WATA Standard Operating Instructions Manual

WATA-Standard

OPERATING INSTRUCTIONS

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INDEX

1. Presentation .......................................................................................................3

2. Necessary materials ..........................................................................................4

3. Recommendations for the production of sodium hypochlorite ........................ 4

4. Water quality ....................................................................................................... 6

5. Sources of electricity/energy .............................................................................8

6. Procedure for producing sodium hypochlorite solution .................................10

7. Storage ..............................................................................................................11

8. Measuring active chlorine concentration (WataTest) ...................................... 12

9. Using sodium hypochlorite solution to chlorinate drinking water ................. 13

10. Testing drinking water with WataBlue

(determination of residual chlorine) .................................................................... 15

11. Using the sodium hypochlorite solution for disinfection/cleaning ............... 16

12. Stabilising the chlorine solution ....................................................................18

This guide explains how to use the WATA-Standard electrolyser to produce
a sodium hypochlorite solution with a 0.6% concentration of active chlorine
(6 g/L) that can be used for water treatment or disinfection purposes.
The WATA-Standard produces a sodium hypochlorite solution by electrolyzing
salt water. All that is needed are clear water, salt and electricity to use the
WATA-Standard. Water is chlorinated by adding a dose of sodium hypochlorite to
potentially contaminated water, thereby destroying at least 99%* of pathogenic
microorganisms in approximately 30 minutes.

1. PRESENTATION

The WATA-Standard produces 1 litre of sodium hypochlorite
solution per hour. Therefore, in 10 hours, it produces 10 litres
of solution, which can disinfect approximately 40,000 litres of
water per day, meeting the drinking water needs of 10,000 people
(4 L/pers/day). The WATA-Standard works with direct current and
consumes a nominal power of 48 W.

AC/DC power supply provided to hook up to the grid:

` Input voltage: 100 – 240 V AC
` Input frequency: 47 – 63 Hz
` Input current: 0.4 A / 230 VA C
` Output voltage: 12 V DC
` Nominal output current: 5 A

For use with solar power or a battery, a pair of crocodile
clips is provided, allowing for direct connection to a solar
electric panel or a battery. These should deliver a voltage
of 12 V DC.

W The device should only be used by a responsible person familiar with this

user guide.

W The sodium hypochlorite solution is harmless. In case of accidental

contact, rinse with clear water. Do not inhale or ingest.

W Store the sodium hypochlorite solution in an opaque, clean, labelled and

well-sealed flask, out of the reach of children.

W Never use metal containers for the procedure or for storage.

W Do not use or store near fire, flame or sparks.

*WHO, 2004, Water treatment and pathogen control, IWA publishing, p44-50

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2. NECESSARY MATERIALS

` WATA-Standard kit
` Ordinary salt
` Clear water
` Funnel

3. RECOMMENDATIONS
FOR THE PRODUCTION OF
SODIUM HYPOCHLORITE

W Choose one or several persons to be responsible for production

These persons should be trained and possess a general knowledge of
chemistry. Production with the WATA-Standard involves more than adding
salt to water. Failure to follow indicated procedures will lead to excessive
energy consumption that will adversely affect the proper functioning and life
span of the power supply.

W Choose an appropriate area and time for production

Production should be carried out in a ventilated area protected from dust
and the Sun’s rays, which has a temperature ideally between 25 and 30°C.

In countries with a hot climate, it is best to work early in the morning or in
the evening.

W Target output and concentration

The WATA-Standard works by electrolyzing salt water at 25 g/L to produce a
sodium hypochlorite solution with 6 g/L active chlorine. These parameters
should be followed in order to protect the life span of the device.

W In cases of unstable current, use a voltage regulator

If the power grid is subject to intermittent outages or sudden voltage
dips and surges (fluctuations in the intensity of light emitted by the bulbs
provides sufficient evidence that this is occurring), the power supply could
be destroyed. If this is the case, use a voltage regulator.

