water supply murray biedler july 09, 2012. water needs drinking food prep hygiene / washing agric /...
TRANSCRIPT
WATER SUPPLY
Murray BiedlerJuly 09, 2012
WATER NEEDSDrinking
Food Prep
Hygiene / Washing
Agric / Stock
CHARACTERISTICSof
WATER SUPPLY
Quantity Quality Access and Sources Treatment
Not static… constantly changing
WATER QUANTITY
Europe 150-litres/p/day average Emergencies
• 20-litres/p/day minimum• 5-litres/p/day: opening of emergency• Health centre: 1-2 litres/consultation• Hospital: 40-60 litres/patient/day (100 for
surgery)• Therapeutic feeding centre: 30 litres / child / day• Cattle: 30 l/animal/day • Small animals: 5 l/animal/day
WATER QUALITY
Bacteriological quality linked to:• Faecal contamination indicative of
pathogens (e.g. cholera or typhoid) (rapid assessment in field)
Chemical quality linked to:• Geological surroundings, agricultural or
other industrial/commercial activities (rapid assessment difficult lab required)
WATER QUALITY
Good Quality: Contains no pathogens Low concentration of toxic products Clear (low turbidity)
Is not too salty or mineralized Colour, odour and taste acceptable
WATER ACCESS:CHALLENGES
Time
Cost
Distance & Security
WATER ACESS: SOURCES
Surface water• rivers, lakes, ponds
(access seasonal) Ground water
• Difficult access but can be better quality
Precipitation• Seasonal: rain, snow,
fog capture
WATER ACCESS: SURFACE
On site pumps to storage / tower
Gravity network, pipes & taps
WATER ACCESS: GROUNDWATER
Hand-dug wells: hand pumps, buckets
Boreholes (shallow &
deep) pumps: hand, motor, solar, wind…
WATER ACCESS: SPRINGS
Springs: on site pumps or gravity into networks, pipes & taps
WATER ACCESS: PRECIPITATION
Rainwater collection gravity to tanks networks, pipes & taps
WATER ACCESS: STORAGE Storage provides
availability on regular basis
Storage tanks provide:• Treatment of large
volumes• Pressure with gravity
Dams: surface and subsurface; seasonal & precipitation constraints
WATER ACCESS DISTRIBUTION 1 tap/200 persons for
displaced populations Health facilities: taps for
staff, patients & visitors
Container distribution
WATER TREATMENT
Chlorination simplest & most efficient way to kill micro-organisms
Residual chlorine necessary to attack further contaminations
Chlorination becomes inefficient if the water is too dirty or turbid
SEDIMENTATION & FILTRATION
Water stored until suspended particles settle Water can be filtered with sand or other
designed materials Coagulation-flocculation for heavy turbidity
using chemicals (e.g.ferric chloride or aluminium sulphate)
DOMESTIC STORAGE
Container
lid or top (e.g: jerry can) or a narrow opening(transport)kept clean regularly dosed for residual chlorine(storage)
MAIN ISSUES TO BE CONSIDERED
NEEDS ANALYSIS
POTENTIAL
SOURCES
TECHNICAL
OPTIONS
ENSURING
QUALITY
SANITATION AND
HYGIENE
AVAILABLE
QUANTITY
ADAPTED
WATER SUPPLY