Latest Challenges & Technological Solutions of Drip Water Irrigation

1. Drip Water Irrigation
Latest Challenges & Technological Solutions
Sachin Garg
Dept. of Electrical Engineering
Indian Institute of Technology Delhi
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2nd August 2014

2. Introduction
 Drip components
apply water only
to root zone area
near plant
 Efficiency as high
as 90-95 %
Drip Emitter in Operation
(Photo source: Irrigation Direct)
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3. Latest Challenges
 Sediments in surface water
 Algae growth on filter screen
- cause frequent clogging problems
 Iron present in water
- turns into solid iron oxide & blocks the nozzle
openings of emitter
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4. The first challenge – Sediments & Algae
 High load of sediment can plug a normally-
sized screen filter in a short time
- self cleaning screen filter or a sand media filter is
used to prevent frequent plugging
 Algae may grow on filter screen
- small but continuous injection of Chlorine
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5. The second challenge – Iron Oxide
 Iron occurs naturally in water as –
- soluble bivalent Ferrous ion (Fe2+)
- non-soluble trivalent Ferric ion (Fe3+)
 Oxidizes to reddish-brown product when
exposed to air
 Iron levels above 0.1 ppm may cause clogging
of drip irrigation emitters
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6. Dealing with Iron
 Oxidation of iron –
Fe2+ Fe3+ Fe(OH)3
 Remove precipitated iron by Filtration
 Time depends on –
- pH
- temperature
- dissolved oxygen level
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7. Rate of Oxidation
 Time required for oxidation reduces with -
- high pH
- high temperature
- high dissolved oxygen
 At pH 7.0, 90% Fe+2 oxidation requires 1 hour at
21°C and 10 hours at 5°C.
 At pH 6.0 it requires 100 hours.
 Critical dissolved oxygen concentration is 2
ppm.
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8. Oxidation Methods
 Basin aeration pump
 Oxidants such as –
chlorine, chlorine dioxide, ozone & potassium
permanganate
 Shock treatment
 Add base to raise pH for the complete
oxidation of iron
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9. Filtration with Backwashing9

10. Advantages & Limitations
 Filter can be backwashed for re-use
 Can consistently remove high concentration of
iron to extreme low levels
 There are minimum flow rates required for
backwash
 Water pH should be 7 or higher, else pH
adjustment is necessary
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11. Low-cost Implementation
 Use oxygen in
air as oxidizing
agent in a Tray
Aerator
 Water simply
passed down
a series of
porous trays
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(Photo source: Eautarcie)

12. “Per Drop, More Crop”
Presentation available at: goo.gl/70TVfd
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