W Use with a generator

The generator should not run out of fuel while the WATA-Standard is in use.
Wait until the generator is stable before plugging in the WATA-Standard.

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When the procedure is complete, first unplug the WATA-Standard’s power
supply and then turn off the generator.

W Respect the 10-hour maximum period of use

To avoid the risk of overheating the power supply, do not use the
WATA-Standard for more than 10 consecutive hours. Successive productions
of 2 L are recommended.

W Overheating of the power supply

If overheating occurs, power will automatically shut off and then restart when
its internal temperature falls below 70°C. However, it is advisable to stop the
procedure and allow the power supply to cool down for 15 minutes.

W Respect the 6 g/L concentration

The WATA-Standard is designed to produce a sodium hypochlorite solution
with a 0.1 to 0.6% concentration of active chlorine. The concentration must
not exceed 0.7%. Prolonged use or excessive salt will result in raising the
temperature of the bath, not in increasing the concentration. If this occurs,
there is a risk of damaging the power supply and/or not achieving the 0.6%
concentration. Use WataTest to measure concentration once the procedure
is complete.

W Water temperature should be less than 42°C

In order to avoid the formation of undesirable by-products, the temperature
of the water should be checked regularly during production, using a clean
thermometer. The temperature should be less than 42°C. To begin the
procedure, use water with a temperature between 20 and 27°C.

W Use a log book

To facilitate the monitoring of chlorine production and to trace the origin
of problems that might arise, use a log book to record, each time the
WATA-Standard is used, the name of the person responsible for production,
the starting and finishing times of production and a short description of the
procedure. You’ll find examples in the “tool kit” on our website, www.antenna.ch.

W Regularly check production

Production should be checked at least every two hours or more frequently.
Watch for bubbles in the solution; this is proof that electrolysis is working
properly. Make sure that the power supply does not overheat. If there is a
possibility that dust or elements could fall into the solution, cover it with a
mosquito net type lid. This will allow the gas to escape and, if the area is well
ventilated, to dissipate.

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W Always clean the WATA-Standard after use

After each use, rinse the WATA-Standard with clean water. If after several
uses you notice white marks on the WATA-Standard, prepare a solution of 50%
vinegar (or lemon juice) and 50% clean water. Leave the device to soak for
several hours and then rinse it with clear water. Never scrub the titanium plates.

W Precautions

Do not bend the rods of the WATA-Standard or the electrical cables.

W Maintenance and repairs

Do not attempt to make electrical repairs if you are not competent in this
area. Contact Antenna or a specialist who will assist you or refer you to
appropriate services.

4. WATER QUALITY

The initial quality of the water used affects the efficiency of the sodium hypochlorite
production and efficacy of the water disinfection. The main parameters
characterizing the initial quality required for the water are pH and turbidity.

PH

PH is a measure of a solution’s acidity or alkalinity on a scale from 0 to 14, with a
pH of 7 indicating a neutral solution (such as pure water), <7 indicating an acid
solution (such as lemon juice) and >7 indicating an alkaline solution (such as
soap). PH affects chlorine’s ability to destroy microbes and viruses. Based on
World Health Organization recommendations, to effectively disinfect water with
sodium hypochlorite, the water used should have a pH between 6.5 and 8.5. It is
therefore recommended to measure pH.

TURBIDITY

Turbidity measures the opacity of a liquid. Water’s turbidity is caused by the
presence of solid particles in suspension (clay, sand, bacteria, chemical or metallic
residues, etc.) that make the water cloudy. Water with an elevated turbidity could
lead to the formation of undesirable products during the production of sodium
hypochlorite. During the chlorination process, elevated turbidity could diminish
the treatment’s efficacy. Following recommendations in the Sphere Handbook, to
guarantee optimal efficiency in producing sodium hypochlorite and chlorinating
drinking water, the water used should measure less than 5 units of turbidity.

For more than 5 units of turbidity, when the water is mildly turbid (<30 units of
turbidity), a double dose of sodium hypochlorite can be used, and when the water