WATER SUPPLY TECHNOLOGIESWATER SUPPLY TECHNOLOGIES
• Dug well (h
SOURCES OF DRINKING WATER(1) Ground Water
the main source of water supply in urban and rural
SOURCES OF DRINKING WATER
n the main source of water supply in urban and rural areas
n Free from Pathogens and requires no treatmentn Free from Pathogens and requires no treatment
q Urban Area: power driven production wellsaccess to safe drinking water-99%access to safe drinking water-99%Public water suply-47%
q Rural Area: Hand pumpsq Rural Area: Hand pumps90% have access to tubewell within 150 m
(2) Surface Water: Pond sand filter (suitable for coastal belt)(2) Surface Water: Pond sand filter (suitable for coastal belt)
(3) Rain Water: Rain water harvesting (Suitable for arsenic (3) Rain Water: Rain water harvesting (Suitable for arsenic affected areas)
•Oldest method, low cost, no special equipment or skill •Oldest method, low cost, no special equipment or skill necessary.
ØA hole is dug to a depthbelow the GWT(1.2mand Dia >1.2mØDepth of Communitydug-well=20~30 mdug-well=20~30 mØWalls are lined toprevent water seeping,prevent caving andcollapse of soil duringconstructionconstruction
Closed Dug well by tubewellOpen Dug well
Bacterial contamination of well waterof well water
n Can be Protected bysealing the well top withsealing the well top withwater tight concrete slab
Application areas:Application areas:In Hilly areas, where handpump tubewells are not alwayspossible. In acute Arsenic and Iron problem areas, becauseDug well water is free from Arsenic and IronDug well water is free from Arsenic and Iron
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n
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Ø Draw water from shallow depth by creatingØ Draw water from shallow depth by creatingvacuum in the suction pipe
Ø Extract water from a depth of 7.5m
1. No. 6 handpump tubewell
2. Rower pump tubewell
3. Disco pump tubewell
No. 6 Hand Pump TubewellNo. 6 Hand Pump Tubewell
• Barrel diameter is 6 inch
• Theoretical lifting capacity 32.8 ft• Theoretical lifting capacity 32.8 ft
• Average Discharge 30~40 liters /min
• Design Life: 15 ~20 years or more
Components:Components:
üHandpump
üBlind pipe (rising pipe)
üStrainer/screen: 38mm dia PVCüStrainer/screen: 38mm dia PVC
üSand trap
No. 6 Hand Pump TubewellNo. 6 Hand Pump Tubewell
• Barrel diameter is 6 inch
• Theoretical lifting capacity 32.8 ft• Theoretical lifting capacity 32.8 ft
• Average Discharge 30~40 liters /min
• Design Life: 15 ~20 years or more
Components:Components:
üHandpump
üBlind pipe (rising pipe)
üStrainer/screen: 38mm dia PVCüStrainer/screen: 38mm dia PVC
üSand trap
No. 6 Hand Pump TubewellNo. 6 Hand Pump Tubewell
• Barrel diameter is 6 inch
• Theoretical lifting capacity 32.8 ft• Theoretical lifting capacity 32.8 ft
• Average Discharge 30~40 liters /min
• Design Life: 15 ~20 years or more
Components:Components:
üHandpump
üBlind pipe (rising pipe)
üStrainer/screen: 38mm dia PVCüStrainer/screen: 38mm dia PVC
üSand trap
No. 6 Hand Pump TubewellNo. 6 Hand Pump Tubewell
• Barrel diameter is 6 inch
• Theoretical lifting capacity 32.8 ft• Theoretical lifting capacity 32.8 ft
• Average Discharge 30~40 liters /min
• Design Life: 15 ~20 years or more
Components:Components:
üHandpump
üBlind pipe (rising pipe)
üStrainer/screen: 38mm dia PVCüStrainer/screen: 38mm dia PVC
üSand trap
Working Principle:²A vacuum is created within the²A vacuum is created within thecylinder of the pump by raising thepiston.in order to fill up the vacuumpiston.in order to fill up the vacuum,water enters in the cylinder.
²² In the second stoke when thepiston is lowered down,the waterpiston is lowered down,the waterenters in the upper chamber andcomes outs of the pump through thecomes outs of the pump through thespout.
ØModified No.6 hand pump
ØSuction action is extendedØSuction action is extendedby extending the suction rodabout 1-3 m.about 1-3 m.
ØAbout 75 mm diameter GIØAbout 75 mm diameter GIpipe is used as casing.
Øh = 7-10mØh = 7-10m
Due to irrigation in dry season WT goes down, so,
Øh = 15 - 30m
Due to irrigation in dry season WT goes down, so,No. 6 handpumps go out of operation.
Øh = 15 - 30m
ØTara Handpump tubewell ØTara Handpump tubewell
Ø Moon Handpump tubewell Ø Moon Handpump tubewell
Ø Bangla Handpump tubewell
ØMark-II Handpump tubewell
Øh = 15 mØh = 15 m
Ø expected life 3 to 5 years
ØAverage discharge 24 litres /min
ØMain components: pumphead, handle, pump ØMain components: pumphead, handle, pump rod, piston assembly, foot valve assembly and cylinder.
