Whom are WATA devices addressed to?
WATA devices are mainly addressed to:
Antenna Technologies also diffuses the devices within small rural communities. These projects are always supported by training and education programs.
Why is it useful to produce chlorine on the site of use?
Producing chlorine on the site of use avoids most storage and transportation problems. Whatever its chemical form, chlorine is rather difficult to store (it is very corrosive and instable) and its transportation is submitted to numerous restrictions (it can cause fires or explosions).
In which other forms is active chlorine available?
Sodium hypochlorite (NaClO) is available as a liquid. Being unstable, large distributors add it with a stabilizer (this mix is bleach). Calcium hypochlorite (Ca(ClO)2) is available as tablets or granules, but is highly corrosive and reactive. Dichlorine (Cl2) is commercialised pressurized (liquid) in metallic cylinders. Its transportation is dangerous and its use requires specific infrastructures.
When diffusing WATA devices within small rural communities, which accompanying measures are provided?
When Antenna Technologies diffuses WATA devices within communities which are not accustomed to water chlorination, training programs on water chlorination and water quality control are provided. A special effort is also made to sensitize on the protection of water sources. If needed, measures can be proposed and implemented for the protection of water resources.
How much does it cost to produce potable water with WATA?
The price of electricity
and the quality of water have considerable
variations from one country to another, as well as within a single
nation. It would therefore be very hazardous to advance a given cost of
drinking water production with WATA. The figures advanced below
thus only show an order of magnitude. Some data can nevertheless give
some elements of answer:
For example, only taking
into account the price of electricity
in
France (0.1085 €/kWh), the indicative price without initial investment
of one litre of active chlorine concentrate is below 0.01 Euro.
Thereby, the energy required for producing drinking water for a
community of 1000 people during one month costs about 1 Euro.
To
this, one has to add the liquidation of the devices (about 2 euros) and
the cost of 3kg of salt needed for the production of active chlorine.
What is saturated brine and why is it needed?
Saturated brine is a
solution in which the largest amount of salt has
been possibly dissolved. Water has a salt dissolution capacity of 360
g/l which is pretty constant regardless of the temperature. This means
that when one tries to dissolve very large quantities of salt in a
given volume of water, only the amount corresponding to the dissolution
capacity is actually dissolved. When this limit is reached, the
solution is known as saturated. From there on, grains of salt remain at
the bottom of the recipient.
WATA devices
can guarantee their production rate of
active
chlorine only if the initial salt concentration in water is precisely
25 g/l. The smaller the volume to electrolyse, the larger is the risk
of salt over-dosage. Yet, if no precision scale is available, it is
difficult to measure the 37.5 grams of salt which are necessary when
using a Mini-WATA
in a 1.5 litre bottle. It is therefore much easier
and safer to add 120 ml of saturated brine with a syringe. One thus
kills two birds with one stone because salt over-dosing in the water to
be electrolysed with a Mini-WATA could damage both its electrodes and
its electric alimentation (the solution's conductivity increases with
the salt concentration).
What is the difference between WATA and WATALYS?
WATA is the original
device described in the international patent WO
2005/044739 A1 registered by Antenna Technologies. WATALYS is a
non-permitted copy sold by Bulane, a commercial company based in
Geneva. Antenna
Technologies has decided not to bring this case before the court
because it has neither time nor means to do it.
How do WATA devices work?
Please refer to the page WATA - A compact device
Which electric sources can be used for the correct
functioning
of WATA devices?
Mini-WATA :
WATA :
Maxi-WATA :
How important is the quality of the water used for the electrolysis?
The water used for the electrolysis must be clear enough. Indeed, using water that is muddy or heavily concentrated in fluoride may reduce the electrodes' lifetime. Therefore, if the water is cloudy, it is necessary to filter it or to let the dirt deposit before using it for the electrolysis.
How many litres of drinking water can be treated with WATA?
Please refer to the page WATA - Line of products
Why is a battery needed when using a WATA with solar panels?
The intensity (amperes) of the electric current provided for the electrolysis with WATA has to be as constant as possible, in order to guarantee a concentration of 6 g/l of active chlorine in the solution produced. Photovoltaic cells can hardly deliver such a constant current intensity, it is therefore necessary to make use of a battery simultaneously to using a solar alimentation (as shown in the user guide). This way, the current intensity's variations are buffered and passing clouds, for example, thus don't reduce the device's production rate. If you intend using a WATA or Mini-WATA with solar alimentation, please contact Antenna Technologies.
How long can WATA devices be used for?
