Household Water Treatment and Safe Storage Factsheet: Source ...
Household Water Treatment and Safe Storage Factsheet: Source ...
Household Water Treatment and Safe Storage Factsheet: Source ...
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<strong>Household</strong> <strong>Water</strong> <strong>Treatment</strong> <strong>and</strong> <strong>Safe</strong> <strong>Storage</strong><br />
<strong>Factsheet</strong>: Ultraviolet (UV) Disinfection Key Data<br />
Inlet <strong>Water</strong> Criteria<br />
<br />
<br />
Turbidity < 5 NTU (Nephelometric Turbidity Units)<br />
Iron < 1 ppm (parts per million)<br />
<strong>Treatment</strong> Efficiency<br />
Bacteria Viruses Protozoa Helminths Turbidity Chemicals<br />
Laboratory > 99.99% 0 > 99.99% 0 > 99.99% 0 > 99.9% 0 0% 0%<br />
Field<br />
97% to<br />
0,3<br />
100%<br />
Not available Not available Not available 0% 0%<br />
1 Cohn (2002)<br />
2<br />
Lang et al. (2006)<br />
Gadgil et al. (1998)<br />
Effectiveness depends on UV dose; these numbers are for NSF St<strong>and</strong>ard 40 mW-s/cm 2<br />
Required UV dose varies with water quality (e.g. turbidity, organic matter, pH)<br />
Operating Criteria<br />
Flow Rate Batch Volume Daily <strong>Water</strong> Supply<br />
5 litres/minute 1 Not applicable 2,000 litres 1<br />
1 Depends on the UV tube/apparatus design<br />
<br />
<br />
Flow <strong>and</strong> volume depend on system design<br />
Very turbid water should be sedimented or filtered prior to UV treatment<br />
Robustness<br />
<br />
<br />
<br />
<br />
Requires regular source of electricity, either through a grid or solar panels<br />
Requires supply chain, market availability <strong>and</strong> regular purchase of UV bulbs<br />
The design flow rate must be maintained by the user to ensure adequate UV dosing<br />
If electricity is intermittent, water can be treated when electricity is available <strong>and</strong> stored<br />
Estimated Lifespan<br />
<br />
<br />
10+ years<br />
UV bulbs should be replaced every 12 months (dirty or scratched bulbs reduce performance)<br />
Manufacturing Requirements<br />
Worldwide Producers:<br />
Some companies make UV tubes for household water treatment (e.g. UV <strong>Water</strong>works, USA)<br />
UV bulbs are available in various sizes from most major lamp manufacturers (e.g. General<br />
Electric, Sylvania, Phillips)<br />
Local Production:<br />
<strong>Household</strong> UV treatment units can be manufactured from local materials provided adequate<br />
knowledge <strong>and</strong> UV bulbs are available<br />
Design will vary depending on local materials available<br />
Materials:<br />
Feed container<br />
PVC tubing, or metal, pottery or cement channel<br />
Stainless steel sheet metal