow showerheads cost ~$5 and can save 20,000 gallons/year in a 4 person household </li></ul>Source: EPA, 2003.
  41. 65. Other household water uses <ul><li>Other appliances with low-flow alternatives </li></ul><ul><ul><li>Faucets = 5% of total indoor household use </li></ul></ul><ul><ul><li>Washing machines = 20% of total </li></ul></ul><ul><ul><li>Dish washers = up to 5% of total </li></ul></ul><ul><li>Save water and energy required to heat “extra” water </li></ul>Source: EPA, 2003.
  42. 67. What is Greywater? <ul><li>= Water that has been used in the home, except water from toilets (blackwater). </li></ul><ul><li>Dish, shower, sink and laundry water comprise 50-80% of residential wastewater </li></ul>
  43. 68. Source: USEPA 1992 Total Greywater= 59%
  44. 69. Source: Home Energy Magazine Online, July/August 1995.
  45. 72. Integrated Solutions
  46. 73. <ul><li>Filtration </li></ul><ul><li>Rapid sand filters </li></ul><ul><li>Do not remove fecal pathogens </li></ul><ul><li>Slow sand filters </li></ul><ul><li>More effective in removing particulates and microbial contaminants and are simpler to operate. </li></ul><ul><li>Low cost and Low maintenance </li></ul><ul><li>Carbon filters for household use </li></ul><ul><li>Fitted to municipal connection in the kitchen </li></ul><ul><li>Source: Ashok Gadgil, Drinking water in the developing countries, Ann.. Rev. Energy Environ. 1998 </li></ul>Water treatment
  47. 74. <ul><li>Chlorination </li></ul><ul><li>Used world wide </li></ul><ul><li>Cheap disinfectant </li></ul><ul><li>Residual free chlorine </li></ul><ul><li>In many smaller communities in developing countries various solid and liquid chemical forms of chlorine is used since they are safer to transport and handle than chlorine gas. </li></ul><ul><li>Disadvantages: </li></ul><ul><li>Large systems require skilled technical operators, repair and maintenance . </li></ul><ul><li>Disinfection by-products (DBPs) </li></ul><ul><li>Source: Ashok Gadgil, Drinking water in the developing countries, Ann.. Rev. Energy Environ. 1998 </li></ul>Water treatment
  48. 75. <ul><li>UV disinfection </li></ul><ul><li>Ultraviolet light in the wavelength 240 to 280 nm has been known to be of germicidal </li></ul><ul><li>Disinfection imparts no taste or odor </li></ul><ul><li>Presents no risks from overdosing or carcinogenic by-products </li></ul><ul><li>Scaling down plant size does not increase cost ($ 0.02 / m3 of water treated) </li></ul><ul><li>Disadvantages: </li></ul><ul><li>No residual disinfection and better to be used at point-of-use system </li></ul><ul><li>Biological films and chemical fouling. (when lamp is off during hours of disuse) </li></ul><ul><li>Makes it expensive and complex puts it beyond rural communities. </li></ul><ul><li>Can only be used with pressurized water source like tap water and not so useful for people collecting water from surface water or hand pumps. </li></ul><ul><li>Need of electricity </li></ul><ul><li>Source: Ashok Gadgil, Drinking water in the developing countries, Ann.. Rev. Energy Environ. 1998 </li></ul>Water treatment Conventional coaxial UV treatment unit
  49. 76. <ul><li>Pasteurization </li></ul><ul><li>Boiling the oldest form of obtaining water free of biological contaminants. </li></ul><ul><li>In many developing countries residents routinely boil their drinking water </li></ul><ul><li>- Half the population in China boil the water, mostly over biomass-fueled stoves. </li></ul><ul><li>Water does not need to be boiled to disinfect </li></ul><ul><li>Holding at high enough temperature ( 6 minutes at 70 C is sufficient) is sufficient to pasteurize the water to make it safe for drinking. </li></ul><ul><li>WHO recommends bringing the water to a vigorous boil for one minute at sea level and 1 degree more for every 100 m altitude gain. </li></ul><ul><li>Sustainable? </li></ul><ul><li>No…… most people do not have that much fuel for cooking the meals even. </li></ul><ul><li>- Average family will require 12 kg of wood for boiling the water to boil 35 liters of water. </li></ul><ul><li>It is economically unrealistic and environmentally unsustainable to recommend boiling daily drinking water to the poor in the developing world. </li></ul><ul><li>Source: Ashok Gadgil, Drinking water in the developing countries, Ann.. Rev. Energy Environ. 1998 </li></ul>Water treatment