All three models of WATA devices are guaranteed for at least 20'000 hours of functioning under normal conditions. In practice, if they are properly used and well maintained, their lifetime is even longer.
How long can the chlorine concentrate be stored for?
Active
chlorine is very sensitive to light. The sun's ultraviolet (UV)
rays destroy it rapidly. To a lesser extent, air can also reduce the
concentrate's quality. It is therefore very important to store the
solution produced with WATA in closed and opaque recipients,
and to keep them in the shade. Under these conditions, the active
chlorine concentrate can be conserved during 4 weeks without any
problem, and then be used for drinking water chlorination or for
disinfection. Be aware that a recipient full of concentrate can be
conserved longer than one that is half empty (the air in the recipient
slowly oxidises the solution.
What is the WataTest reagent?
The WataTest reagent is a non-toxic product recently developed by
Antenna
Technologies which enables the fast and inexpensive measurement of the
concentration of sodium hypochlorite in the solution produced with
WATA. It is particularly useful to people whose business is to
produce and sell active chlorine for drinking water chlorination or
disinfection purposes. For them, it is essential to be able to
guarantee the right concentration of sodium hypochlorite of 6 g/l in
the solution they sell.
The WataTest reagent is still on its field-testing phase. It is
therefore
given for free to any owner of an WATA who asks for it.
What is drinking water chlorination?
Water chlorination consists in the addition of a given dose of active chlorine into potentially contaminated water, in order to kill all germs and pathogens. The dose added depends on the initial water quality. The disinfectant properties of chlorine are due to its strong oxidant power. About 30 minutes after mixing, all the germs are killed and the water is potable. It is important to treat clear water only. If it is muddy, cloudy or coloured, it must imperatively be filtered before chlorination. It is also possible to wait until all water particles deposit at the bottom of the recipient (sedimentation).
Against which diseases is chlorination efficient / inefficient?
Chlorine efficiently destroys the quasi-totality of pathogenic germs. It is therefore efficient for fighting against diarrhoeas, dysenteries, cholera, typhoid fever, salmonellosis and hepatitis A. On the other hand, it is inefficient against the cryptosporidium parasite and certain worm cysts (helminthes).
Is chlorination efficient against heavy metals and other chemical pollutants of water?
No, chlorine is a disinfectant, which means that it destroys and inactivates living germs which are source of diseases (bacteria, viruses and parasites). Chlorine cannot purify chemically contaminated water (pesticides, heavy metals, drugs...).
Why should one always leave residual chlorine in drinking water?
The World Health Organization (WHO) recommends leaving about 1 mg/l of chlorine (called residual chlorine) in drinking water. The residual chlorine is measured 30 minutes after the chlorination process. This enables 1- to be sure that all germs are eliminated and 2- to have a security margin against a new contamination after treatment. This security margin is only valid as long as the treated water is stored in a clean and closed recipient.
How can residual chlorine be tested?
Various colorimetric
tests for measuring residual chlorine in drinking
water are sold on the market. On one hand, there are paper strips that
must be dipped in the water to be tested. On the other hand, there are
DPD (diethyl-para-phenylene diamine) tablets which react when dissolved
into a small volume of water. Comparing the colour of the reaction with
a sample of control colours tells the residual chlorine concentration.
However, the paper strips have shown not to be reliable enough, whereas
DPD tablets are very costly and toxic.
Antenna Technologies therefore recently developed a new reagent, called WataBlue
reagent, which enables a very reliable measurement of residual chlorine
in drinking water at extremely low cost.
What are the WataTest & WataBlue reagents?
Please refer to the page WATA - Quality control
What are the other methods to make potable water?
Besides chlorination, the main water disinfection methods are:
What are the advantages of chlorination over other methods?
The main advantages
of chlorination are its low cost and the
comparatively little infrastructures it requires. Moreover, the
residual chlorine provides a security margin against a new
contamination by pathogenic micro-organisms, which is not the case with
other drinking water disinfection methods. Also, chlorination only
enables an absolutely reliable quality control.
What are the advantages of WATA over solar water disinfection methods such as the SODIS process?
Disinfection of drinking water with solar UV radiations is a widely used method in developing countries. Relatively inexpensive, it is however efficient on a very small scale only. Indeed, plastic bottles of maximum 2 litres shall be exposed to sunlight during 6 to 48 hours - depending on the weather - in order to disinfect drinking water from pathogenic micro-organisms. On the same time basis, WATA enables disinfecting thousands of litres of drinking water. Therefore, for equivalent volumes, WATA induces a much lesser workload and also a lower production cost. Moreover, chlorination enables an immediate, inexpensive and totally reliable quality control.
