UV Purifier Description

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Source: Winfried Farmer Aid Fund

Description

The homebrew gravity UV purifiers has been tested in schools, hospitals, and clinics in association with Medecins San Frontieres (MSF) in Myanmar (formerly Burma) and Women’s Union in Laos since 1998. The UV Purifier, a very simple technology, eliminates harmful microorganisms directly from the water source, using ultraviolet (UV) light as a disinfectant.

Development
Winfried Farmer Aid Fund

Performance

Amount of Water Treated
Low pressure mercy arc UV lamp can treat 1 or more liters per minute.

Contaminant Removal
UV lamps have been shown to kill 99.9 percent of vegetative bacteria, enteric viruses, and bacterial spores. Removal rates for UV lamps are lowered by the presence of organic matter, iron, sulfites, nitrites, and turbidity because these particles absorb UV radiation and shield microbes from being hit with UV rays. UV radiation does not treat chemical contamination or turbidity.

Ease of Use
UV lamp need to be cleaned regularly and handled with care because of their mercury content.

Benefits & Drawbacks

Benefits
  • This device may be built with off-the-shelf parts available throughout most countries.
  • Large quantities of disinfected water can be obtained quickly
  • Minimal behavior change required.
Drawbacks
  • Gravity flow
  • Replacing of UV lamp every 12 months
  • Requires electricity, either 120 or 240 volts AC, or 6 or 12 volts DC.
  • Need to filter the water and to remove any iron
  • UV should not be used where the temperature is less than 21 degrees C.
Ideal Situation
Communities with solar or grid electricity and financial ability to cover most of initial costs. The technology is excellent candidate for technology transfer models that emphasize small-scale, community workshop production that maximizes capacity for local maintenance and repair.

Costs

Costs
UV lamp costs include the actual unit, electricity, and replacement bulbs, which are typically needed once a year. A small batch UV lamp system used at the community level and all related expenses typically cost less than US$1 per household per year. When used at the household-level, UV lamps and related expenses average US$10 to $100 a year.

Resources

Contact Information

Robert Rau
Winfried Farmer Aid Fund
Honolulu, HI 96816-3802, USA
Email: rrau [at] hawaii [dot] rr [dot] com