UV WATER DISINFECTION SYSTEM
Preliminary concept by Bruce Stouter, Water Bucket Design
Comments welcome. For more information or schematic plans email:
[email protected]
RELIABLE AND MODERATE COST ULTRA-VIOLET WATER DISINFECTION
FOR LOW -PRESSURE OR HAND -POURED WATER SYSTEMS.
ABOVE : FILLING THE LOADING BUCKET
LEFT: SIMPLE EQUIPMENT INSIDE A PROTECTIVE BUCKET
HIGH EFFICACY:
Ultra-violet light kills viruses that can pass through slow sand filters and ceramic filter cartridges, and is
more effective than chlorine or PuR against parasitic cysts.
SIMPLE SYSTEM:
Requires little training, since water does not pass through unless bulb receives current. A loading bucket
has a hole drilled in the bottom, is placed 20- 32 inches higher than the top of the treatment bucket, and attached by tube. The
length of hose between the two buckets (32 inches maximum) limits speed of water flow to rates offering full disinfection.
EASY OPERATION:
No chemical measurement required. Less work than Sodis system. Disinfected water available almost
immediately.
SET UP :
OPERATE :
Hang or place bucket above unit
Plug in to current (or spread out solar panel)
Turn bulb on
Place container under outflow tube
Fill loading pail with water
Push start button
ADAPTABLE :
Can function as on-demand disinfection below water storage or as a stand-alone disinfection service. Can
be used on counter or hung on post or tree. Uses 120- 240 volts AC, power from 12 volt DC batteries, solar panels, or will run for 3
hours on self-contained backup battery. Install at point of use for large families or small institutions. For refugee camps can be at
shared health station. For small villages can be installed at community water supply or for-profit water store.
FULLY PORTABLE :
The unit fits in and is protected by a single 5 gallon/ 20 liter plastic bucket. Can be installed at a rural
surface water access point. Unit with 2 buckets weighs 12- 13 pounds. Systems do not require pump. Solar panels fold up and are
removable for security.
LOW MAINTENANCE :
Only moving part is a rugged solenoid valve designed for
millions of cycles. A small circuit monitors the current used by the bulb and the solenoid
does not allow water flow until the bulb warms up. Uses standard consumer under-sink
UV disinfectant unit with safety-shielded light. An
inexpensive 5 micron felt filter bag removes particles
which could shield viruses or bacteria from UV exposure.
The filter bags can be washed and replaced frequently if
used with turbid water sources ($2 each). Bulb must be
replaced after 2 years of constant use ($30). 12 v 4 amp
batteries common for cars or motorcycles may need
replacing (on small solar unit) every year ($20).
Unit costs detailed below are materials costs for separate
single purchase of all components, including a Sterilight
Copper Series SC1 by Viqua company of Guelph, Ontario,
Canada, $129 from Amazon (manufacturer’s list price is
$174). These costs might be reduced significantly by economies of scale.
Additional components for the basic unit total $81- $91 including:
Low pressure solenoid
$21
Power invertor
$20
Battery
$20
2 filter bags, single bucket, circuit, switch, tubing, wall plug and cigarette lighter plug, (and for solar models solar panel).
The equipment can be assembled by non-profit groups. Assembly involves soldering a small circuit. This circuit could possibly be
incorporated by the manufacturer into a safer model intended for use with solar energy or the type of intermittent power supply
regimes common in many parts of the world.
The equipment could be installed into buckets in-country as a for-profit business. With training, local installers might be able to test
water output, clean bulbs used with turbid water, and replace bulbs.
COST AND OUTPUT WITH NON-PROFIT ASSEMBLY
STANDARD MODEL
Cost
Gallons/Liters
per hour
Gallons/ Liters
per day
Number of families
served (if water is only
1
slightly turbid )
Cost per family per
month
(for 422 gallons/ 1600
2
L potable water )
Plug in AC/DC
Wall, car or
motorcycle battery
or generator
$220
75 g/ 280 L
1800 g/ 6800 L
100 FAMILIES (with
10 cents plus cost of
electricity
Small solar DC
10 watt panel
$260
3 hrs use
225 g/ 850 L
15 FAMILIES
79 cents total
Large solar DC
20 watt panel
$290
3- 7 hrs use
minimum
225- 500 g/ 8501985 L
15- 36 FAMILIES
37- 79 cents total
1
2
electricity supply 80% of
day)
(depending on hours of
sunlight)
To disinfect more turbid water (with a UV transmission of less than 75%), lower loading bucket for slower flow rate.
Cost per family/ month assuming bulb changed every 2 years, battery every year, 2 new filters per year. Assumes family of 6 needs
2.4 gallons (9 L) per person potable daily or 14 gallons (54L) total daily, about 1600 L per month. To include water for washing &
hygiene, families require 23 gallons (90 L) per day.
Increased flow rates can be achieved with a larger UV light (like Sterilight Copper Series
model SC2.5) in a 6 gallon bucket. This costs little more but if used at higher flow rates
can cut the cost per family in half. For increased flow the loading bucket can be hung on
a tree or post, but steps may be needed between the loading bucket and output hose.
Increased head pressure without pumping requires the bottom of the loading bucket to
be 48- 64 inches above the top of the lower bucket. This model is more appropriate for
a shared community location that can receive training and help setting up the unit.
RIGHT : 32 INCH HEIGHT FOR SC1 IS COMFORTABLE FOR STANDING ADULT.
BELOW : LOWER BUCKET PROTECTS EQUIPMENT FROM SUN , RAIN, OR DAMAGE .
COST AND OUTPUT WITH NON-PROFIT ASSEMBLY
HIGH FLOW MODEL
Cost
Gallons/Liters
per hour
Gallons/ Liters
per day
Number of families
served (if water is only
1
slightly turbid )
Cost per family per
month
(for 422 gallons/ 1600
2
L potable water )
Plug in AC/DC
Wall, car or
motorcycle battery
or generator
$240
150 g/ 565 L
3600 g/ 13,600 L
200 FAMILIES (with
5 cents plus cost of
electricity
Small solar DC
10 watt panel
$280
3 hrs use
450 g/ 1700 L
30 FAMILIES
42 cents total
Large solar DC
20 watt panel
$310
3- 7 hrs use
minimum
450- 1000 g/
1700- 3970 L
30- 72 FAMILIES
20- 42 cents total
1
2
electricity supply 80% of
day)
(depending on hours of
sunlight)
To disinfect more turbid water (with a UV transmission of less than 75%) lower loading bucket for slower flow rate.
Cost per family/ month assuming bulb changed every 2 years, battery every year, 2 new filters per year. Assumes family of 6 needs
2.4 gallons (9 L) per person potable daily or 14 gallons (54L) total daily, about 1600 L per month. To include water for washing &
hygiene, families require 23 gallons (90 L) per day.
This work is licensed under a Creative Commons Attribution 3.0 Unported License.