Whom is the disinfection with active chlorine addressed to?
In the first place,
it is useful to hospitals and other health clinics.
Disinfection with active chlorine can indeed drastically reduce the
occurrence of insufficient hygiene-related diseases. On the other hand,
it can also be useful in small food-related businesses such as
butcheries,
groceries, canning factories or restaurants. Access to quality chlorine
at
reasonable cost is also interesting for households, who can use it for
regular cleaning of sensitive rooms and surfaces (kitchen,
latrines...).
What are the advantages of disinfection with the concentrated solution of active chlorine?
Disinfection with the
active chlorine concentrate is very efficient and
inexpensive. Its range of efficiency is very wide; the solution can be
used for various purposes depending of its degree of dilution:
Active chlorine has a very strong oxidising power which kills or inactivates the great majority of living germs. In medical institutions, the disinfection of equipments with the active chlorine concentrate is also efficient against HIV/AIDS. However, be aware that it is not equivalent to a sterilisation! Last advantage: the solution produced with WATA is less toxic than bleach.
Can the chlorine concentrate be used for the sterilisation of surgical instruments?
Chlorine disinfection is not a sterilisation. The chlorine concentrate cannot be used for sterilising surgical instruments. These have to be sterilised in an autoclave or a hot air oven.
What is the difference between bleach and the solution produced with WATA?
There are two fundamental differences between bleach and the concentrated solution of active chlorine produced with WATA. 1- Bleach contains a stabilizer (caustic soda) to raise its pH and thus ensure a longer lifetime to the product. 2- The solution produced with WATA is five times less concentrated in chlorine than bleach. However, as it contains no caustic soda, the active chlorine reacts faster.
Also, for the very same reason, the solution produced with WATA
it not corrosive. It can therefore be used for
disinfecting wounds (it corresponds to Dakin solution, well-known
amongst doctors and nurses). Moreover, drinking bleach is very
dangerous because of the toxicity caustic soda. On the other hand, an
intake of the solution produced with WATA is certainly
displeasing, but not risky.
How long can the active chlorine concentrate produced with WATA be stored?
If stored in adequate conditions (clean, opaque and closed recipients), the chlorine concentrate remains stable during minimum one month. However, it can easily be used during six months, even though its disinfectant power tends to weaken slowly.
What is Dakin solution and should it be used?
Dakin solution is a liquid concentrated with active chlorine, which has antiseptic properties. Invented during World War I, it was used to disinfect open or infected wounds. The active chlorine concentrate produced with WATA devices corresponds to Dakin solution. It can therefore be used without dilution, applied with a clean compress on the wound to disinfect
Is it dangerous to use the WATA technology?
Mini-WATA :
WATA :
Maxi-WATA :
What are the risks related to the intake, especially by children, of the concentrated solution of active chlorine?
The intake of concentrated active chlorine is very unlikely to happen,
considering its irritant smell and bad taste. Nevertheless, in case a
child takes a large gulp of it, it is not necessary to run to the
nearest hospital. Just make the child drink potable water in order to
lessen the bad taste. To the contrary, an intake of bleach is truly
dangerous, because of the toxic caustic soda it contains.
Is residual chlorine harmful in any way?
So far, no study could prove any harmful impact of residual chlorine on human health, when found at concentrations such as those recommended by WHO standards for drinking water (1 mg/l). Some by-products resulting from the reaction of chlorine with organic matter (organochlorides) can however have an impact on the long term. For this reason, it is advisable not to chlorinate water that is heavily charged with organic matter.
Which impacts can organochlorides have on the organism?
Under massive and long term doses, some organochlorides have shown to be carcinogenic for rats. Nevertheless, the benefits of chlorination on short and middle term bases widely make up for this unwanted effect. For example, in 1991, after the publication of new results on the harmful effects of organichlorides, the authorities of Lima (Peru) decided to stop all chlorination in the water supply network. This resulted in a terrible cholera epidemic affecting 1 million people and killing 10'000. Water chlorination was urgently reintroduced, but several years were needed to eradicate the epidemic.
Is is it dangerous to add too much chlorine concentrate in drinking water?
Occasional chlorine over-dosage in drinking water involves absolutely no risk for health. For that matter, drinking water supplies in large cities of developing countries often have chlorine concentrations above WHO standards (up to 2 mg/l). Besides, the consumer immediately recognises the strong smell and bad taste of chlorine in drinking water when it is over-dosed. Regular quality control with the WataBlue reagent avoids such disagreements and thus enables drinking safe and good-tasting water.