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
Amount of Water Treated
Low pressure mercy arc UV lamp can treat 1 or more
liters per minute.
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.
This device may be built with off-the-shelf
parts available throughout most countries.
Large quantities of disinfected water can be
Minimal behavior change required.
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
UV should not be used where the temperature
is less than 21 degrees C.
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
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.