  50. 77. <ul><li>Solar water disinfection (SODIS) </li></ul><ul><li>It is a simple water treatment method using solar UV-A radiation </li></ul><ul><li>and temperature to inactivate pathogens causing diarrhea. </li></ul><ul><li>SODIS is ideal to treat small quantities of water. </li></ul><ul><li>Contaminated water is filled into transparent plastic bottles </li></ul><ul><li>PET (Polyethylene Terephtalate) are preferred because they contain less UV-stabilisators than PVC </li></ul><ul><li>Exposed to full sunlight for six hours </li></ul><ul><li>Radiation in the spectrum of UV-A (wavelength 320-400nm) </li></ul><ul><li>Increased water temperature . </li></ul><ul><li>If the water temperatures raises above 50°C, the disinfection process is three times faster. </li></ul><ul><li>SODIS is more efficient in water containing high levels of oxygen. </li></ul>Water treatment Source and graphics: SANDEC (Water & Sanitation in Developing Countries) at EAWAG , Switzerland.
  51. 78. <ul><li>Solar water disinfection (SODIS) </li></ul>Water treatment Source and graphics: SANDEC (Water & Sanitation in Developing Countries) at EAWAG , Switzerland.
  52. 79. <ul><li>SODIS requires sun radiation and temperature: </li></ul><ul><li>Exposed to the sun for 6 hours if the sky is bright or up to 50% cloudy </li></ul><ul><li>Exposed to the sun for 2 consecutive days if the sky is 100% cloudy </li></ul><ul><li>If a water temperature of at least 50°C is reached, an exposure time of 1 hour is sufficient </li></ul><ul><li>The most favorable region for SODIS lies between latitudes 15°N/ S and 35°N/ S. </li></ul><ul><li>SODIS requires relatively clear water with a turbidity less than 30 NTU . Water Turbidity Test : Read the letters of the SODIS logo through the water. </li></ul>Source and graphics: SANDEC (Water & Sanitation in Developing Countries) at EAWAG , Switzerland. Water treatment
  53. 80. <ul><li>CCS (Ceramic Colloidal Silver) filter </li></ul><ul><li>An new alternative to conventional ceramic candle </li></ul><ul><li>filters is the CCS system. </li></ul><ul><li>It has a vessel-shaped filtering element which has a </li></ul><ul><li>bigger capacity and is easier to produce locally and is </li></ul><ul><li>less risky in use and maintenance . </li></ul><ul><li>Remove turbidity and 98- 100% of the harmful bacteria that cause diarrhea, cholera and other waterborne diseases. </li></ul><ul><li>Maintenance consist of cleaning with a brush and changing the US$ 3 filter element every 2 years. </li></ul><ul><li>If filled up twice a day the filter produces enough for a family of 6.   </li></ul>Source: http://www.practicafoundation.nl Water treatment
  54. 81. The Urban Watershed and Low Impact Design Materials courtesy of the SFPUC Urban Permaculture Institute
  55. 83. W h a t i s L o w I m p a c t D e s i g n ? <ul><li>LID is a stormwater management approach that aims to re-create and mimic these pre-development hydrologic processes by increasing retention, detention, infiltration, and treatment of stormwater runoff at its source. </li></ul><ul><li>LID is a distinct management strategy that emphasizes on-site source control and multi-functional design, rather than conventional pipes and gutters. </li></ul><ul><li>Whereas BMPs are the individual, discrete water quality controls, LID is a comprehensive, watershed- or catchment-based approach. </li></ul><ul><li>These decentralized, smallscale stormwater controls allow greater adaptability to changing environmental and economic conditions than centralized systems. </li></ul>