ØThe lower part is similar to No. 6 handpump.
This pump does not proved to be user friendly. friendly.
Problems:
q Because of direct actions, more force is required even at low head
q Buoyancing forces is not always available due to leakage due to leakage
qModerate output for 7m lift and very low output for 12m lift.output for 12m lift.
q Repairing is inconvenient
ØMoon handpump tubewell is a modified Tara ØMoon handpump tubewell is a modified Tara H.P.
ØThe direct action of Tara H.P. is ØThe direct action of Tara H.P. is uncomfortable.
ØThe head of Tara HP is replaced by the head ØThe head of Tara HP is replaced by the head of No.6 hand pump to get the advantage of lever action.lever action.
ØPVC pump rod is replaced by steed rod
Ø Suitable for lifting water upto 25 mØ Suitable for lifting water upto 25 m
ØMaximum Discharge 36 litres /min
A modified type of Tara H.P. popular in IndiaIndia
Øthe pumping rod is extended to set the piston assembly at a desired depth of over piston assembly at a desired depth of over 30m.
ØThe dia of raising pipe is reduced to ØThe dia of raising pipe is reduced to reduce the load of water on piston
ØThe length of handle is extended to enhance the lever action
ØDue to long column of water wt. above the piston, more operation force is needed.
Manually Operated Deep Tubewell
ØA tubewell penetrating at least oneØA tubewell penetrating at least oneimpervious layer
ØH >75mØH >75m
ØIn coastal belt, it can be as deep as300m300m
Components:Components:
ØSame as No. 6 hand pump tubewellwith the addition of more blind pipeswith the addition of more blind pipes
ØInstallation cost is high
Dug well:v At least 10 m away from latrines, abandoned ditch or marshy land.v At least 10 m away from latrines, abandoned ditch or marshy land.v Should not be installed near pond, canal or riverv Should not be installed under any tree, near any bush, by the side of
road or any disposal site of industries.road or any disposal site of industries.v Users accessibility, Safety factor and comfort for lifting water.
Hand Pump Tube well:v At least 10 m away from latrines.v At least 10 m away from latrines.v Should be installed at a place with higher elevation, which is not
usually floodedv Should be accessible to users and caretakers .v Should be accessible to users and caretakers .
Tubewells in BangladeshBangladesh
Mark-II Tubewell in India and Pakistan
The design of tubewells mainly involves the The design of tubewells mainly involves the selection ofLengthLengthDiameterDiameterslot opening of the screendesign of shroud materialsdesign of shroud materials
evpDLQWhere
Q= Design Discharge of the TubewellQ= Design Discharge of the Tubewell
D= Diameter of the screen
L=Length of the screen
p= Percent opening of the screenp= Percent opening of the screen
Ve = Permissible entrance velocity (0.010 ~ 0.03 m/s)
Determination of Slot size of the strainer
D10 is that sieve size through which 10% of the sampleD10 is that sieve size through which 10% of the sampleshall pass and 90% are retained
If the slot size is required to be increased, the tubewell has toIf the slot size is required to be increased, the tubewell has tobe shrouded with coarse-grained materials.
1. Draw particle size distribution curves of all the visible 1. Draw particle size distribution curves of all the visible different strata
2. Select the particle size distribution curve of the finest 2. Select the particle size distribution curve of the finest sand for the design of the shrouding material.
3. Multiply the 70% retained size of the sand by a factor 4 if the sand is fine an uniform or 6 if the sand is coarser or the sand is fine an uniform or 6 if the sand is coarser or non-uniform
4. Draw a smooth curve representing a shrouding material 4. Draw a smooth curve representing a shrouding material with a uniformity coefficient of 2.5 or less through this 70% retention point of the material. 70% retention point of the material.
5. Prepare specifications for the shrouding material by selecting four or five standar sieve sizes
6. Finally, select the size of the slot of the screen that will 6. Finally, select the size of the slot of the screen that will retain 90% or more of tt shrouding material.
Sinking of handpump tubewell
n Sludger methodn Rotary drilling method.
Sludger / Dheki MethodSludger / Dheki Method
Installation of handpump tubewell
Why Maintenance is required
vv Excessive pumping cause clogging nearscreen
v Pumping of water with high mineralcontent may be cause encrustationcontent may be cause encrustation
- HCl in diluted solution form
v leakage due to corrosion- cement grouting
Maintenance of handpump tubewell
vv Rehabilitation of chocked-up tubewellv Desandingv Desandingv Re-sinkingv
Tubewell are choked up due to
v Improper selection of screenv Improper selection of screenv Incrustation of screenv entry of clay or sand
Technology Inst. Cost (TK.) Adv. Disadv.
Dugwell Low Low costSanitary
protection is difficultdifficult
No. 6 Handpump 2000 - 4000
Suitable for shallow WT
May produce high As contentHandpump 2000 - 4000 shallow WT high As content
Tara 13000-15000 Suitable for LWT More force is Tara Handpump 13000-15000Suitable for LWT
zoneMore force is
required
Deep Usable in High installation Deep tubewell 50000-70000
Usable in coastal/saline
areas
High installation cost
Base year 1998