  56. 85. Eco Roofs <ul><li>Green roofs, or eco-roofs, are roofs that are entirely or partially covered with vegetation and soils. </li></ul><ul><li>Eco-roofs have been popular in Europe for decades and have grown in popularity in the U.S. Recently as they provide multiple environmental benefits. </li></ul><ul><li>Eco-roofs improve water quality by filtering contaminants as the runoff flows through the growing medium or through direct plant uptake. </li></ul><ul><li>Studies have shown reduced concentrations of suspended solids, copper, zinc, and PAHs (polycyclic aromatic hydrocarbons) from eco-roof runoff . </li></ul>
  57. 87. <ul><li>An intensive eco-roof may consist of shrubs and small trees planted in deep soil (more than 6 inches) arranged with walking paths and seating areas and often provide access for people. </li></ul><ul><li>In contrast, an extensive eco-roof includes shallow layers (less than 6 inches) of low-growing vegetation and is more appropriate for roofs with structural limitations. </li></ul><ul><li>Both categories of eco-roofs include engineered soils as a growing medium, subsurface drainage piping, and a waterproof membrane to protect the roof structure. </li></ul>D e s i g n D e t a i l s
  58. 88. Downspout Disconnect <ul><li>Downspout disconnection, also called roof drain diversion, involves diverting rooftop drainage directly into infiltration, detention, or storage facilities instead of into the sewer. </li></ul><ul><li>Rainwater can be harvested from most types of rooftops. </li></ul><ul><li>In areas where site conditions allow infiltration, roof drainage can be conveyed to drainless bioretention planters, dry wells, or can be simply dispersed onto a rain garden, lawn, or landscaped area </li></ul><ul><li>On sites that are not amenable to infi ltration, roof drains can be routed into cisterns which are available in a range of materials, sizes, and models. </li></ul>
  59. 90. Rain Gardens <ul><li>Rain gardens are stormwater facilities integrated into depressed landscape areas. </li></ul><ul><li>They are designed to capture and infiltrate stormwater runoff. </li></ul><ul><li>Rain gardens include water-tolerant plants in permeable soils with high organic contents that absorb stormwater and transpire it back into the atmosphere. </li></ul><ul><li>Rain gardens are a subset of bioretention planters except that they do not typically include engineered soils or an under-drain connection. </li></ul><ul><li>Plant species can be selected to stack functions and provide yields. </li></ul>
  60. 92. Typical Rain Garden
  61. 93. Bioretention Planters <ul><li>Bioretention is the use of plants, engineered soils, and a rock sub-base to slow, store, and remove pollutants from stormwater runoff. </li></ul><ul><li>Bioretention planters improve stormwater quality, reduce overall volumes, and delay and reduce stormwater runoff peak flows. </li></ul><ul><li>Bioretention planters can vary in size from small, vegetated swales to multi-acre parks; however, there are limits to the size of the drainage area that can be handled. </li></ul><ul><li>System designs can be adapted to a variety of physical conditions including parking lots, roadway median strips and right-of-ways, parks, residential yards, and other landscaped areas and can also be included in the retrofits of existing sites. </li></ul>
  62. 96. Street-side bioretention planter based on Portland’s Green Streets
  63. 97. Detention Basins <ul><li>Detention basins are temporary holding areas for stormwater that store peak flows and slowly release them, lessening the demand on treatment facilities during storm events and preventing flooding. </li></ul><ul><li>Generally, detention basins are designed to fi ll and empty within 24 to 48 hours of a storm event and therefore could reduce peak flows and combined sewer overflows. </li></ul><ul><li>If designed with vegetation, basins can also create habitat and clean the air whereas underground basins do not. </li></ul><ul><li>Surface detention basins require relatively flat slopes . </li></ul>

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